HX00026786 
 
Digitized by tine Internet Arciiive 
 
 in 2010 witii funding from 
 
 Open Knowledge Commons 
 
 http://www.archive.org/details/physiologyofcarbOOpavy 
 
THE 
 
 PnTSIOLOGY OF THE 
 CARBOHYDRATES; 
 
 THEIR ArPLlCATlON AS FOOD AND RELATION TO DIABETES. 
 
 F. W. PAVY, M.D, LL.D., F.K.S., 
 
 FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS ; 
 
 CONSL'LTIXG PUVSIflAN TO, AM> FORMERLY LECTURER ON PHYSIOLOGY AND ON THE 
 
 PRACTICE OF MEDICINE AT. GUY's HOSPITAL. 
 
 (all rights of translation and reproduction reserved.) 
 
 LONDON: 
 J. & A. CHURCHILL, 
 
 n, Js'EW EUKLINGTON STIiElOT. 
 

 LONDON : 
 
 HAKRISON AND SONS, PlilNTEHS IN OKDINART TO HEU MAJIiSTV, 
 
 ST. irARTIN's lANK. 
 
PREFACE. 
 
 The carbohydrate priiicijiles constitute by far the largest portion 
 of organic matter. They thus hold a position of great significance 
 in relation to living nature. Taking origin in the vegetable king- 
 dom as a result of the operation of solar influence through living 
 matter, they primarily play a part in the scheme of life of the 
 vegetable organism, and secondarily enter, eitlier directly or indi- 
 rectly, into the food supply of animals. 
 
 It is this latter subject which is specially dealt with in this 
 volume, but a comprehensive view of the bearings of the carbo- 
 liydrates throughout both living kingdoms requires to be taken, in 
 order that a riglit understanding ma}^ be obtained of their appli- 
 cation within the animal system. The prevailing notions have 
 been constructed upon a fallacious foundation. I liave entered 
 minutely into the experimental evidence by which the error ex- 
 isting is made manifest. By the glycogenic doctrine the mind has 
 been conducted in the wrong direction, and, as a natural conse- 
 quence, the search for knowledge has hitherto resulted only in 
 fruitless gropings in the dark. Through the recognition of tlie 
 glucoside constitution of proteid matter a clue was given whicli 
 lias led to the discovery of what I venture to regard as the true 
 key to the situation. With the light that has been thrown upon 
 the question, nature can be intelligibly read, and we have simply 
 to look around and take notice of the results that are lying clearly 
 open to view before us. The new departure brings the operations 
 of animal and plant life into harmony with each other. The 
 simplest of organisms — a yeast cell for example — may, indeed, be 
 made use of to illustrate the occurrences taking place in our own 
 
bodies. Moreover, the teachings of experience in connection with 
 diiibetes, which may be pronounced to be absolutely irreconcilable 
 with the prevailint; physiological views, not only agree with, but 
 in tlie strongest manner support, the doctrine that is in this 
 volume set forth. 
 
 A life's labour, attended with unceasing laboratory work, has 
 been devoted to the attainment of the knowledge that has been 
 acquired. To the authorities of Guy's Hospital I shall ever feel 
 grateful for the assistance rendered in the cause of science by the 
 provision of laboratory accommodation througliout the period of 
 my association as a member of the acting staff. Since that period 
 I have found in the research laboratories of the lioyal Colleges of 
 Physicians and Surgeons at the Examination Hall everything that 
 could be desired for facilitating my experimental work, and thus 
 promoting advance to the goal that has now been reached. 
 
 During the many years that my investigations have been 
 carried on I have been assisted by a succession of zealous and 
 able helpers, derived from past students of the Eoyal College of 
 Chemistry. Notable amongst the assistants who have rendered 
 me valuable service are Mr. Scard, Mr. Rowntree, and Mr. Siau. 
 It is a pleasing duty to tender this acknowledgment, and it re- 
 mains for me further to say that to Mr. Rowntree I am, in addition, 
 indebted for painstaking aid in the labour involved in the issue of 
 this work. 
 
 35, Grosvenor Street, 
 Grosvcyior Square. 
 May, 189-i. 
 
TABLE OF CONTENTS. 
 
 Intboductoet Coxsidebatious. Definition of term carbohydrate. Gene- 
 sis of carbohydrate matter. Chemical constitution of carboliydrates. 
 Chemical characters and relations considered under groupings into 
 amyloses, saccharoses, and glucoses. The amylose carbohydrates — 
 cellulose — starch — glycogen - -animal gum — dextrin. The saccharoses — 
 maltose — saccharose or cane sugar — lactose or milk sugar. The glucoses 
 — dextrose or grape sugar — Ifevulose — galactose 
 
 Behaviour op Sfgars with Phenyl hydrazine. Osazones 
 
 Transmutation of CaebohtdeAtes. Transmutation by increased hydra- 
 tion — effect of acids — effect of ferment action. Transmutation by de- 
 creased hydration. Diminution of hydration by artificial means. Dimi- 
 nution of hydration by living action — in yeast cell — in sugar eane — in 
 liver. Transmutation by ferment and protoplasmic actions considered 
 in relation to the operations of life. Amylolytic or diastatic ferments. 
 Proteolytic or peptonising ferments. Synthetic power of living proto- 
 plasm. Alternate play of ferment and protoplasmic actions 
 
 fli.rcosiDES. Nature and examples of glucosides. The glucoside constitu- 
 tion of protcid matter. Discovery of the cleaving off of carbohydrate 
 from proteid — mode of experimenting — effect of different strengths of 
 potash — proteids experimented with — traceable effect produced by 
 super-heated water. Preparation and properties of tlie primary non- 
 reducing cleavage product by potash from proteid matter. Strength of 
 alcohol required for precipitation. Resemblance of non-reducing pro- 
 duct to Landwehr's animal gum. Its diffusibility. Preparation and 
 properties of the cupric oxide reducing product (sugar) derivable, 
 through the primary cleavage product, from proteid matter. Effects 
 produced by 2 per cent, and by 10 per cent, sulphuric acid on the 
 primary cleavage product. Reactions of the sugar product with 
 Fehling's solution, phenyl hydrazine, lead oxide, &c. Its negative be- 
 liaviour in relation to fermentation and optical activity. Reference to 
 other optically inactive and unfcrmentablc sugars. Susceptibility of 
 tlie primary non-reducing product of being thrown down in combina- 
 tion with copper oxide. Cleavage of carbohydrate from proteid b}' di- 
 rect action of sulphuric acid — mode of procedure — character of osazone 
 subsequently given with phenyl-hydrazine. Suggested unrecognised 
 modifications of sugars. Recovery of the cleavage sugar from its 
 
 n 2 
 
TABLE OF CONTENTS. 
 
 osazone — melting point of tlie osazono. Clearage of eavboliydrate from 
 proteid by digestire ferment action. Conclusion from whole arraj of 
 evidence presented. Synthetic formation by protoplasmic agency of 
 proteids by incorporation of carbohydrate with other matter. View held 
 with regard to participation of asparagin. Proteid matter in relation to 
 the deposition of carboliydrate as starch, cellulose, &c., in the vegetable 
 organism 
 
 Description op Analyticai Steps op Procedueb. Modes of extract- 
 ing sugar from animal structures. The sodium sulphate method. 
 Alcohol method preferable. Employment of sulphuric acid to obtain 
 information regarding the nature of the sugar present. Details of the 
 alcoholic process of extraction in the case of blood. Process for 
 separating and estimating the amylose from the other forms of 
 carbohydrate by the successive emjjioyment of potash, alcohol, sul- 
 phuric acid, and the ammoniatcd cupric test. Mode of calculating 
 the results. Application of the process to solid tissues. Difliculty 
 arising from glycogen and cleavage carbohydrate being yielded by 
 the same jirocess. Necessity of securing that the sulphuric acid 
 used for conversion into glucose exists as free acid. Time required 
 for conversion of the various carbohydrates into glucose. Vae of the 
 autoclave for facilitating the conversion. Use of citric acid for inversion 
 of cane sugar. Qualitative and quantitative testing — cupric oxide reduc- 
 ing power the basis. Composition of Fehliug's solution. Modification 
 of Fehling's solution. Q,uantitative methods. Gravimetric copper pro- 
 cess. Volumetric method — the ammoniatcd cupric test — the apparatus 
 — precautions to be observed. ExpcrimenUvl testimony to the reliability 
 of the test 
 
 Ingested Caebohydeates traced to the Portal Blood. Starch — 
 necessity for a process of digestion — action of saliva— maltose the end 
 product — effect of gastric juice — absorption from stomach — action of 
 bile and pancreatic juice — modifying influence of acids and carbonated 
 alkalis on pancreatic ferment action — action of the succus enterieus or 
 intestinal juice — its glucose-forming capacity — product of starch diges- 
 tion found in portal blood — large presence of sugar witli lower cupric 
 oxide reducing power than that of glucose. Cellulose— its resistance 
 to solvents — its susceptibility of yielding to the action of certain fer- 
 ments — question of how far this occurs in the alimentary tract. Cane 
 sugar — its position as a diffusible body — its inversion by acids — 
 presence of an inverting ferment to a slight extent in the walls of the 
 stomach, and to a much larger extent in those of the intestine^con- 
 tinued activity of the ferment after precipitation by alcohol, and drying 
 contrast in the case of the ruminant animal in relation to the invert- 
 ing ferment — inverting eifect of contact with the stomach contents — 
 inverting action of dilute acids at moderate temperatures— product 
 from ingested cane sugar found in the portal blood. Lactose — its 
 position as a diffusible body — its alleged conversion into dextrose and 
 galactose by the succus enterieus — its probable partial conversion into 
 lactic acid. Glucose — its absoi'ption as such— possible occurrence of a 
 certain amount of lactic acid fermentation 
 
TABLE OF CONTEXTS. VU 
 
 PAGE 
 
 Portal Biood in eelation to Ingested CAEDOHTiJEATES. Jmouut of 
 sugar in blood of general circulation. Procedure for obtaining portal 
 blood. Cupric oxide reducing power of sugar of portal blood and that 
 of other blood. Amount and nature of sugar in portal blood — after 
 fasting — after animal food — after starchy food — after maltose — and after 
 cane sugar 101 
 
 The LivEE in eelatiok to the Suqab debited eeom: Ingested 
 Caebohtdeates. Evidence afforded through the Blood of Sugar 
 being stopped by the Liver. Comparative states of the blood of the 
 portal and heimtic veins. Precautions requisite in collecting blood for 
 analysis to avoid fallacy from post-mortem change. Amounts of sugar 
 encountered immediately after death in portal and hepatic b'.ood. Sugar 
 arresting function of liver the protection against diabetes. Evidence 
 afforded through the Liver itself of the stoppage by it of sugar derived 
 from Ingestion. Bernard's allegation of a sugar-forming function of 
 the liver. His discovery of glycogen. Ingested carbohydrate a source 
 of glycogen. Glycogen also formed from ingested animal food. Both 
 free and combined carbohydrate in animal matter. Proteid cleavage the 
 work of digestive ferments not of the liver. General relations of glyco- 
 gen as a constituent of the liver. Not easily extracted. Amount in 
 the liver. Its diminution from post-mortem transformation. Range 
 of figures met with — influence of food — variation with age — variation 
 with kind of animal , ., 109 
 
 The Litee in eelation to Constituent Sugar. Procedure necessary for 
 ascertaining the nature of the sugar. Rapid post-mortem production of 
 sugar in the liver. Prevention of post-mortem change by boiling and by 
 freezing. Amount and nature of sugar found in the liver respectively 
 before and after the occurrence of post-mortem change. Influence exerted 
 by the body-temperature existing at the time of death. State found in 
 the liver of cold-blooded animals. The amount of sugar present in the 
 liver corresponds with that met with in the other structures of the 
 body. The sugar-forming ferment under an inhibitory influence durmg 
 life. The inhibitory influence removed under certain abnormal condi- 
 tions. Analogy of the conditions attaching to the coagulation of the 
 blood. Production of sugar in a liver removed and washed free from 
 blood. The ferment possesses a glucose-forming capacity. Production 
 of sugar in liver-substance pre\iously coagulated by alcohol. Proof 
 that the change is not due to living action. Production of sugar in alco- 
 hol-coagulated liver-substance increased in presence of blood. Influence 
 of sodium carbonate and citric acid on ferment change in the liver 132 
 
 The Blood in relation to Sugar. Nature of sugar present in blood- 
 glucose. Portal blood an exception. Amount of sugar present in 
 blood — varying statements of different observers. Special precautions 
 necessary in the collection of the blood for analysis. The condition of 
 the urine an index of that of the blood. Arterial and venous blood in 
 relation to sugar — alleged difference — source of the fallacy — precau- 
 tions required in experimenting to escape from it. Results given. 
 
TAHLE OF CnXTENTS_ 
 
 PAOK 
 
 Question of the disappearance of sugar from drawn blood —Bernard's 
 statement — my own observations at variance tliercwitli. Lejiiue's 
 Theory' regarding gl vcoljsis in blood 157 
 
 The CTrine in eeiation to Sugar. Presence of sugar in healthy urine. 
 Causes tending to its concealment. Aj^plication of Briicke's process to 
 its separation. Proof of its presence afforded by fermentation and other 
 tests. Photograpliic representations of osazone crystals obtained from 
 the sugar of the urine of various animals and of the human subject. 
 Amount of sugar in healthy urine. Eeiation of the sugar of the urine to 
 that of the blood. No tolerating capacity of the blood for obviating 
 escape of sugar with the urine. Proof afforded by sugar-injection 
 experiments. Sugar in urine in proportion to that present in blood . . . 178 
 
 McsCLE IN eeiation TO SuGAR. Mammalian animals. Nature of sugar. 
 Pliotographic representations of osazone crystals from sugar of muscle. 
 Amount of sugar in different muscles and in different animals. Ques- 
 tion of the influence of food. Non-mammalian animals 194 
 
 The Spleen in relation to Sugar. Amount and nature of sugar. Photo- 
 graphic representation of its osazone crystals 200 
 
 The Kidket in relation to Sugar. Amount and nature of sugar. 
 
 Photographic rejjresentatian of its osazone crystals 201 
 
 The Pancreas in relation to Sugar. Amount and nature of sugar 202 
 
 Thb Lung in relation to Sugar. Amount and nature of sugar. Photo- 
 graphic representation of its osazone crystals 202 
 
 The Brain in relation to Sugar. Amount and nature of sugar 204 
 
 The Placenta and Fcetus in relation to Sugar. Amount and nature 
 
 of su^ar 201 
 
 Organs of Generation of Fish and Crustacea in relation to Sugar. 
 
 Amount and nature of sugar 205 
 
 The Egg in relation to Sugar. Amount and nature of sugar. Photo- 
 graphic representation of its osazone crystals. Change accompanying 
 incubation 20S 
 
 Glycogen and Proteid-Cleavage Carbohtdrate. Carbohydrate matter 
 other than sugar belonging to animal system embraced under heading. 
 Bernard's discovery of glycogen. Author's discovery of proteid-cleavage 
 carbohydrate. The terms " glycogen " and " amyloid substance." Glyco- 
 gen analyses include proteid-cleavage carbohydrate. Comprehension of 
 the two under the term amylose carbohydrate 211 
 
 Blood and Yabious Structures of the Body in relatio.v to Amylose 
 Carbohydrate (Proteid-Cleavage Carbohydrate and Glycogen). 
 Blood — difference between portal blood and blood generally. Result of 
 
TABLE OF CONTENTS. 
 
 injecting sugar into circulation. Muscle — diiferent muscles and umscle 
 in different animals. Pancreas. Spleen. Kidney. Brain. Lung. 
 Intestinal mucous membrane. Placenta and Foetus. Grenerative struc- 
 tures of oTiparous animals 
 
 Author's conclfsions. — Gljeogenic doctrine to be abandoned. Question, 
 through standing at foundation of application of carbohydrates within 
 the system and pathology of diabetes, one of great importance. Ad- 
 vantage of studying the matter through physiology and pathology 
 conjoined. Review of facts showing that tenets of glycogenic doctrine 
 rest upon a false foundation. Liver, instead of forming sugar prevents 
 its entry into the general circulation, and thus secures escape from 
 diabetes. Representation of conditions existing in health and diabetes. 
 Diabetes a failure or an impairment of the power of disposing of carbo- 
 hydrate matter before the general circulation is reached. Ditferent; 
 degrees of impairment of power associated with different forms of 
 severity of the complaint. A class of case in which defective assimilative 
 action alone exists. Another class of case in which liberation of sugar 
 fi'om the tissues in addition takes place. Rationale of dietetic manage- 
 ment in the complaint. Purposes to which carbohydrate matter is in 
 reality applied in the economy of life. Review of what takes place in 
 living natiu'e shows that through the influence of living protoplasm 
 carbohydrate matter undergoes : (1) transmutation; (2) application to 
 the production of proteid ; (3) transformation into fat. Universality 
 of action traceable without distinction in the animal and vegetable king- 
 doms. The transmutation effected by protoplasmic agency is in the 
 direction of dehydration, whilst by ferment action and chemical agents 
 it is in the direction of increased hydration. Illustrations of application 
 of carbohydrate matter tlirough transmutation by protoplasmic agency 
 in the vegetable kingdom. Production of glycogen an instance in the 
 animal kingdom. In plant and animal alike, ferment action first hydro- 
 Ijses and renders the condition suitable for the exercise of proto- 
 plasmic action. Experiments showing that glucose introduced into the 
 circulation gives sugar in the urine with a lower cupric oxide-reducing 
 power. Application of earboliydi'ate to the production of proteid. Proof 
 afforded by yeast cell. Phenomena observable in the higher vegetable 
 organism. Support aerived from the glycoside constitution of proteid 
 matter. Bearings of peptone harmonise with its utilisation in conjunc- 
 tion with carbohydrate in the production of proteid matter. The proto- 
 plasm of the cells of the villi the operative synthetic agent. The supply 
 of carbohydrate for proteid formation in part derived from preliminary 
 cleavage, by ferment action of digestion, from the proteids of food. The 
 carbohydrate matter escaping application by the protoplasm of the cells 
 of the villi reaches the portal blood and becomes applied by the supple- 
 mentary action of the protoplasm of the cells of the liver. Liebig's 
 classification of food principles with respect to the carbohydrates no 
 longer tenable. Ti-ansfonnation of carbohydrate into fat. If carbo- 
 hydrate matter, as is believed, represents the initial condition of all 
 organic products the whole of the fat of both living kingdoms must take 
 origin directly or indirectly from carbohydrate. Protoplasm a necessary 
 
TABLE OF CONTENTS. 
 
 PAGE 
 factor. Carbon may enter proteid molecule as carboliydi'atc, aiul come 
 out a8 fat. Yeast cells aflbrd an illustration of production of fat from 
 carbohydrate. Starch precedes fat in the oily seeds. Growth of oily 
 seeds illustrate the converse process of conversion of fat into carbo- 
 hydrate. Production of fat from carbohydrate in the animal system. 
 Where and how the process occurs. Lacteals injected with milky chyle, 
 and cells of villi charged with fat after carbohydrate, as well as after 
 fatty, food. Grounds for looking upon the protoplasm of the cells as 
 exerting a transformative action. The cells of the liver perform a 
 supplementary action. Photo-engravings of the cells of the villi, and 
 of the villi in section, after carbohydrate food and during fasting. So- 
 called fatty degenci-ation of the liver in reality a functional production 
 of fat from carbohydrate. Carbohydrate possibly first incorporated into 
 ])roteid and fat, subseqi.ently cleaved off. Circumstances suggestive of 
 the fat, and likewise the lactin and casein, of milk being clea\'age pro- 
 ducts from proteid. The fat of adipose tissue may similarly take origin 
 through the intervention of proteid, and myxcedema possibly arise from 
 an imperfect performance of the process. Fatty degeneration of muscle 
 and other tissues the result of conditions favouring cleavage of fat from 
 proteid. Question broadly discussed. A delicately -adjusted balance of 
 the opposing effects of ferment and protoplasmic actions at the founda- 
 tion of the play of changes belonging to life. The vascular system 
 controlled by nerve influence, and the state of the blood, considered in 
 relation to fat deposition and diabetes 221 
 
INTRODUCTORY CONSIDERATIONS. 
 
 The carbohydrates constitute a sharply-defined group of principles 
 occurring widely and largely in the realm of organic nature. 
 
 They are composed of the three elements, carbon, hydrogen, and 
 oxygen. The number of carbon atoms in the molecule is ordinarily 
 six, or a multiple of six,* and the hydrogen and oxygen are always 
 present in the proportion to form water. 
 
 The general formula for the group may be represented as 
 {CsCHoO),,},,, ; and, looked at simply from their elementary compo- 
 sition, the constituent members stand throughout in the position 
 of hydrates of carbon. In speaking of them, however, as carbo- 
 hydrates, it is not considered that there are grounds for regarding 
 them as actual compounds of carbon with water, and the expressions, 
 therefore, that will be subsequently u.sed with reference to transforma- 
 tion, attended with increased or decreased hydration, merely imply 
 an increase or deci-ease in the proportionate amount of the elements 
 of water. 
 
 With this understanding, the term carbohydrates is a convenient 
 one for associating the bodies of the group together and distinguish- 
 ing them from other non-nitrogenous principles. 
 
 In common with ocher organic compounds, the carbohydrates have 
 their source, dii-ectly or indirectly, in the vegetable kingdom. Under 
 the influence of the sun's rays, vegetable protoplasm containing 
 
 * By artificial means, sugars with 7, 8, and 9 carbon atoms have been constructed 
 from the ordinary 6-carbon-atom sugar. Examples, as my iiriend Professor Odling, 
 of Oxford, has pointed out to me, of less than 6-carbon-atom sugars, placed in pro- 
 gressive order of descent, are presented by arabinose (CjHmOs), obtainable by 
 hydrolysis from gum arable; erythrose (CjHsO^), yielded by the oxidation of 
 erythrite, a principle extracted from lichens ; glycorose (C3II5O3), furnished by the 
 oxidation of glycerine; and glycolose (CoTIjO), derived from the oxidation of 
 glycol. 
 
i INTi;OD0CTOHY. 
 
 cliloroph)']! is endowed with the power of dissociating the elements 
 of inorganic principles, and rccombining them into organic com- 
 pounds. It is the great province of the vegetable kingdom thus to 
 play a constructive part in the economy of nature. The living proto- 
 plasm of the plant, by virtue of itn capability of acting upon matter 
 brought within the sphere of its metabolic influence, serves as an 
 instrument, through the medium of which the solar energy eti'ects 
 the changes that occur; and the energy so expended becomes locked 
 up in a latent, or potential, state in the compound formed, ready to be 
 liberated as actual or kinetic energy when the compound is destroyed. 
 In the plant the destruction of organic matter with its a.ttendant 
 liberation of energy takes place normally to a comparatively insig- 
 nificant extent, but in certain special operations, as, for instance, 
 notably in flowering and germination, it somewhat more largely 
 occurs. It is pre-eminently in the system of the animal that organic 
 matter is actively destroyed, the energy set free becoming manifest 
 in the varied activities which constitute the characteristic attribute 
 of animal life. 
 
 We cannot satisfactorily trace the steps through which the carbo- 
 hydrates are synthetically formed ; but attempts have been made in 
 this direction, one of which, the formic aldehyde hypothesis, may be 
 mentioned by way of illustration. This view assumes that formic 
 aldehyde (CH3O) is first produced, according to the equation 
 
 C02-|-HjO = CHjO-hOs, 
 
 and that this body then gives rise, by polymerisation, or the union of 
 several molecules to form one larger molecule, to a cai-bohydrate of 
 the composition CeHuOe, thus — 
 
 6(CH.iO) = CeHijOe. 
 
 But whatever the nature of the steps, we can say with complete 
 confidence that as the ultimate result carbon is separated from tie 
 carbonic acid of the atmosphere, and associated with the elements of 
 water, yielding as the product a carbohydrate. 
 
 Instead of the process, however, being a purely chemical one, of 
 the simple nature depicted above, it may happen that the carbo- 
 hydrate is the outcome of a complex physiological change. It may be 
 that a mo' e or less elemeutaiy compound is first formed, which be- 
 
GENESIS OF CAKBOIIYDKATE MATTKU. 3 
 
 comes embodied in the substance of the living protoplasm, and that 
 from this the carbohydrate is subsequently thrown off as a cleavage 
 product of protoplasmic activity. To amplify this statement : instead of 
 the carbohydrate being directly, or by intermediate steps, synthesised 
 from its elements, it may happen that these become appropriated by 
 the living protoplasm and worked up into the proteid matter of which 
 protoplasm is constituted, and from which the carbohydrate by a 
 further action is afterwards split off. The modus operandi may not 
 be the same, but the splitting ofT of a carbohydydrate from a nitro- 
 genous molecule is an event that, as is well known, may be brought 
 about by the action of chemical agents and ferments in the case of 
 glucosides. 
 
 Pasteur, many years back, showed, as will be more fully con- 
 sidered at pp. 20 — 21, that a few yeast cells placed in a medium 
 containing tartrate of ammonia, sugar, and the ash of yeast live and 
 multiply. From these simple materials the proteid of protoplasm is 
 thus built up by the agency of pre-existing protoplasm. Further, 
 carbohydrate matter is met with in the yeast organi&m in the form 
 of cellulose and glycogen : that is, in a lower state of hydration than 
 the carbohydrate matter existing in the pabulum. Seeing, as it must 
 be considered, that the sugar of the pabulum contributes with the 
 ammonia to the production of proteid, it may happen by a subsequent 
 operation that the carbohydrate is split off in an altered form, thus 
 occasioning the transmutation that is observed to occur. The step 
 from the position existing in the case of the yeast cell to that of the 
 protoplasmic matter concerned in the primary formation of carbo- 
 hydrate matter is not a wide one. The only essential difference dis- 
 cernible is that the proteid matter is constructed by the latter from 
 the more elementary materials carbonic acid, water, and ammonia, 
 in place of the formed carbohydrate and tartrate of ammonia. 
 
 I have spoken of the primary formation of carbohydrate matter, 
 and the view taken about its being a cleavage product from proteid 
 matter harmonises with the view that is held with regard to the de- 
 position of starch and cellulose derived from the preformed carbo- 
 hydrate of the plant. For growth and storage of reserve material, 
 large quantities of carbohydrate matter are being deposited as cellu- 
 lose and starch. These are derived from cai'bohydrate matter con- 
 veyed in the form of soluble sugar to the seats of deposition, and in 
 
 B 2 
 
4 INTKODUCTORY. 
 
 the transmutation that occurs it is considered probable that the sugar 
 becomes incorporated with the protoplasmic matter, through the 
 agency of wliich the operation is performed, and from which the 
 carbohydrate is split off in an altered form. Alike in the primary 
 formation of starch from inorganic materials, and in its secondary 
 formation from pre-existing carbohydrate, the protoplasmic material 
 in which the starch makes its appearance is observed to become 
 diminished in quantity, or, as it were, used up. 
 
 The actual seat of primary formation of carbohydrate matter is in 
 the chlorophyll corpuscles. These are little protoplasmic bodies 
 which, under the influence of light, are endowed with the power of 
 appropriating materials derived from the inorganic kingdom to the 
 building up of organic matter. 
 
 The form in which carbohydrate matter primarily becomes mani- 
 fest is as starch. Whether, as is by some surmised, this is preceded 
 by sugar, or whether it is not, the first visible or demonstrable carbo- 
 hydrate product is starch. As the operations of life in the chloi-o- 
 phyll corpuscles proceed, starch grannies make their appearance. 
 Sachs, describing the changes perceptible in chlorophyll corpuscles 
 by the aid of the microscope,* says : — " The old observations of 
 Naegeli and myself show that in the primitively quite homogeneous 
 green substance, starch grains, at first extremely small, become visible, 
 usually distributed in twos, threes, or more in the mass of chloro- 
 phyll of the corpuscle. These enlarge and, as they meet one another 
 daring growth, become flattened and applied close to one another 
 with plane surfaces, while their free sides remain rounded and be- 
 come arranged more or less according to the form of the chlorophyll 
 corpuscle ; occasionally, however, when they arise at the circum- 
 ference, they protrude from the chlorophyll coi'puscle. I also 
 observed almost 20 years ago that, under certain circumstances, 
 when leaves turn yellow without being diseased, the starch grains 
 grow so vigorously in the chlorophyll that the latter becomes, so to 
 speak, entirely displaced by them ; and finally, in place of the chloro- 
 phyll corpuscle, there lies a starch-grain compounded of several 
 grains." 
 
 • ' Lectures on tlie Physiology of Plants,' by Julius von Sachs, translaled by 
 H. Marshall Ward, p. 315 : Clarendon Press, Oxford, 1887. 
 
LllKMISTHY OF TIIK CAKIiOIIVDliATES. 5 
 
 Chemical Constitution. 
 
 Accordiun^ to its percentage composition, carbohydrate matter is 
 constituted of carbon with the elements of water, but its behavioar 
 under different conditions and its derivation products may be taken 
 as ahov/ing that its molecular construction is of a much moi'e complex 
 nature. I have spoken of its origin as a product of the vegetable 
 kingdom. It is not exclusively, however, through the operations of 
 living matter that its formation is capable of being effected. 
 
 Amongst the achievements of modern chemistry has been the 
 artificial synthesis of several carbohydrate bodies, and the discovery 
 of the means of effecting the similar formation of others is probably 
 only a matter of time. The labours of E mil Fischer led some years 
 back to the synthetic formation of a fermentable sugar having the 
 composition of dextrose (CgHiaOs) and closely resembling it in 
 properties, but proving to be optically inactive. This body, desig- 
 nated a-acrose, became the starting point for attaining the sjnithesis 
 of further products, amongst which were several fermentable sugars 
 of the glucose group, including ordinary dextrose and la;vulose. 
 
 A further achievement has been the successive production from a 
 six-carbon-atom sugar of sugars possessing seven, eight, and nine 
 carbon atoms in the molecule. The nine-carbon-atom sugar has even 
 been found to be susceptible of undergoing fermentation in contact 
 with yeast. In connexion with these higher, carbon-atom sugars the 
 question has been raised as to what might be the effect of feeding 
 animals on them, and the suggestion has been made that possibly 
 modified forms of glycogen, lactose, fat, and proteid might result. 
 
 Chemical Characters and Relations. 
 
 Of the several carbohydrates known, only a certain number fall 
 within the range of consideration contemplated by this work. Such 
 are cellulose, starch and its congener in the animal kingdom glyco- 
 gen, the dextrins, maltose, cane sugar, lactose, and the glucoses. 
 
 The carbohydrates comprise a class of bodies in which carbon is 
 nssociated with different proportions of the elements of water, and 
 from the relation existing between the latter and the former, a con- 
 venient basis of classification is afforded. Thus regarded, they fall 
 into three groups : — 
 
6 INTltOnUCTOUY. 
 
 1. Tlie awyloses, witli tlie formula (CsHioOj),,, wbich present tlie 
 
 lovvest degree of hydration, and stand, therefore, as the initial 
 term of the series. They include cellulose, starch, glycogen, 
 and dextrin ; 
 
 2. The saccharoses, represented by the formula CuHjiOu, and in- 
 
 cluding maltose, laciose, and cane sugar; and 
 
 3. The glucoses, which present the highest degree of hydration 
 
 and possess the formula CeHijOs. They include dextrose, 
 Itevulose, and galactose. 
 
 1 will proceed to gi^e the main characters and relations, regarded 
 from a physiological point of view, of the above-named bodies 
 arranged under the three specified heads. 
 
 The Amylases. 
 
 Cellulose, (O'eHioOj),,, stands amongst the members of the carbo- 
 hydrate group tihat have the least proportion of the elements of water 
 entering into their constitution. It belongs mainly, but not quite 
 exclusively, to the vegetable kingdom, and, constituting as it does the 
 basis material of vegetable cell walls and of woody fibre, it probably 
 ranks as the most abundant organic principle in nature. It takes 
 origin from the soluble carbohydrates or sugars by a process of de- 
 hydration effected by the agency of the metabolic power existing in 
 living protoplasm. With the chemical transformation occurring in 
 the production of cellulose through the instrumentality of metabolic 
 action, the exercise of something akin to, if not actually consisting of, 
 plastic or formative power is bi-ought into play in such a manner as 
 to give to the newly foimed material a definite structural character. 
 Thus circumstanced, cellulose may be spoken of as taking a place 
 nearer to the position of organised matter than is held by any other 
 member of the caibohydrate group. 
 
 Insolubility in the ordinary solvents is one of the chief character- 
 istics of cellulose, but the various forms of cellulose differ in this 
 respect, some being less resistant to solvent action than others. 
 Acids, unless in a concentrated form, do not dissolve it, nor is it c^is- 
 solved by potash. A ready solvent, however, happens to be afford- 
 by an ammoniacal solution of cupric oxide, and from this nienstruu. 
 it is precipitable in a flocculent form by acids. 
 
THE AMYI.OSE CARBOIlYIiKATES. 7 
 
 Cellulose gives no colour reaction with iodine alone, but with iodine 
 in the presence of sulphuric acid, or, better, zinc chloi-ide, a blue or 
 violet colour is produced. 
 
 The efiPoct of sulphuric acid upon cellulose may bo studied by 
 experimenting with cotton wadding. Immersed in the concentrated 
 acid, cotton wadding becomes dissolved, and if the solution be at once 
 largely diluted with water the cellulose is precipitated apparently in 
 an unaltered or but slightly altered foi'ni. IF, on the other baud, the 
 cellulose is allowed to remain for some time in contact with the acid, 
 dilution with water no longer leads to the production of a precipitate. 
 The cellulose has apparently become transformed into a dextrin-like 
 material, and the solution is found to possess a slight cupric oxide 
 reducing power. Thus transformed, it may be carried further by a 
 strength of acid that has scarcely any effect on untransformed cellu- 
 lose. This is shown by the greatly increased cupric oxide reducing 
 power that may be produced by boiling after diluting the acid solution 
 to a 2 per cent, strength, under the action of which cellulose is only 
 to a very slight extent influenced. 
 
 The resistance offered by cellulose to conversion into a cupric oxide 
 reducing carbohydrate by boiling with 2 per cent, sulphuric acid 
 distinguishes it from starch and glycogen, both of which bodies, on 
 boiling for an hour and a half with the strength of acid named, are 
 completely transformed into glucose. For effecting the conversion, 
 to any notable extent, of cellulose by boiling with dilute sulphuric 
 acid, a 10 or 15 per cent, strength must be employed. At higher 
 temperatures, applied by means of the autoclave, cellulose is attacked 
 by 2 per cent, acid in a manner that it is not on boiling with the 
 inverted condenser, a fact that it is necessary to bear in mind, as will 
 be subsequently explained (p. 63), in the quantitative determination 
 of starch and glycogen where accidental contamination with cellulose 
 from a filter may have occurred. 
 
 The component molecules of the composite cellulose molecule seem, 
 to judge from its stability or power of resisting the influence of 
 different agents, to be held together by a tighter bond of union than 
 in the case of other carbohydrates. 
 
 Doubtless there is much yet to be learnt about the modifications of 
 cellulose. Even chemically there are differences, some forms being 
 susceptible of undergoing conversion into sugar by an acid of insufii- 
 
8 IN'TP.nlirCTDIir. 
 
 cient strength to exert any decided amount of influence upon cotton 
 cellulose, to which the remarks in the preceding paragraph about the 
 efl^ect of acid apply, whilst, physiologically, some of them seem, 
 instead of existing iu an independent state, to be more or less bound 
 up with living matter, if not, indeed, in some phase of their history, 
 actually incorporated with it. 
 
 Starch, (CbHioOs),,, looked at in relation to animal alimentation, 
 may be regarded as by far the most important of the bodies of the 
 whole carbohydrate group. 
 
 It is very widely and largely found in the vegetable world, and is 
 the first visible product of that constructive metabolism already 
 described as taking place in all green plants. It is primarily depo- 
 sited in the leaf, and secondarily, at subsequent stages in its history, 
 in other parts of the plant, and invariably in the form of a granule. 
 The starch granule varies much in size and appearance, according to 
 the particular plant in which it is formed ; but it has always a definite 
 structure, consisting of a nucleus or hilum and concentric, or rather, 
 strictly speaking, excentric, layers. This is best made out after treat- 
 ment with chromic acid or dilute alkali. The granule is not homo- 
 geneous, but consists of two isomeric substances, starch granulosa 
 and starch cellulose, with, perhaps, intermediate forms. The gran- 
 ulose is much the more soluble, and can be dissolved out by dilute 
 acids, or by boiling, &c. If treated in the cold, the cellulose skeleton 
 remains, retaining the form of the grain, though originally con- 
 stituting only from 2 to 6 per cent, of the weight of substance. The 
 grain, when intact, is unacted upon by cold water, by reason of the 
 density of its outer layer, but when it is crushed or ruptured the 
 granulose is slowly dissolved out. Under the action of boiling potash 
 the cellulose framework becomes likewise dissolved. The solubility 
 of starch in hot water is to be accounted for by the bursting of the 
 swollen granules, which usually occurs at a temperature of from 50° 
 to 70" C, liberating the granulose and forming the " starch paste." 
 
 A solution of starch is a semi-transparent, viscid liquid, which, 
 under examination, exhibits the following properties. In presence 
 of free iodire it yields a characteristic blue colour, which disappears 
 on heating, and reappears on cooling. This behaviour is absolutely 
 distinctive of starch, and affords an easy, delicate, and reliable test 
 for its detection. 
 
THE AMVLOSK. CAUDOHYDUATES. 9 
 
 Starch solution possesses in a mai-ked degree tbe property of 
 optical activity, rotating the ray of polarised light strongly to the 
 right. This rotatory power is possessed to a variable extent by most 
 of the members of the carbohydrate group, and on it is based one 
 method of determination applicable to these bodies. 
 
 As a colloid, starch does not diffuse through animal membranes. 
 It is absolutely insoluble in alcohol and ether, and is therefore pre- 
 cipitable from its aqueous solution by these agents. It is unaltered 
 by treatment with dilute potash or soda, but boihng with dilute 
 mineral acids carries it into glucose (dextrose) through intermediate 
 cupric oxide reducing products. Diastase and other amylolytic fer- 
 ments exert an analogous action on starch, except that the process of 
 transformation, in the main, stops short at the stage of maltose, instead 
 of advancing to glucose. There are, however, some ferments in both 
 the animal and the plant which have the power of effecting complete 
 hydration into glucose. Starch is also converted into dextrin by 
 simply heating to between the temperatures of 100° and 200° C. 
 
 Starch, like the other aniyloses but unlike most of the other 
 carbohydrates, is devoid of taste. It has no cupric oxide reducing 
 power. 
 
 Glycogen, (CellioOs),,, may he regarded as the representative in the 
 animal kingdom of the starch belonging to the plant. I consider 
 that nomenclature has been unhappy in the name that has been 
 applied to this body. The term was adopted on the discovery of the 
 material from which the sugar developed in the liver after death 
 takes origin. All the amyloses are, strictly speaking, glyco-gens ; 
 and, as it happens that the physiological grounds upon which the 
 name was given to the body under consideration prove to be un- 
 tenable, it is so far a misnomer. Zoamylin would be the most 
 appropriate of the hitherto suggested designations to apply to it. 
 Its distribution and relations in the animal organism will be referred 
 to in detail in a subsequent part of this work, and in connexion 
 therewith it will here be sufficient to say that, although constituting 
 a principle especially belonging to the animal kingdom, yet it is not 
 absolutely confined to it. In a large number of fungi it has been 
 found to be present, and it seems in these organisms to take the 
 place of the starch of higher members of the vegetable kingdom. 
 An interesting point is here presented, inasmuch as the fungi con- 
 
10 IXTi:ODl'CTOI!Y. 
 
 stitute a group of organisms differing from tlie members of the 
 vegetable kingdom generally and agreeing with those of the animal 
 kingdom in the manner in \shich their aliment is sujiplied. With 
 the non-existence of chlorophyll corpuscles they present an absence 
 of starch- forming capacity, and, as a corollary, instead of having the 
 power of constructing their living matter from principles of the 
 inorganic kingdom, they are dependent, like animal organisms, for 
 their aliment upon the supply of preformed organic matter. Yeast, 
 it has been discovered, contains glycogen in large quantity, and from 
 this source it may be readily procured and ascertained to exhibit all 
 its characteristic reactions. 
 
 Glycogen is soluble in water, but much more so in hot water than 
 cold. It yields with water an opalescent or white milky liquid 
 which perhaps is not, strictly speaking, a true solution. On concen- 
 tration it assumes a transparent state, and becomes milky again on 
 ddution. 
 
 lu its various properties and modes of behaviour, glycogen is 
 almost identical with starch, the only noteworthy difference being in 
 the colour produced by treatment with iodine, which in the case of 
 glycogen is a port-wine red, instead of blue as given by starch. The 
 effects produced on the colour by heating and subsequently cooling 
 the solution are the same in each case. 
 
 By means of microchemical examination with the employment of 
 iodine, the existence of glycogen in a granular state or in the form of 
 amorphous masses within the liver cells can be demonstrated. 
 
 Animal gum (Landwehr), which is to a certain extent allied to 
 glycogen, will receive notice under the consideration of glucosides. 
 
 Dextrin, (CeHioOs),,, is produced by the action of mineral acids and 
 by diastatic or amylolytic ferments upon the amyloses which have 
 been already described. The transformations effected by the diastatic 
 ferment of malt on starch have been the subject of much careful in- 
 vestigation and of a considerable amount of controversy, and even now 
 it cannot perhaps be definitely said that a full knowledge of the steps 
 of the process has been attained. 
 
 The researches of modern investigators point to the occurrence of 
 changes of a highly complex character, and the view at the present 
 time entertained is that from the composite starch molecule molecuhs 
 become successively split off, and with the splitting off undergo 
 
THE AMVLOSE CAUBOIIYDUATES. 11 
 
 liydration into maltose, leaving at each stage a diminislied dextrin 
 molecule of unaltered percentage composition. Thus each successive 
 stage in the process yields simultaneously a substance of higher 
 hydration and a dextrin residue, which does not difler in percentage 
 composition from the original starch molecule. The hydrated portion 
 split off at each step is, according to Brown and Morris, either 
 maltose (CnH^jOn) or an intermediate product [either maltodextrin 
 (Ci2H2oOiu)2CiuH,jOii or amylodestrin (Ci2H.,oOu,)6Ci2H«oOn], which 
 speedily undergoes further hydration into maltose. 
 
 The successive unhydrated residues have all been termed dextrins. 
 Whilst retaining the same percentage composition, they present a 
 steadily diminishing molecular weight : they are all, that is to say, 
 represented by the formula (CeHioOs),,, n being diminished at each 
 successive stage of splitting off. 
 
 By the continued action of the ferment the main portion of the 
 starch undergoes conversion through intermediate stages of dextrin 
 into maltose. There remains, however, a poi-tion which offers greater 
 resistance than the rest to the change, and which is with difficulty 
 made to undergo hydration. This is the dextrin which is most 
 easily isolated and obtained for examination, and to which the de- 
 scriptions given of dextrin more especially apply. According to the 
 latest researches of Brown and Morris, it constitutes a fifth of the 
 original molecule of soluble starch, the view founded upon these 
 researches being that the first effect of the diastatic ferment is to 
 lead to the constituents of the molecule becoming ranged into five 
 separated groups, one of which is so constituted as to be more stable 
 than the others, by virtue of which it remains intact after the others 
 have undergone hydrolysis. 
 
 The dextrins which are first formed in the process of hydrolysis 
 are coloured red by iodine, and are on this account distinguished as 
 erythrodextrins ; whilst those produced from them and met with later 
 yield no colour with iodine, and are called achroudextrins. 
 
 Dextrin is produced, not only by the action of ferments and acids 
 upon starch or glycogen, but also by the mere heating of these bodies 
 when the temperature approaches 200° C. 
 
 Dextrin is uncrystallisable, and when dried is a glassy colouiless 
 body susceptible of being ground down to a white powder. It is 
 easily soluble in water, forming a clear solution possessing no decided 
 
12 iNTiionucTonY. 
 
 taste. It is precipitated by strong alcohol. Like starch and glycogen, 
 it is dextrorotatory, whence its name. Authorities have been some- 
 what at variance as to whether any of the dextrins are possessed of 
 cupric oxide reducing power. They are, however, generally considered 
 to have no reducing power. 
 
 The Saccharoses. 
 
 The principles falling under this head requiring notice are maltose 
 lactose, and cane sugar. 
 
 Maltose (CiaH^jOn), arising from the hydration of starch by the 
 incorporation of water, thus, '2C6H,„Os + H20 = Ci2H220n, is a body 
 soluble in water, alcohol, and ether, and readily diffusible. It crystal- 
 lises in the form of hard, white, fine needles. Like the amyloses, it 
 is optically active and dextrorotatory, though in a lower degree ; 
 but, unlike them, it has a distinct taste, which is faintly sweet. It 
 is, moreover, unaffected by iodine, as indeed are all the carbohydrates 
 of higher hydration than the amyloses, and it has a cupric oxide reduc- 
 ing power equivalent to 61 as compared with that of glucose taken 
 at 100. 
 
 Although maltose constitutes the end product of the action of 
 diastase, and amylolytic ferments generally, on starch and its con- 
 geners, it is susceptible of being carried on into glucose (dextrose) 
 by boiling with dilute mineral acids, as also by the agency of certain 
 ferments. The following expression represents the change : — 
 
 C.^U^^On + H^O = C.H.A + CcH.^Os. 
 
 Maltose. Dextrose. Dextrose. 
 
 Saccharose or Cane Sugar. — Identical in composition with maltose, 
 though without any genetic relation to the amylose bodies, is sac- 
 charose, sucrose, or cane sugar {C\'JiaO\i)- This sugar is found in 
 parts of many plants. It is a substance very soluble in water, and is 
 also, though less easily, dissolved by alcohol. It crystallises in large 
 monoclinic prisms, and as a crystalloid is readily diffusible. It does 
 not reduce cupric oxide. 
 
 A solution of cane sugar is, like all the bodies hitherto described, 
 dextrorotatory. By prolonged boiling, however, with water, or by 
 boiling for a short time with dilute acid, or by the action of yeast and 
 of certain unorganised ferments at ordinary temperatures, it under- 
 
THE SACCHAROSES. 13 
 
 goes a change with increase of hydration, the first indication of 
 which is the reversal of its effect on polarised light. It now rotates 
 the ray to the left instead of to the right, and from this fact has 
 received the name of invert sugar. This invert sugar on examination 
 proves to be a mixture of the two glucoses dextrose and Icevulose in 
 eqaal proportions. The greater optical activity of liBvulose accounts 
 for the Isevorotatory power possessed by invert sugar. The inversion 
 of cane sugar presents another instance of transition from the sac- 
 charose to the glucose group, and evidently consists in a simultaneous 
 hydration and decomposition of the molecule, according to the 
 equation 
 
 CioHjaOii+HoO =: CeHijOe + CfiHijOe. 
 
 Cane sugar. Dextrose. Lsevulosc. 
 
 V ^ J 
 
 Invert sugar. 
 
 Lactose or milk sugar (C12H22O11) is only known to occur in tbe 
 animal kingdom. It constitutes the saccharine principle belonging 
 to milk. It has a faintly svreet taste. It is soluble in water, but 
 much less so than cane sugar. It is insoluble in alcohol and ether. 
 Milk sugar crystallises in white, rhombic prisms. Its solution is 
 dextrorotatory, and exhibits the phenomenon of birotation : that is to 
 say, the freshly made solution causes a rotation twice as great as 
 that which it will produce after standing. 
 
 Lactose possesses cupric oxide reducing power, but discordancy 
 exists in the precise figures given for it. Many authorities express 
 the power at 74, as compared with that of glucose taken at 100. 
 Figures, on the other hand, as low as 52 have been assigned to it. 
 Unlike glucose, lactose does not effect a ready reduction of the 
 copper test solution, and thus the terminal point is modified according 
 to the precise manner in which the examination may happen to be 
 conducted. I have made a large number of observations with the 
 employment of the ammoniated cupric liquid. As in the case of 
 Fehling's solution, the terminal point of reduction is less sharply 
 defined than when other sugars are employed, but the result of my 
 observations is to place the cupric oxide reducing power of lactose 
 at 60, or a little over. 
 
 It seems, judging from what I have observed, that under boiling 
 with acetic and citric acids lactose undergoes a certain amount of 
 
14 IXTKODUCTOliY. 
 
 modification without being converted into glucose. Boiling for from 
 half an hour to an hour with citric acid of from 2 to 5 per cent, 
 strength has the effect, according to the results before me, of raising 
 tlie cupric oxide reducing power to about 74, beyond which it cannot 
 be carried by further boiling. After boiling with a similar strength 
 of acetic acid, a reducing equivalent of about 64 or 65 has been 
 found to be given. 
 
 Harmonising with these differences revealed through cupric oxide 
 reducing action, difierences are noticeable in the osazones produced 
 with phenyl-hydrazine. Lactose in its unaltered form yields, I find, 
 contrary to what is generally stated, a deposit of an amorphous, or 
 non-crystalline, character, presenting the appearance of minute spores 
 or beads. Such is what is noticed when, for example, the crystallised 
 lactose of commerce is taken and treated with phenyl-hydrazine 
 hydrochloride and acetate of soda, or phenyl-hydrazine with acetic 
 acid in the amount ordinarily recommended for employment. If, 
 however, the lactose has been previously boiled wdth, say, 5 per cent, 
 acetic acid, or even if the acetic acid used in the application of the 
 test is added in considerable excess, a crystalline osazone is pro- 
 duced, presenting the appearance of irregularly curved, whip-like 
 filaments, radiating from a central nucleus. After boiling with 
 5 per cent, citric acid, and, whether acetic acid is subsequently added 
 in conjunction with the phenyl-hydrazine or not, a crystalline osazone 
 is given, in which the wavy filaments from the nuclear masses are 
 replaced by straight spines, or flat blade- or lancet-like projec- 
 tions. After boiling with sulphuric acid, the long straight needles 
 and radiate clusters of dextrosazone and galactosazone are pre- 
 sented. 
 
 In experimenting upon lactose derived direct from milk, similar 
 results are obtained, hut it is necessary to guard against being mis- 
 led by the process adopted for separating the casein and fat pre- 
 paratory to the application of the test. If the separation be made 
 by rennet, rendered neutral to test-paper, the amorphous deposit is 
 given with phenyl-hydrazine hydrochloride and acetate of soda, or 
 with phenyl-hydrazine and acetic acid, unless the latter is used in 
 excess. If, on the other hand, the separation be made by acidification 
 with acetic acid and the apjjlication of heat, the crystalline osazone 
 described above as yielded by lactose modified by acetic acid is given. 
 
THE GLUCOSES. 15 
 
 These results are instructive, by bringing info view constitutional 
 modifications that were not previously known to exist, and suggestive 
 that much of a like nature remains to be discovered with respect to 
 otlier bodies. 
 
 Boiling' with dilute sulphuric acid converts lactose into a mixture 
 of the two glucoses dextrose and galactose in equal parts, thus: — 
 
 C,,Ho.,0„ + H,0 = CeHiaOe + CsHijOs. 
 
 Lactose. Dextrose. Galactose. 
 
 The glucose thus formed gives with phenyl-hydrazine, as already 
 mentioned, the characteristic dextrosazone needles, intermixed with 
 radiate clusters of acicular crystals — galactosazono. 
 
 Milk sugar readily undergoes the lactic acid fermentation, and 
 various micro-organisms have been mentioned as productive of the 
 change. 
 
 The Glucoses. 
 
 The only members of this group which need be here referred to 
 are dextrose, liBvulose, and galactose. All have the composition 
 CeHi^Oe. 
 
 Dextrose, known as (jrupe siigdr, is to the animal phj-siologi.st the 
 most important of the glucoses. It occurs widely in the vegetable 
 kingdom, usually in company with Irevulose. The two are found in 
 most sweet fruits, and also in honey. Dextrose is the form of sugar 
 that occurs in the ufine of diabetic subjects. It is best obtained on a 
 large scale by the action of dilute sulphuric acid on starch ; and, by 
 similar means, it is also obtainable from the carbohydrates generally 
 of lower hj'dration than itself. From glucosides it is likewise 
 derivable by the action of acids, and in some cases by that of fer- 
 ments. 
 
 Dextrose dissolves in its own weight of cold water, and is soluble 
 also, though far less readily, in alcohol. It is less sweet to the taste 
 than cane-sugar, and is highly diffusible. It crystallises in micro- 
 scopic, rhombic plates, aggregated into nodular, warty masses. It has 
 the maximum extent of cupric oxide reducing power possessed by the 
 carbohydrates. Dextrose, subjected to the influence of dilute acids 
 and the unorganised ferments, undergoes no further hydration 
 change. It readily undergoes the alcoholic fermentation in contact 
 
16 INTKODUCTOUy. 
 
 with the gi'owiug cells of yeast. Dextrose, as its name implies, is 
 dextrorotatory. It exhibits the phenomenon of birotation. 
 
 Lcevulose is a constituent, along with dextrose, of most sweet fruits, 
 and also of honey. As previously stated, it is a product of the 
 inversion of cane sugar. Its optical activity is greater in amount 
 than, and opposite in kind to, that of dextrose : that is to say, it 
 rotates the ray of polarised light further to the left than dextrose 
 does to the right. Hence the la;vorotation exerted by invert sugar. 
 
 Lasvulose is more soluble than dextrose, both in water and in 
 alcohol. It is also sweeter to the taste, being in fact as sweet 
 as cane sugar. Its power of reducing cupric oxide is the same 
 as that of dextrose. In its chemical relations, laevulose closely 
 resembles dextrose, but it is more susceptible of being altered by 
 heat and acids, and less susceptible to the action of alkalis and 
 ferments. In connexion with the remark that laevulose is more 
 readily acted upon by acids than dextrose, I may mention that in the 
 analytical determination of the nature of a sugar through the cupric 
 oxide reducing power presented before and after boiling with sulph- 
 uric acid, it is found that where laevulose is dealt with a certain 
 amount of loss is apt to ensue from the action of the acid, and thus 
 give rise to lower figures being obtained after the boiling than before. 
 
 Lrevulose crystallises from its alcoholic solution in the form of fine 
 silky needles. 
 
 Both dextrose and lasvulose, on exposure to a temperature of 
 170^ C, lose water and become converted into bodies of the composi- 
 tion CeHjoOs, called respectively glucosan and Isevulosan, both of 
 which are susceptible of i-econversion by the agency of mineral acids 
 into their original state. 
 
 Galactose is obtained, together with dexti'ose, by boiling milk sugar 
 with dilute mineral acids. It is dext]'orotatory, and exhibits birota- 
 tion. It possesses cupric oxide reducing power. It is much less 
 soluble in water and is more readily crystallisable than dextrose or 
 laavulose, and differs chemically from these bodies in yielding mucic 
 acid, and not saccharic acid, when oxidised. Otherwise it very much 
 resembles them in its properties. 
 
BEHAVIOUR OF SUGARS WITH PHENYL-HYDRAZINE. 
 
 OsAZONES. 
 
 During the past decade the researches of Emil Fischer, founded 
 upon the discovery that combinations of cupric oxide reducing sugars 
 with phenyl-hydrazine exist, have thrown much light on the constitu- 
 tion of the sugai-s, and have afforded a valuable means of separating 
 and identifying them. It is conceded that the sugars constitute 
 bodies belonging to the aldehydic and ketonic groups, and, as with all 
 aldehydes and ketones, the cupric oxide reducing sugars form com- 
 pounds with phenyl-hydrazine — compounds which possess definite 
 crystalline characters. The product is formed in two stages. In the 
 first place, one molecule of the sugar becomes united with one 
 molecule of phenyl-hydrazine, giving rise to a Jiydrazone, a body, 
 generally of a soluble nature, which in presence of an excess of 
 phenyl-hydrazine leads on to the formation of a second compound. 
 The hydrazone first formed undergoes oxidation to a certain extent, 
 and combines with a second molecule of the phenyl-hydrazine, pro- 
 ducing an osazone, a body of slight solubility, and usually of a 
 crystalline nature. The osazones derived from the different sugars 
 present characteristic differences as regards crystalline form, melting 
 point, solubility, and optical properties. By appropriate treatment 
 the sugar may be recovered from the osazone, and, moreover, it has 
 been fonnd possible, through the intervention of the osazone, to 
 convert one sugar into another, as, for instance, dextrose into 
 loBvulose. 
 
 Of the various osazones, glucosazone stands out as the one that 
 reveals itself most readily and most conspicuously. It, indeed, often 
 separates out shortly after starting exposure on the water-bath, and 
 may subsequently appear in such abundance as to give to the product 
 under examination a solid consistence. With many sugars, the 
 heating on the water-bath requires to be prolonged for from one to 
 two or three hours, and even then the osazone may not separate out 
 till after cooling or, it may be, till after standing for some hours. 
 
18 
 
 TRANSMUTATION OP CARBOHYDRATES. 
 
 la the carbohydrates we have a group of bodies presenting, as we 
 have seen, varying degrees of hydration, and it is further noticeable 
 with regard to them that they can be caiTied from one degree of 
 hydration to another in both directions. By certain means, which, 
 whilst operating within the living organism, can at the same time be 
 thrown into play at our command outside the organism, transmuta- 
 tion by increased hydration can be effected. Passage in the direction 
 of diminished hydration is very largely taking place around us, but, 
 with the triviail exceptions to be subsequently mentioned, it is only, 
 so far as appears from observation, through the agency of the con- 
 ditions existing in connexion with actually living protoplasmic 
 matter that it is susceptible of being brought about. I will give 
 consideration separately to the two kinds of transmutation. 
 
 Transmutation of Carholtydrates by Increased Hydration. 
 
 The carbohydrates of lower hydration are easily moved into a state 
 of higher hydration by the action of acids and ferments, and by both 
 these agencies we have the power of effecting at will the transmuta- 
 tion. In this way, for instance, the amyloses may be made to pass 
 into the group of saccharoses, as in the conversion of starch into 
 maltose ; and the saccharoses iuto the glucoses, as in the conversion 
 of maltose into dextrose, and saccharose into invert sugar. 
 
 The effect of acids in the transformation of carbohydrate matter is 
 so well known that the subject does not need consideration here. 
 
 Ferment action must not be confused with fermentation. Under 
 the head of fermentation are included transformations such as that 
 of sugar into alcohol and carbon dioxide, effected by the growth of 
 the Torula cerevisicu or yeast plant; that of milk sugar into lactic acid, 
 by the various micro-organisms to which the action has been 
 assigned; that of alcohol into acetic acid, by the Mycoderma aceti ; 
 those of putrefaction by bacteria; and perhaps transformations to 
 
TK.VNSMUTATION WITH IN'OKEASED HYDRATION. 19 
 
 the products of wLicli the evil effects produced upon the invaded 
 organism bj pathogenic bacilli may be in part attributable. 
 
 In these transformations we have lo deal with a molecular disrup- 
 tion of organic matter lying outside the living cell organism, but 
 within its sphere of influence — a disruption induced as a collateral 
 effect of the changes of growth taking place within the organism. 
 
 Ferment action, on the other hand, is brought about by the agency 
 of unorganised, though organic, material. It consists essentially in a 
 process of hydrolysis — a splitting-up of a composite molecule into 
 segregated parts accompanied with a fixation of the elements of 
 water. As examples may be mentioned, the conversion of starch and 
 other amyloses into maltose by diastase, ptyalin, and the amylolytic 
 ferment of the pancreas ; the conversion of cane sugar into invert 
 sugar by invertin; and the conversion of albumin and such-like 
 pi'Oteids into peptone by pepsin and trypsin. 
 
 Through zymolysis, or ferment action, even bodies of a very stable 
 nature, looked at from a general point of view, are susceptible of 
 bsing broken down and dissolved. Cellulose, for example, which is 
 resistant to the solvent influence of ordinary chemical agents, may be 
 brought with facility by ferment action into a state of solution. 
 
 A striking characteristic of the ferment, or enzyme, which effects 
 the ti-ansformation is its power of inducing an indefinite, indeed 
 almost an unlimited, amount of change, without itself undergoing 
 any appreciable alteration or loss. Further, an almost infinitesimal 
 amount of the ferment is sufficient to produce a very extensive 
 etTcct. In fact, the amount may be so small that the presence of the 
 ferment is only susceptible of recognition through the ferment action 
 to which it gives rise. 
 
 In constitution the enzymes appear to be of tJie nature of proteids, 
 but it cannot be considered as absolutely established that they are 
 so. They are soluble in water, insoluble in absolute alcohol, and non- 
 diffusible. They need not exist at their source of production in a 
 fi-ee form, but may become developed from an antecedent zymogen 
 at the moment the suitable conditions happen to be supplied. 
 
 Transmutation of Carbohydrates by Decreased Hydration. 
 Transmutations in the direction of diminished hydration are not 
 under our control to bring about in the same way as those attended 
 
 c 2 
 
20 TliANSMUTATION OF CAIiROlIYnilATES. 
 
 with increased hydration, and, as a broad proposition, it may be 
 stated that it is only through the intervention of the power belong- 
 ing to living matter that they occur. 
 
 A few instances, it is true, can be adduced in which, by artificial 
 mean?, transformations from the higher to the lower forms of hydra- 
 tion can be effected. Thus dextrose (C6H12O6), when heated to 
 170° C, loses a molecule of water, and is converted into glucosan 
 (C6H..j05),a body having the percentage composition of the amyloses. 
 LiBvulose (CeHiaOs) also, similarly treated, is converted into Isevulosan 
 (CcHiaOs) ; and cane sugar (CuHjaOu), heated a little beyond its 
 melting point (160° C), becomes transformed into a mixture of 
 liBvulosan and dextrose, thus 
 
 CnH,,0„ = CeH,„05-HC.H„0,. 
 Cane sugar. LseTulosan. Dextrose. 
 
 Both glucosan and Isevulosan are reconvertible into glucose by 
 boiling with dilute mineral acids. As another instance, may be 
 mentioned the transformation into dextrin which dextrose is said to 
 undergo (Musculus) when it is dissolved in strong sulphuric acid 
 and subsequently poured into 95 per cent, alcohol. 
 
 Some years ago I thought I had obtained evidence of the carrying 
 down of carbohydrates by ferment agency outside the body, but from 
 knowledge since acquired I have discovered that a source of fallacy, 
 wliich I was not alive to, existed. Indeed, general observation is to 
 the effect that it would be contrary to the usual order of events for 
 ferment action to produce dehydration, its characteristic effect being 
 to produce change in the opposite direction. 
 
 There can be no doubt that transmutation by dehydration is very 
 largely taking place in connexion with the operations of life, and 
 examples of its occurrence ai'e readily forthcoming. 
 
 One of the most striking and conclusive, on account of the simple 
 nature of the conditions existing, is that which is afforded by what 
 takes place as a result of the growth of yeast. From the researches 
 of Pasteur it is known that a few yeast cells placed in a medium con- 
 sisting of water, tartrate of ammonia, cane sugar, and mineral matter 
 derived from the ash of yeast, grow and multiply, and in doing so 
 supply evidence, not only of the production of proteid matter from the 
 simple materials named, but also of the dehydration of carbohydrate 
 
Tl.'ANSMUTATION WITH DECEEASICD HYDRATION. 21 
 
 matter. The carboliydrate in the pabulum is in the form of saccharose, 
 and from this we obtain the products of fermentation, products issu- 
 ing from a change taking place outside the yeast organism, and also 
 cellulose and glycogen (vide p. 10, regarding the existence of glycogen 
 in yeast), representations of transformed carbohydrate matter existing 
 within the organism. As a concurrent event associated with fer- 
 mentation, in the case of saccharose, and, in fact, as a preparatory 
 step to it, the saccharose is raised in hydration to glucose by a fer- 
 ment — invertin — belonging to the yeast, before the splitting up 
 process occurs. Whether in the appropriation also of saccharose 
 within the yeast organism it is previously carried into glucose or not, 
 in either case the production of cellulose and glycogen constitutes an 
 act of dehydration, effected by the protoplasmic matter of the cell. 
 
 Instances of dehj'dration are afforded in the higher vegetable 
 organisms by the production, from the sugar of the sap, of starch, and 
 more rarely of inulin and cellulose, for storage as reserve materials, 
 and also of cellulose for deposition as a textural material in the pro- 
 cess of gi'owth. 
 
 The production of saccharose from glucose in the ripening of the 
 sugar-cane furnishes another illustration of dehydration. I am in- 
 debted for direct information upon this point to one of my foi-mer 
 assistants, Mr. Scard, who is now at the head of the chemical depart- 
 ment of the Demerara sugar estates of the Colonial Company, and 
 whose duties include the study of the conditions influencing the pro- 
 duction of sugar in the cultivation of the cane. It appears that 
 during the period of active growth of the cane the proportion of 
 glucose existing in the juice is far greater than when the cane 
 reaches maturity, .^s the cane ripens, a gradual diminution of 
 glucose and increase of cane sugar — the one standing in proportion to 
 the other — are observed to take place. During the active period of 
 " arrowing," or flowering, the proportionate amount of glucose is 
 large. On the disappearance of the " arrow," the cane sugar in- 
 creases at the expense of the glucose, and at the end of about a 
 fortnight, the glucose is at its minimum, and the cane sugar at its 
 maximum. Subsequently, with the renewed growth of the cane, 
 attended with the throwing out of new shoots, the glucose again in- 
 creases. As a further point, it is to be stated that in the upper or 
 growing portion of the cane glucose and cane sugar co-exist in nearly 
 
22 TI!ANSMl!TATION OF CAUBOIIYDKATES. 
 
 equal proportions, whilst in the lower segments, or more matared 
 part, cane sugar is present in larger amount than elsewhere, and is 
 accompanied with only traces of glucose. 
 
 An apposite illustration of the occurrence of dehydration in the 
 animal kingdom is afforded by the production of glycogen in the 
 liver from sugar derived from the carbohydrates of the food and 
 conveyed to it in the portal blood. The matter in question will forna 
 the subject of consideration in subsequent pages of this work. 
 
 Transmutation of Carbohijdrates by Ferment and Protoplasmic Actions, 
 considered in relation to the Operations of Life. 
 
 The effects produced by ferment action, on the one hand, and by 
 metabolic protoplasmic action, on the other, are of an opposite 
 nature. In the one ease, more or less highly complex molecules of 
 matter become split up into simpler ones with the occurrence of 
 hydration. In the other, constructive and dehydrating operations are 
 carried out. Matter existing in, or which has been brought into, a 
 more or less simple molecular state is influenced in such a manner 
 that combination ensues, and the more complex molecules belonging 
 to the living organism are thus built up. Both operations proceed 
 upon identically the same lines in the two kingdoms — animal and 
 vegetable, of nature. 
 
 Ferment action, as has been stated, brenks down complex molecules 
 into simpler ones, and hydrates. Non-soluble and non-diffusible 
 matter — that is, matter the molecules of which are presumably too 
 large to pass through membranous septa — by such agency broken 
 down, becomes soluble and diffusible. With the change effected, it 
 is placed in a position to be susceptible of absorption, and thereafter 
 of transportation from one part of the living organism to another, 
 whereby it is brought within the sphere of influence of protoplasmic 
 matter for appropriation or utilisation in the living economy. 
 
 It is by the amylolytic, or diastatic, ferments that carbohydrate 
 matter is acted upon. Proteid matter yields, in a similar way, to 
 the proteolytic, or peptonising, ferments. The effects wrought upon 
 the two kinds of matter by the respective ferments are of the same 
 nature, and the two kinds of ferment action occur in common in 
 animal and vegetable organisms. The transformation of carbo- 
 
FERMENT AXD PKOTOPLASIIIC ACTIONS. 23 
 
 hydrate matter, as an event pertaining to life, is easy of observation 
 alike in the plant and the animal. The transformation of proteid 
 matter is also an event pertaining to life that has long been known 
 to be easily suscejjtible of observation in associa.tion with organisms 
 of the animal kingdom. Latterly, proteolytic ferment action has been 
 recognised as occurring in the yegetable kingdom to an extent that 
 was not formerly suspected. It is not improbable that proteolytic 
 ferment action is a phenomenon of universal occurrence in the plant, 
 and instances certainly can be brought forward in which the exist- 
 ence of an active peptonising ferment is susceptible of ready de- 
 monstration. The most notable example is found in the Carica 
 papaya; and, in reference to this, the remark admits of being made 
 that from papaw juice so large an amount of active peptonising 
 ferment, called papain, can be extracted that a place has been giveii 
 to the plant amongst the materia medica. As regards the existence of 
 peptonising ferments in the vegetable kingdom, Sachs* says : "At- 
 tention was first drawn to the occurrence of peptonising ferments in 
 the vegetable kingdom by the remarkable phenomena observed in the 
 so-called insectivorous plants. My earlier studies on the germina- 
 tion of various seeds left no doubt that seedlings dissolve and make 
 active their proteinaceous reserve rnaterials by means of peptonising 
 ferments. Gorup-Besanez was, however, the first to detect peptoijis^ 
 ing ferments in seeds .... More recently, a very eijerg.etic 
 peptonising fernient in the latex of Carica papaya has attracted par- 
 ticular attention, and a similar ferment has been detected in the 
 latex of the common fig {Ficus carica). As "we come to knqw the 
 proteinaceous reserve materials of plants better, and if we follow 
 their behaviour in the animal body also, it can scarcely be doubtful 
 that, in spite of incomplete knowledge, the assumption is, never- 
 theless, -warranted that peptonising ferments are perhaps universally 
 distributed in plants ; moreover, peptones, the result of their activity, 
 have actually been detected by Schulze in the seedlings of the 
 Lupine." 
 
 I have entered into these considerations bearing on protejds on 
 account of their undergoing, under the influence of ferment action, 
 the same kind of change as carbohydrate matter ; and, further, on 
 
 * ' Lectures on the Physiology of Plants,' by Julius von Sachs, translated by 
 H. Marshall Ward: Clarendon Press, Oxford, 1887, pp. 31t— 345. 
 
2-i TIIAN.SMUTATION OF CAliBOHYDllATES. 
 
 account of the iutcrest attaching to the analogy to bo traced in 
 the phenomena occurring in the plant and animal. 
 
 Looked at in relation to what has preceded, the province of ferment 
 action is to prepare for the exercise of protoplasmic action. But 
 ferment action probably, also, plays a part in connexion with the 
 multifarious retrogi-essive changes occurring within the system, from 
 some of which carbohydrate matter may take origin as a product. 
 The subject, however, is not as yet one that can be considered ripe 
 for profitable discussion. 
 
 Whilst ferments split up and hydrate, the processes of synthesis 
 and dehydration are the result of the action of living protoplasmic 
 matter. It is a property of living matter to possess the power of 
 converting suitable principles, brought within its sphere of influence, 
 into the likeness of itself. The power is exerted in two directions: 
 in giving form, and in producing chemical change. To these two 
 manifestations of power the terms " plastic " and " metabolic " were, 
 many years ago, applied by Schwann. Tlirough the agency of the 
 " plastic " power possessed by living protoplasm, matter in a pre- 
 viously liquid or amorphous condition acquires determinate or definite 
 form, anil, similarly, through the " metabolic " power, undergoes 
 changes of a chemical nature. This metabolic power it is that is at 
 the foundation of the chemistry of living nature — a chemistry which 
 is characterised by it.s capacity of leading, amongst other results, to 
 the construction of products of more or less complex molecular con- 
 stitution, a certain number only of which have as yet proved sus- 
 ceptible of being formed by the operation of forces brought to bear, 
 in laboratory undertakings, outside the body. Although it thus 
 happens that products are formed by the agency of living matter 
 which the chemist as yet has not been able to form through the opera- 
 tion of chemical forces in the laboratory, it is not to be contended 
 that a diflerent kind of chemical force exists in living from that 
 existing in non-living matter, but merely that in its operation in con- 
 nexion with living matter, it is brought iuto play in association with 
 circumstances of a different nature. 
 
 I have spoken of the effects produced by ferment action and proto- 
 plasmic action. I will now give illustrations showing how these 
 actions take their turn in the play of changes belonging to life. The 
 illustrations will bo drdwu frum the vegetable kingdom, where the 
 
FERMENT AXD rKOTOPLASJIIC ACTIONS. 2o 
 
 operations of life can be more easily followed than in animal organ- 
 isms. They will assist in uni-avelling the more complicated opera- 
 tions of animal life that will come before us for consideration later on 
 in this work. 
 
 The primordial, or first-formed, starch, developed in the chlorophyll 
 corpuscle, is a product of protoplasmic action. By ferment action it 
 is transformed into sugar, which passes in the sap to seats where the 
 <jpcratioiis of growth and storage are going on. Here protoplasmic 
 action again comes into play, and through its agency the sugar is 
 reduced in hydration and converted into cellalose or starch, or, it may 
 be, some other allied principle. 
 
 Take again the starch which has been deposited in a grain of 
 wheat or other seed, by protoplasmic action, as storage material for 
 service in connexion with the evolution of the embryonic organism. 
 Whilst the formation of the seed is taking place, life exists in its 
 growing structure, and it is through the property of, or the power 
 possessed by, the living matter that the sugar reaching it from the 
 juice of the plant is transmuted into, and deposited as, starch. 
 When the developmental process concerned in the production of the 
 seed is completed, life, except in the small part constituting the 
 embryo, ceases to exist, and transmutation in the direction of that 
 effected by protoplasmic action can no longer occur. The storage 
 matter possesses vrithin itself no power of resuming or re-acquiring 
 the living state v^hich existed in connexion with it at the time of its 
 deposition. But in close proximity to it there lies a minute collec- 
 tion of matter imbued with the power of starting into living activity 
 ■when the requisite conditions are supplied. This, the embryo, is the 
 part from which the act of germination proceeds, and from it there is 
 developed the ferment which leads to the conversion of the stored 
 starch into sugar. Sachs* says : " The ferments appear to be always 
 produced by the growing parts of the seedlings and buds themselves, 
 and to penetrate from these into the reservoirs of reserve materials, 
 there to dissolve or make active the constructive materials. This is 
 pai-ticularly evident in the case of seeds containing endosperm. If 
 the young seedling (embryo) is removed from the seed of the Indian 
 corn (maize), barley, or other plant, and the endosperm alone laid in 
 moist warm eaith, its starch is not dissolved and transfoi'med into 
 * Loc. cit., pp. 343—341. 
 
26 TKAXSMUTATION OF CARBOHYDKATES. 
 
 sugar." Alongside these words of the scientist of the present day, I 
 cannot refrain from placing the words of the poet, written nearly a 
 couple of centuries ago, which not only show the knowledge that at 
 such time had been acquired by observant attention, but, in an 
 eloquent manner, give expression to it. In the subjoined passage* 
 the words to which attention is directed are inserted in italics. 
 
 " Tell me why the Ant 
 Midst Summer's plenty thinks of Winter's want : 
 By constant journeys careful to prepare 
 Her stores j and bringing home the corny ear^ 
 Jig ivhat instruction does she bite the grain, 
 Lest hid in Earth, and taking root again. 
 It might elude the foresight of her care I " 
 
 The sugar which has been produced by ferment action from the 
 stored starch, being conveyed to, and falling within the sphere of 
 influence of, the living protoplasm of the embryo, becomes appropri- 
 ated and metamorphosed into the cellulose developed and deposited 
 as a constituent of the growing organism. 
 
 As a further illustration, I may cite what occurs in the case of the 
 tuber, and take as an example the potato. Starch, in the first 
 instance, is formed and deposited by protoplasmic action from sugar 
 derived from the juice of the plant. With the completion of deposi- 
 tion, the protoplasmic activity which has been previously in operation 
 ceases to manifest itself. In certain parts of the tuber, however, 
 there are little buds — "eyes," as they are called — which, as with the 
 embi-yo of the seed, under exposure to conditions favourable to 
 growth, burst forth into active life and produce a ferment that acts 
 upon the surrounding starch, reconverting it into sugar. The sugar 
 thus formed is next, by the protoplasmic action of the living matter 
 of the bud, reduced in hydration and transmuted into the cellulose 
 entering into the structure of the growing shoot. 
 
 * ' Poems on Several Occasions, by Matthew Prior, Esq.' : London, printed for 
 T. Johnson, 1720. 
 
27 
 
 GLUCOSIDES. 
 
 The glucosides Lave long been known to cliemists as a class of 
 bodies which, by the agency of ferments and by the action of acids 
 and alkalis, and even, to a slight extent, of water at elevated tempera- 
 tures, undergo a cleavage or disruption, with sugar as one of the 
 products. Formulse are given in text-books of chemistry represent- 
 ing the molecular change that occurs, and they show that the 
 phenomenon is usually attended with the incorporation of one or 
 more molecules of water. 
 
 The group comprises bodies of very variable composition. In some 
 (salicin may be mentioned as an example) only the three elements carbon, 
 hydrogen, and oxygen are pi'esent. In others — as an instance, amyg- 
 dalin — nitrogen in addition exists. In myronic acid (CioHigNSuOio), 
 a ghicoside obtained from the seed of black mustard, there is the 
 further incorporation of sulphur. Another step in the direction of 
 increasing complexity carries us to a body standing in close proximity 
 to the proteids, viz., mucin, which, as a constituent of connective 
 tissue as well as of mucus, exists extensively diffused throughout the 
 animal system. The researches of Landwehr have shown that, under 
 certain treatment, mucin yields a non-reducing carbohydrate, which 
 he has described under the name of " animal gum," possessing the 
 formula (CsHioOs)^, and that this is convertible into a cupric oxide 
 reducing, but non-fermentable, sugar, having the composition of 
 glucose (CsHijOe), which he calls " gummose." 
 
 The announcement of the glucoside constitution of mucin was at 
 first received with some mistrust, but the view has now sufficiently 
 gained credence to meet with recognition in standard works on 
 physiologicil chemistry. 
 
 My own investigations carry us yet a step further, and bring the 
 extensive group of proteids of both the animal and vegetable kingdoms 
 of nature into the class of glucosides. I will proceed to show how I 
 was led up to this discovery, and upon what grounds the statement I 
 have made is based. I will afterwards discuss the glucoside consti- 
 
28 GI.UCOSIDES. 
 
 tiition of proteid matter, looked at in relation tu the cliemistry of life. 
 Id the discussion the utilisation of carbohydrates in the construction 
 of proteid matter, and also the knowledge that has been acquired 
 regarding the nutritive chemical changes that occur in connexion 
 with vegetable life, will receive consideration. From this compre- 
 hensive survey a view will be seen to be opened out, giving to 
 glucosides a position of the deepest physiological interest and import- 
 ance, by bringing them significantly into participation, as inter- 
 mediary agents, in the play of changes appertaining to the chemistry 
 of life. 
 
 The announcement of the discovery of the glucoside constitution 
 of proteid matter was made in a communication read at the Royal 
 Society, June 8th, 1893, of which the subjoined is a transcript. 
 
 " The Gt.ocosiDE Constitution of Pkoteid Matter."* 
 " At quite an early period of my research work I adopted a process 
 for separating the glycogen of the liver, which consisted in boiling 
 with potash, pouring into alcohol, and collecting the precipitate. For 
 the purpose of estimation, the precipitated glycogen was converted 
 by means of dilute sulphuric acid into glucose, the determination of 
 which gave the information reqnii'ed. This process I afterwards 
 applied to blood and the various organs and tissues of the body, with 
 the result that, in all cases, a more or less notable amount of cupric 
 oxide reducing product was obtained. This I looked upon as taking 
 origin, as in the case of the liver, from glycogen. I gave particulars 
 of the amounts derived from various sources in a communication 
 presented to the Royal Society in 1881 (' Proceedings,' vol. 32, 
 p. 418). 
 
 " In operating upon small quantities of blood, &c., for quantitative 
 analysis, no difficulty was experienced in obtaining what I took to be 
 glycogen, from its being convertible, like the glycogen in the case of 
 the liver, into a cupric oxide reducing product, by the agency of 
 sulphuric acid ; and from my analyses I obtained very accordant 
 results. It stood otherwise, however, when large quantities were 
 operated upon with the view of collecting the product for the purpose 
 of studying its characters. In these attempts, which were undertaken 
 * lu abstract, ' Proceedings of the Rojal 8o(iet\,' toI. 54, p. 53. 
 
r.r,uro:mnE cox.stitutiox of riiOTErn MAirKn. i".i 
 
 at diilerent times upon blood, eggs, and the spleen, I invai-iably failed 
 to obtain anything like the amount that ought to have been yielded 
 according to the indications afforded by the quantitative analysis 
 conducted. It was obvious to me that there was something connected 
 with the extraction with which I was not acquainted. Perplexed at 
 the loss that was encountered, I resolved to push inquiry, and see if 
 the discrepancy could not be cleared up. From what I will proceed to 
 adduce, it will now be seen that the explanation of my former want 
 of success is sufficiently intelligible. 
 
 "A start was given by the following discovery : — It chanced that 
 my research assistant, Mr. W. S. Rowntree, conducted some examina- 
 tions, iu one set of which the analysis was uninterruptedly proceeded 
 with, whilst in the other set, duplicate specimens, after being placed in 
 contact with potash, were allowed thus to remain for several days before 
 the subsequent steps of the process were carried out. The figures 
 derived from the latter stood higher than those from the former, and 
 the difference was sufficiently marked to arouse my attention, and 
 lead me to conclude that it could only be due to the effect of the 
 varying exposure to contact with potash. 
 
 " Pursuing the suggestion emanating from what had been observed, 
 I instituted a series of experiments, in which various products were 
 exposed to the influence of potash for different lengths of time. It 
 will suffice here to cite the results obtained from those upon 
 muscle, which, from the little colour to be dealt with, yields a very 
 favourable material for experimenting with. The muscle, after 
 having been thoroughly extracted with alcohol, was di'ied and reduced 
 to a finely-divided state. Equal portions were taken, and placed in 
 contact with equal quantities of a 10 per cent, potash solution. After 
 being allowed to remain for varying periods in this state, they were 
 boiled, poured into alcohol, and afterwards proceeded with in the 
 usual way. The results obtained stood as follows : — 
 
 Cupric oxide reducing 
 
 power, expressed as 
 
 glucose per lOOO parts 
 
 of dried muscle. 
 
 Boiled at once with pota.sb 36'6 
 
 ,, after standing 3 days with potash. . 4l"8 
 6 „ „ .. 58-1 
 
 10 „ „ .. 59-2 
 
 14 „ „ .. 58-1 
 
30 GLUCOSIDES. 
 
 " After liavlng observed tte manner in wliicli tlie result was in- 
 fluenced by tbe duration of the exposure to the action of the potash, 
 
 1 tried the effect of altering the strength of the potash solution em- 
 ployed, and took for experiment separated proteids derived from 
 various sources. TLe observations shosved that a marked variation 
 occurred as a result. A 2 per cent, strength, it was found, suffices 
 for dissolving the material and subsequently yielding a good liquid 
 for titration with the ammoniated cupric solution, but the amount of 
 cupric oxide reducing product resulting from its use stands far short 
 of that met with whore a 10 per cent, solution has been employed. 
 
 " The steps of procedure were these : The material was in each case 
 taken in a water-free state. Preparatory to treatment, it was pul- 
 verised in a mortar and passed through a fiue metallic gauze sieve 
 (90 to the linear inch). Minuteness of subdivision is an important 
 condition for securing complete solution by the potash. If boiled in 
 a coarse state with potash, some particles may escape solution and 
 disintegration, and thus lead to untransformed proteid matter being 
 subsequently present when the stage of treatment with sulphuric acid 
 is reached, the effect of which is to give a violet or rose-red colour 
 (biuret reaction) in the process of titration with the ammoniated cupric 
 te5t, and thus interfere with an accurate determination being made. 
 Under proper circumstances no such interfering colour is produced. 
 About 2 grams was the quantity usually taken for analysis. This was 
 boiled in a flask, with the use of the inverted condenser, with 50 c.c. of 
 the potash solution, for half an hour, the vessel being agitated from time 
 to time, so as to rinse down the particles attaching themselves to the 
 glass above the liquid, and secure that none escaped solution. The con- 
 tents of the flask were then poured into not less than 500 c.c. of methyl- 
 ated spirit, and the beaker was placed aside until the following day 
 for the thorough settlement of the precipitate. The precipitate was now 
 collected on a glass-wool filter jslug, washed with alcohol, dissolved in 
 hot water, and, after the addition of sulphuric acid to the extent of 
 
 2 per cent., boiled for an hour and a half with the use of the 
 inverted condenser, or placed in the autoclave and submitted for half 
 an hoar to a temperature of 150° C. (about 300° F.). The acidified 
 product was then neutralised with potash, made up to a known 
 volume, thrown on to a dry filter, and finally titrated with the am- 
 moniated cupric solution. The subjoined account gives a representa- 
 tion of the results obtained. 
 
GLUCOSIDE C0X3TITUTI0N OF PKOTEID MATTEU. 31 
 
 '■ Egg Albumin. — Prepared in some of the instances by precipitation 
 with alcohol, and in the others by treating with watsr, faintly acidify- 
 ing with acetic acid, and boiling. 
 
 " With the 10 per cent, solution of potash, the results showed the 
 existence of a cupric oxide reducing power which, reckoned as 
 glucose, averaged about 30 per 1000. With the 2 per cent, potash 
 it stood at about 10 per 1000. 
 
 " Vitellin from Ynlk of Egg. — About the same average figures were 
 yielded as by egg albumin. 
 
 '^Proteids of Blood Serum. — One observation, in which the figures 
 stood at 16 per 1000 after the employment of 10 per cent, potash, and 
 at 6 per lOOO after 2 per cent. 
 
 " Proteid of Haricot Bean (classed as a globulin). — Obtained by 
 extracting with cold water, filtering the solution, and coagulating by 
 faintly acidifying with acetic acid and boiling. The absence of starch 
 was proved by iodine. 91 per lOOO constituted the figures obtained 
 after treatment with 10 per cent., 77 per 1000 after 2 per cent., and 
 47 per 1000 after 1 per cent., potash. 
 
 " Gluten from Wheat Flour. — ^ Washed till freedom from starch was 
 shown by iodine. The figures given after the employment of 10 per 
 cent, potash solution stood at 60 per 1000, and after 2 per cent, at 
 54 per 1000, in the case of one specimen ; and in that of another, at 
 53 per 1000 after 10 per cent., 30 per 1000 after 2 per cent., and 
 24 per 1000 after 1 per cent. 
 
 " As 1 have said, I formerly looked upon the cupric oxide reducing 
 product given by the process of analysis I have described as emanat- 
 ing from the presence of free glycogen. The evidence I have just ad- 
 duced negatives this view. If free glycogen or starch had been the 
 source of the reducing product, the treatment with potash would 
 have produced no effect beyond dissolving the associated nitrogenous 
 matter and placing it in a position to be separable by the agency of 
 alcohol, and no difference would have resulted from varying the 
 strength of the alkali or the length of time of contact. The con- 
 elusion, therefore, deduoible is that the cupric oxide reducing product 
 taking origin under the circumstances must be derived from some 
 other source, and that the source lies in the cleavage or disruption of 
 the proteid molecule itself. 
 
 "Besides the principles referred to above, from which, as I have 
 
:;i2 fUJ'COSIDF.S. 
 
 eliowii, a cupric oxide redacing product is to be obtained by tlie 
 cleavage action of potasb, the subjoined have also, with the results 
 specified, been subjected to treatment with potash of 10 per cent, 
 strength. 
 
 "Fibrin. — Obtained by whipping freshly drawn blood, washing the 
 stringy coagulam with water till colourless, immersing in alcohol for 
 dehydration, and afterwards drying by exposure to the air. The 
 cupric oxide reducing product yielded after treatment with 10 per 
 cent, potash amounted in one case to 2207 and in another to 
 22'72 per 1000, expressed as glucose. 
 
 " Mucin. — Obtained from the vitreous humour of sheep's and 
 bullocks' eyes by precipitation with alcohol and subsequently drying. 
 27'4 to 29'6 per 1000 constituted the range of figures yielded. 
 
 " Casein. — Obtained from milk by heating and faintly acidifying 
 with acetio acid. The coagulum after being washed was squeezed, 
 dehydrated by alcohol, and treated with ether for removal of fat. 
 The cupric oxide reducing product yielded amounted only to 2 to 4 
 per 1000. The difference here presented from the figures in every 
 case previously given is very marked, and from this and other con- 
 siderations the idea is suggested that casein may itself be a nitrogen- 
 ous cleavage product, lactose constituting the complementary 
 carbohydrate part. 
 
 " Gelatin. — It is to be noted as a point of diSei'ence from proteids that 
 no cupric oxide reducing product is obtainable from gelatin. The 
 gelatin sold under the designation of " French leaf " is the kind I 
 have submitted to examination. 
 
 " In accord with the known effect of water at elevated temperatures 
 in leading, to a greater or less extent, to the splitting up of glucosides, 
 it is found that from proteid matter a certain amount of cupric oxide 
 reducing product is similarly obtainable. After treatment of Bgg 
 albumin with water at a temperature of about 150° C. (300° F.), I 
 have obtained from the liquid a product which has given unmis- 
 takable evidence of possessing cupric oxide reducing power. 
 
 "Preparation and Properties of the Cleavage Product, susceptible of Con- 
 version into a Cupric Oxide Reducing Body (Srtgar), derived from 
 Proteid Matter. 
 
 " I have shown how, through the quantitative analyses conducted 
 
GLUCOSIDE CONSTITUTION OF PRDTEID MATTER. 33 
 
 with the ammoniated cupric solution, I was led to the discovery 
 that a cupric oxide reducing product is obtainable from proteid 
 matter. I have referred to my fruitless attempts to collect the 
 cleavage product of the action of potash in quantity, and to the 
 difficulty thereby created through the conflicting evidence presented. 
 Subsequently an instance occurred in the course of the prosecution 
 of mj researches from which I learnt that the precise strength of the 
 alcohol employed for precipitation after the boiling with potash con- 
 stituted an item of greater importance in the process than I had 
 previously realised. Looking, as I had originally done, on the pre- 
 cipitated material as glycogen, I had assumed, from the known 
 sparing solubility of this body in alcohol, Ihat as long as the existing 
 strength of spirit was not under 60 per cent, full precipitation would 
 be secured. It now became evident to me, however, that such was 
 far from being the case, and that unless much stronger spirit were 
 nsed only partial precipitation occurred. 
 
 " This information regarding the loss that may arise from the em- 
 ployment of a strength of spii-it that I had previously regarded as 
 sufficient, together with what I have shown to be the different extent 
 of cleavage effect resulting from the employment of different 
 strengths of potash, supplies the key to the explanation of the former 
 want of success attending my endeavours to obtain the product in 
 quantity. In operating upon large amounts of material, the circum- 
 stances are such as, without the knowledge of the requisite precau- 
 tions to be observed, to be likely to lead to loss both from incomplete 
 cleavage by the potash and incomplete precipitation by the spirit. 
 Suffice it that I have now no difficulty in obtaining the product in 
 any amount that may be required for the purpose of examination or 
 experiment, and I will proceed to describe the steps of procedure I 
 adopt with, for e.xample, egg albumin, which has appeared to me to 
 be the most suitable form of jaroteid to take as a representative of 
 the group. 
 
 " The whites of twelve eggs, separated from the .yolks, are broken 
 up in an egg beater, or by whipping, and poured a little at a time 
 into a large capsule of boiling water, acidulated with acetic acid to 
 the point required for obtaining a satisfactory coagulation of the al- 
 bumin. The water is strained off through muslin, and the coagulum 
 washed, squeezed, and then placed in a flask with 20 grams of potash 
 
34 GLUCOSIDES. 
 
 dissolved in a small quantity of water. The mixture is placed on 
 the water-bath for two or three hours or set aside till the following 
 day, with in either case an occasional shaking, to become liquefied. 
 The measurement of the liquid i.s now taken, and potash added to 
 the extent required to bring to a 10 per cent, strength. The flask 
 having been fitted to an inverted condenser, its contents are boiled 
 for half an hour. The liquid is next treated with acetic acid till 
 rendered faintly acid, and after filtration concentrated on the water- 
 bath to a bulk of about 100 c.c. in order to diminish the quantity of 
 alcohol subsequently required. It is now in a somewhat viscid state, 
 and if simply poured into spirit would sink as a coherent mass. To 
 avoid this, a certain amount of spirit, insufficient for precipitation, is 
 added, and aferwards the whole poured into a further quantity of 
 about 2 litres to secure that the strength of alcohol is in excess of 
 what is actually required. The material then separates out in a 
 finely divided form, and on the following day will be found to have 
 settled into a gummy mass at the bottom of the vessel, from which 
 the spirit may be removed by simply pouring off. This constitutes 
 the product from which a cnpric oxide reducing body is obtainable, 
 and which T formerly regarded as consisting of glycogen in a crude 
 state. 
 
 '•' The properties of the material thus obtained are as follows : — 
 
 " In the di-ied state it forms a hard, glassy, resinoid mass. 
 
 " It is readily soluble in water, giving a clear solution. 
 
 " It yields no colci'atiou with iodine. 
 
 " It possesses no cupric oxide reducing power. 
 
 " It is precipitable by alcohol, but alcohol of considerable strength is 
 required for the purpose. In the presence of spirit of 85 to 90 per 
 cent, it is in great part, if not completely, precipitated, settling down 
 as {in adherent, tenacious, gummy mass, from which the alcohol may 
 be decanted off, and which may afterwards be worked up by stirring 
 with a glass rod into a sticky material. With absolute alcohol, used 
 freely, it is thrown down as a finely-divided white precipitate, without 
 any tendency to coalesce into a gummy mass. When precipitated in 
 the gummy form treatment with absolute alcohol exerts a dehydrat- 
 ing action upon it, causing it to harden and assume a crumbled, in 
 place of a cohesive, state. In the presence of spirit of less than 85 
 per cent, strength, precipitation becomes more and more incomplete, 
 
GLUCOSIDE CO>fSTITUTIO>r OF PROTEID ^^ATTER. 35 
 
 and the precipitate produced by the weaker kind of spirit assumes a 
 loose or non-adherent form. The incompleteness of precipitation by- 
 moderate strengths of alcohol is readily made apparent by the 
 fu.rther precipitation that occurs upon the addition of more alcohol to 
 the supernatant spirit. 
 
 " In its physical characters it presents a resemblance to Landwehr's 
 'animal gum.' Chemically it also resembles Landwehr's 'animal 
 gum ' in forming a copper compound on beings ti-eated with cupric 
 sulphate and caustic potash, from which it is susceptible of recovery 
 by the agency of hydrochloric acid and subsequent precipitation with 
 alcohol. Landwehr's process is in substance as follows : — 
 
 " The cleavage product obtained from mucin by the action of 
 dilute hydrochloric acid is dissolved in water, and to the solution 
 are added a sufficiency of copjier sulphate and excess of caustic 
 potash. The precipitate containing the copper compound is 
 separated by filtration, assiduously washed, dissolved in as small 
 a quantity as possible of strong hydrochloric acid, and the 
 solution poured into three times its volume of absolute alcohol. 
 On placing the alcoholic liquid on the water-bath at about 60° C, 
 a flocculent precipitate almost immediately begins to separate 
 out, which constitutes the liberated "animal gum," and which, on 
 being collected and subjected to appropriate treatment witli sulphuric 
 acid, gives origin to a cupric oxide reducing product. 
 
 "I have applied this process to the product under consideration 
 derived from the action of potash upon albumin, and have found 
 that it behaves throughout like Landwehr's ' animal gum,' and 
 similarly yields a cupric o.^tide reducing body. Moreover, I have 
 further found that tliis cupric oxide reducing body gives with 
 phenylhydrazine needle crystals of glucosazone, of which I have 
 obtained micro-photographs. 
 
 " The product, it may be finally remarked, possesses the property 
 of diffusibility, a character in which it differs from the amylose 
 carbohydrates — starch, glycogen, and dextrin. I have been unable 
 to find any statement about the diffusibility or otherwise of ' animal 
 gum,' but it is described as being a constant constituent of the 
 urine, which may be regarded as indicative of its being of a diffu- 
 sible nature. 
 
 D 2 
 
3(i GLUCOSIDES. 
 
 '^ T reparation and ProperlieK of the Gupric Oxide Reducing Product 
 (Sugar) derivable, through the preceding product, from Proteid 
 Matter. 
 
 " By the action of mineral acids, the first-formed product of which 
 T have been speaking undergoes conversion into a cupric oxide 
 reducing material. For effecting this conversion, I have for years 
 past been in the habit of using 2 per cent, sulphuric acid. I was 
 under the impression, as I have already said, that the product con- 
 sisted of glycogen, and from observations upon the conversion of 
 starch and glycogen into glucose, I had formed the opinion that 
 sulphuric acid of the strength named best and most securely met 
 the requirements, Boiling for an hour and a half with an inverted 
 condenser was resorted to, unless the autoclave was used, in 
 which case half an hour's exposure to a temperature of 150° C. 
 was found to produce an equivalent effect, the results given by 
 the two methods being practically identical. Where a quantitative 
 analysis has constituted the object in view, the acid employed 
 has been subsequently neutralised with potash. The sulphate 
 of potash formed does not, under the circumstances, occasion 
 any inconvenience ; but, should it be desired to collect the re- 
 ducing product, the acid must be removed by precipitation, and 
 this is best effected by the agency of barium carbonate. The fil- 
 trate from the barium sulphate and surplus barium carbonate being 
 afterwards evaporated to dryness on the water-bath, the material 
 in the state desired is yielded. 
 
 " With regard to the cupric oxide reducing product obtained, I had 
 all along felt, from certain points coiiuectcd with its manner of re- 
 ducing the ammoniated cupric solution, that it did not consist of 
 glucose, and I several times tried to get it carried higher in cupric 
 oxide reducing power by the acid. I noticed with products which 
 had been allowed to stand for some days or weeks after boiling with 
 the acid that indications were afforded suggestive of the occurrence 
 under examination of increased cupric oxide reducing action, but the 
 evidence did not come out with sufficient distinctness to permit of 
 my drawing any definite conclusion upon the point. Moreover, I had 
 the fact before me that standing with potash was attended with an 
 increased effect, and it seemed to me unintelligible that the same 
 
GLUCOSIDE CONSTITUTION OF PROTEID MATTER. 37 
 
 result should occur from standing with the acid. In reality, how- 
 ever, there is truth in what I observed, and I can now demonstrate 
 that the body I obtained with the 2 per cent, acid is susceptible of 
 being carried into one of much higher cupric oxide reducing power. 
 What appeared to be anomalous is novv cleai-ed up. Through the 
 potash, the capacity exists for an influence to be exerted upon the 
 amount of cleavage product developed ; and through the acid, the 
 subsequent transformation may be influenced in such a manner as to 
 give a product with an increased cupric oxide reducing power, and 
 thus the semblance of an increase of material. 
 
 " It was from what I observed whilst working vy-ith the phenylhydr- 
 azine test that the suggestion was supplied which led to the next step 
 of progress. Struck with the resemblance between the deposit (not 
 crystalline, it is to be remarked) given by the reducing product 
 derived from the action of the 2 per cent, acid and that given by 
 lactose (the ordinary crystallised of commerce), I was led to re- 
 new my efforts in the direction of getting the body carried higher 
 in cupric oxide reducing joower. In experimenting with cellulose, 1 
 had found that but very slight action was produced by 2 per cent. 
 acid, but that considerable effect followed the employment of acid of 
 10 per cent, strength, and it occurred to me as possible that the body 
 I was dealing with might, as regards resistance to the action of acids, 
 stand in a similar position. I was thus led to try the effect of 10 per 
 cent, acid, and, as the result, found that the reducing power of the 
 product became nearly doubled — iu other words, became raised in the 
 proportion of from between 50 and 60 to 100. Upon the strength of 
 this result, I tried the effect of 50 per cent, acid allowed to remain 
 in contact with the prodnct for from one to three days, then diluted 
 to 10 per cent., and boiled. The result stood about the same as after 
 direct boiling with 10 per cent. acid. After 15 per cent, acid, also, a 
 like result was obtained. As yet I have failed to carry the body to a 
 higher stage of cupric oxide reducing power than that produced by 
 10 per cent, acid, but I am, nevertheless, not satisfied that the stage of 
 glucose has been reached. Indeed. I am led to think that it has not. 
 " The effect of raising the cupric oxide reducing power is to give a 
 semblance of a coii-esponding increase of material. The figures, 
 therefore, representing the amount of cupric oxide reducing product 
 expressed as glucose, obtainable from the various proteids as a result 
 
38 
 
 GLUCOSIDES. 
 
 of the employment (if 2 per cent, sulphuric acid, require, as a result 
 of the employment of 10 per cent, acid, to be nearly doubled. 
 
 " The product obtained after the separation of the sulphui'ic acid by 
 barium carbonate and evaporation to di-yness possesses the following 
 characters : — 
 
 "It presents the appearance of a sugary extractive, and possesses a 
 pronounced baked-sugar odour. 
 
 " It is very soluble in water, only slightly soluble in absolute 
 alcohol, considerably soluble in spirit of about 90 per cent, strength. 
 
 " It is readily diffusible. 
 
 "On being boiled with caustic potash (Moore's test), the solution 
 darkens in coloui'. 
 
 "It dissolves hydrated oxide of copper in the pi'esence of potash in 
 excess (Trommer's test), without the production of a biuret reaction; 
 at least, specimens are often jarocurable of which this can be said. 
 
 " With Fehling's solution it gives a strong and neat reaction, the 
 reduced oxide of copper falling as a dense I'cd precipitate. 
 
 Photo-engraving of micro-pliotograph of osazoue crj-stals from the cleavage sugar 
 from egg albumin. Magnified 400 diameters. 
 
GLUCOSIDE CONSTITUTION OF PROTEID MATTER. 39 
 
 "Heated on the water-bath forfrom two to three hours witu phenyl- 
 hydrazine and acetic acid, it yields on cooling a crystalline osazone, 
 presenting the form of needles aggregated into sheaves or brushes, 
 or clustered in a radiating manner into dense round masses. Fre- 
 quently the composite character of the round masses is only to be 
 seen on close inspection of the circumference. Whilst a certain type 
 of character is presented, variations within certain limits aie notice- 
 able, and sometimes an approach to a spike constitution is observable. 
 The crystals are soluble in alcohol, from which they may be recrys- 
 tallised. 
 
 " It gives with benzoyl chloride an insoluble compound, in accord 
 witli the behaviour of carbohydrates. 
 
 "With a-naphthol and excess of strong sulphuric acid it behaves 
 like sugar in giving a deep violet colour, and leading on dilution to 
 the formation of a violet-blue precipitate soluble in alcohol, ether, 
 and caustic potash, with the production of yellow solutions, but in- 
 soluble in hydrochloric acid, a character by which, according to 
 Molisch, the precipitate produced from sugar is distinguishable from 
 that derived from peptone and various albuminous bodies. 
 
 " With thymol and excess of strong sulphuric acid, it, again, behaves 
 like sugar, giving a deep red coloration, followed on dilution by the 
 production of a carmine-red precipitate, soluble in alcohol, ether, and 
 caustic potash, with the formation of pale yellow solutions, and in 
 ammonia with the formation of a bright yellow solution. The pre- 
 cipitate, as in the case of the «-naphthol test, is found to possess the 
 character of insolubility in hydrochloric acid. 
 
 "It is susceptible of being thrown down in combination with oxide 
 of lead, and is aftex-wards recoverable from the compound. To de- 
 monstrate this, the aqueous solution is first treated with neutral 
 acetate of lead and filtered. Ammonia is then added to the filtrate, 
 and afterwards lead acetate and ammonia as long as further pre- 
 cipitation occurs. The precipitate, which contains the sugar com- 
 pound, is collected and washed with water until by test-paper it is 
 shown to be free from ammonia. The sugar is now liberated by dis- 
 solving the pi'ecipitate in acetic acid, and the lead got rid of by 
 precipitation with sulphuric acid. From the sugar thus recovered 
 the usual reaction is obtainable with Fehling's solution (provided the 
 ammonia has been fully removed) ; and also the crystalline osazone, 
 
40 
 
 GLUCOSIDES. 
 
 with plienylhydrazinc. Subjoined is a inicro-pliotographic repre- 
 sentation of the crystals I have obtained. On comparing them with 
 those previously i-epresented, it will be seen that a somewhat modified 
 form is presented as the result of the process that the sugar has 
 passed through. 
 
 Osazone crj'stals troiii the cleavage sugar from egg albumin recovered from the 
 lead compound. Magnified 400 diameters. 
 
 " From this assemblage of positive characters, it apjjears to me that 
 there can be no doubt that the cupric oxide reducing body obtainable 
 from proteid matter consists of sugar. It is to be stated, however, 
 that I have not yet obtained it in a form to prove fermentable, and 
 Dr. Sheridan Lea, who has kindly undertaken its examination with 
 the polarimeter, informs me that he has failed to notice any rotation 
 of which he could speak with certainty. If anything, there was, 
 he adds, a tendency to Isevorotation, but amounting to not more 
 than 0°-l. 
 
 " As regards both fermentability and optical activity, it is known 
 that sugars exist without the possession of these pi'operties. Land- 
 
GLUCO.SIDE COXSTITUTION OF PKOTEID MATTER. 41 
 
 wehr's 'gummose,' which stands closely related to my cupric oxide 
 reducing product, if it is not actually identical with it, constitutes 
 an example of a sugar that does not ferment. With regard to 
 optical activity, not only are sugars known which do not exhibit this 
 property,* but there is the farther point of consideration that a rota- 
 tory power which may exist may be neutralised, and thus masked 
 by a rotation in the opposite direction due to the incidental presence 
 of other bodies. 
 
 "In addition to the evidence derivable from the positive characters 
 that have been mentioned as possessed by the cupric oxide reducing 
 product, there is the corroborative evidence to be taken into account 
 supplied by the characters of agreement observable between my 
 primary non-reducing product and Land wehr's 'animal gum.' As I 
 have already shown, the product in question caii be thrown down, 
 precisely like 'animal gum,' in combination with copper oxide, and 
 is afterwards recovei-able and convertible into a cupric oxide reducing 
 body, which, as I have further said, yields with phenylhydrazinc a 
 crystalline osazone. Two kinds of crystals are perceptible in the sub- 
 joined micro-photograph (p. 4'2), one consisting distinctly of the long 
 needles of glucosazone. In its ready mode of separating out, the 
 osazone, it may also be said, was observed to agree with that derived 
 from glucose. A 10 per cent, strength of sulphuric acid was employed 
 in obtaining the cupric oxide reducing product operated upon. 
 
 " In closing this communication, I feel it due to my assistants, Mr. 
 Rownti-ee and Mr. Sian, to acknowledge the zeal with which they have 
 
 * It is known, as a practical detail, to those who are engaged in the sugar-cane 
 industry that the glucose present in the living and growing cane is not possessed of 
 optical properties, or, at least, iC it does possess optical projierties, that they must be 
 of a natiu'e to exactly neutralise each other, for if tlie freslily-cut cane is at once put 
 through the mill the glucose contained in the extract is found not to interfere with 
 the polarimetric estimation of the cane sugar. With the glucose, on the other 
 hand, recognizable after the cane has been cut or injured, the circumstances stand 
 otherwise. The juice here contains glucose of an optically active nature, consisting 
 of ordinary invert, or transformed cane, sugar. This may greatly exceed in amount 
 the inactive glucose present in the fresh cane ; and, in proportion to its amount the 
 estimation of the cane sugar is interfered with. 
 
 Upon the question of optical activity Emil Fischer remarks that experience, in 
 connexion with the bodies belonging to the sugar group, confirms the view that for 
 every opticaUy active substance there exists an isomeric form of opposite optical 
 activity, and that the two compounds combine together to form an inactive modifi- 
 cation. 
 
42 GLUCOSIDES. 
 
 helped me in tho work that has been pei-formed. I further consider 
 it due to state that the fauilitics afforded by the Research Labora- 
 
 Osazone crystals from the sugar obtained from the primary non-reducing product 
 after recovery from its copper compound. Magnified 4O0 diameters. 
 
 tories of the Colleges of Physiciaus and Surgeons have largely con- 
 tributed to enable me to carry on my investigation work to the point 
 that has been attained." 
 
 The above transcript represents the extent to which my knowledge 
 had reached when I communicated my results to the Royal Society 
 in May last. I thought it probable that by further work, through 
 the aid of the copper precipitation of my primary non-reducing 
 product, sugar might be found to be obtainable in a sufficiently pure 
 form for submission to combustion analysis. I have exerted my 
 endeavours towards the achievement of this object. The successful 
 precipitation appears to rest upon the employment of delicately 
 balanced quantities of the agents used ; but, as stated in the com- 
 
GLCCOSIDE CONSTITUTION OF ri!OTEID jMATTEK. 43 
 
 munication above set forth, I have obtained from the copper pre- 
 cipitate a product which on being subjected to the inverting 
 influence of sulphuric acid has acquired cupric oxide reducing power, 
 and has given with phenyl-hydrazine the osazone crystals represented 
 by the photo-engraving inserted. Repetitions of the process, how- 
 ever, have not been always attended with success; and there is this 
 important consideration, that, whatever may be the case with Land- 
 wehr's animal gum obtained from mucin, my product, obtained by 
 the action of jjotash upon albumin after subjection to the copper pre- 
 cipitation process, is accompanied with other material which comes out 
 in the spirit on warming in a flocculent form, precisely as is done by 
 animal gum. This establishes a difficulty which entirely frustrates 
 the attainment of the object to which I thought the copper precipi- 
 tate might prove applicable. 
 
 Cleavage of Carhohijd rale from Proleid Mailer bij the direcl aclion of 
 Sulphuric Acid. 
 
 An extension of research upon modified lines has led to another 
 in>portant step being effected. Through the advance made, the pre- 
 liminary production of the non-cupric oxide reducing material by the 
 agency of potash is no longer needed. It turns out, in fact, that the 
 cleavage of the proteid molecule, with the liberation of sugar, can be 
 brought about by the direct treatment of albumin with sulphuric 
 acid. Thus the process for demonstrating the glucoside constitution 
 of proteid matter becomes very much simplified and shortened. 
 
 I tried, some time ago, the effect of the direct action of sulphuric 
 acid upon the proteid matter of muscular tissue. I had not then 
 worked with phenyl-hydrazine, and I could make oat nothing definite 
 through the employment of the copper test, on account of the ob- 
 scuring effect of the peptone reaction, although I felt strongly im- 
 pressed that evidence was afforded of the occurrence of a reducing 
 action. I made attempts to separate the peptone, but failed to find a 
 satisfactory means of doing so. Later, whilst working at the osa- 
 zones, it occurred to me to apply this method of sugar recognition to 
 the product of the direct action of sulphuric acid on proteid matter. 
 The result obtained was a copious production of well shaped osazone 
 crystals. 
 
44 GLUCOSIDES. 
 
 For the application of the process, 10 grams of purified, dried, and 
 finely divided (passed through a 90 to the linear inch sieve) egg 
 albumin constitutes a convenient quantity to take. As sugar is 
 originally present, which would remain undestroyed by the action of 
 the acid, it is necessary that care should be exercised to secure com- 
 plete purification. This, it maj' be considered, is effected by the plan 
 adopted, consisting of precipitating by and boiling with alcohol, sub- 
 sequently extracting with boiling water, and finally with boiling 
 alcohol. 
 
 The material to be dealt with is placed in 60 c.c. of 10 per cent, 
 sulphuric acid and exposed to heat in the requisite manner. The 
 form of osazone crystal obtained, as will be presently shown, varies 
 with the extent of influence exerted by the degree and duration of 
 the heat brought to bear. The further the action of the acid is 
 pushed, the quicker the osazone separates out and the more distinctly 
 acicular, in brush-like or stellate aggregations, the character of the 
 crystals formed. The leas complete the action, the more ball-like the 
 form of crystal presented and the less speedy the deposition. It 
 appears to me, from all I have seen, that the different forms of crys- 
 tals arise from corresponding modified forms of sugar ; and, that in 
 the first manifestation of the power of crystallising the character 
 assumed is that of a nebulous or moss-like radiate body. In the case 
 of the sugars from other sources, it is found that, the lovr'er the cupric 
 oxide reducing power, the more, apparently, does the osazone crystal 
 deviate from the acicular form belonging to the osazone derived from 
 glucose. 
 
 The suggestion arising out of these considerations is that probably 
 modifications of sugar exist beyond those which are now definitely 
 recognised and described, and that the initial product cleaved off 
 from proteid matter by the action of sulphuric acid is more or less 
 widely removed from glucose, but becomes progressively carried 
 towards it by prolongation of the action. 
 
 Doubtless much remains to be learnt regarding the extent to which 
 varying molecular combinations may occur to produce different 
 varieties of sugar. Just as cane sugar may be conceived to be con- 
 stituted of a linking together of a dextrose group and a Isevulose 
 group (with concurrent dehydration) ; maltose, of a linking of two 
 dextrose groups ; milk sugar, of a dextrose group and a galactose 
 
GLUCOSIDE CONSTITUTIOX OF PROTEID MATTER. 
 
 45 
 
 group; and raffinose, of three different glucose groups— dextrose, 
 lasvulose, and galactose : so there possibly may be other Unkings of 
 sagar groups of different degrees of hydration and in varying mult- 
 iple proportions, giving rise to a large extension of the varieties of 
 sugar beyond those at the present time particularised by chemists. 
 
 A foundation for this hypothesis is presented by the view enter- 
 tained by authorities of eminence with regard to what occurs in the 
 successive steps of hydrolysis attending the transformation of starch 
 into maltose. Amylodextrin, for instance, is spoken of as a body 
 consisting of one maltose (Ci-HjaOn) group linked with six amylose 
 (CijHjoOio) groups, and maltodextrin as a body consisting of one 
 maltose group linked with two amylose gi'oups. 
 
 After the requisite exposure to heat has been completed, the sulph- 
 uric acid employed is nearly neutralised by baryta, and neutralisa- 
 tion finished off with barium carbonate. The liquid is then brought 
 to the bulk required, and, after the addition of phenyl-hydrazine and 
 acetic acid, is heated on the water-bath for at least an hour. Crystals 
 
 Osazonc crystals from cleavage sugar obtained from egg albumin by direct action 
 of Bulphuric acid, after limited extent of action. Magnified 400 diameters. 
 
46 
 
 GLUCOSIDES. 
 
 are found to make their appearance, sometimes wliilst on the water- 
 bath, but more frequently not till cooling commences, and to go on 
 separating out for some hours aftei'wards. If the hot solution is 
 poured into a cool glass the orystiils fall in quite a shower-like 
 m:innpr, 
 
 Osazor.e crystals from cleavage sugar obtained from egg albumin by direct action 
 of sulphuric acid, after more prolonged action. Magnified 400 diameters. 
 
 From the osazone obtained the sugar is susceptible of recovery by 
 following the procedure described by Fischer. The osazone crystals 
 are collected on a glass-wool filter, washed with water, and dried. 
 They are then treated with a little strong hydrochloric acid (sp. gr. 
 1'19), quickly warmed to 40° C, at which temperature the mixture is 
 kept for one minute, next cooled to 25° C, and then allowed to stand 
 
GLUCOSIDE CONSTITUTION OF PROTEID MATTER. 47 
 
 for ten mimites. The phenyl-hydi'azine hydrocliloride wliich has 
 been formed is now separated by filtration through glass wool, and is 
 washed on the filter with a little concentrated hydrochloric acid. 
 The filtrate contains a body corresponding with the glucosone 
 described by Fischer. For the separation and purification of this 
 body, the acid is first neutralised with lead carbonate, and, after filtra- 
 tion, the liquid treated with animal charcoal. Excess of baryta-water 
 is next added, the glucosone-like body being thereby thrown down in 
 combination with lead hydrate, from which it is subsequently separ- 
 ated by the employment of dilute sulphiiric acid. After the excess 
 of sulphuric acid has been removed with barium carbonate, the 
 liquid is concentrated to a syrup by evaporation at a low tempe- 
 rature. The body thus separated has the capacity, like sugar, of 
 uniting with phenyl-hydrazine, and the following is a representa- 
 tion of osazone crystals obtained from it. 
 
 Osazone crystals from the intermediate body obtained in the process of recovery of 
 sugar from the cleavage-sugar osazone. Magnified 400 diameters. 
 
 From the intermediate body sugar is obtained by reduction with 
 zinc-dust and acetic acid. The recovered sugar is found, after 
 
48 GLUCOSIDES. 
 
 removal of the zinc present, to give a clean and definite reaction 
 with the copper test, attended vrith a distinct deposition of red 
 oxide particles. It also yields an osazone vrith phenyl-hydrazine. 
 The following is a photo-engraving fi'ora a micro-photograph of 
 crystals so obtained. 
 
 ii-d t'roju cU'a\ag 
 400 diameters. 
 
 The melting point of an osazone gives information which renders 
 assistance in the identification of its sugar. I have conducted 
 several observations, with the view of determining the melting point 
 of the osazone from the cleavage sugar from proteid matter, and 
 find that it may be stated to stand at about 189 — 190° C. It thus 
 more closely approacbes the melting point of galactosazone 
 (190—193° C.) than that of glucosazone (205° C). 
 
 From what has preceded, it will be perceived that the phenyl- 
 hydrazine test has proved of immense value in the pursuit of the 
 investigation which has revealed the glucoside constitution of proteid 
 
OLT'COSTTIE rONSTTTT'TTOX OF mOTF.Tn '\IATTF.r;. 49 
 
 matter. Tt. lins not only served to cnrroborate the indications of 
 the copper- reduction test, but has proved susceptible of application 
 wliere this test, from the presence of interfering matter, has not been 
 satisfactorily available. For instance, the product from the direct 
 action of sulphuric acid upon albumin, when treated with the copper 
 test, o-ives no reaction from which, taken alone, any reliable in- 
 formation conld be drawn. From the biuret reaction produced by 
 the peptonoid matter pi-osent a masking intlnence is exerted, and 
 the ammonia g-enerated interferes with the deposition of sub-oxide. 
 With the kuowledg'e supplied through the phenyl-hydrazine I'eaction 
 it is not difficult now to recognise, notwithstanding the obscuring 
 effect of the biuret reaction, that a reduction of the copper test in 
 reality occurs. What is observed is that the blue colour imparted 
 by the test liquid is, on boiling, removed, without the formation of 
 any precipitate. That this disappearance of colour is actually due 
 to reduction is shown by the retui-n of colour which occurs from 
 re-oxidation, when the contents of the tube are well shaken in con- 
 tact with air and allowed to stand ; and, further, by the fact that, 
 under prolonged boiling, the ammonia produced may be so far dis- 
 sipated that the deposition of a certain amount of reduced oxide is 
 permitted to take place. Had it not been for the masking action 
 of peptonoid matter, to which I have beer, referring, I venture to 
 think that the liberation of sugar from proteid matter, looking at 
 the simple and easy manner in which it is brought about by the 
 agency of sulphuric acid, would long ero now have stood in the 
 ])osition of an established fact. 
 
 Cleavage of Carboln/drafe from Proteid Matter hy Digestive 
 Ferment Artinii. 
 
 Another means can be shown to exist whereby the cleavage of 
 carbohydrate from proteid matter can be effected. By alkalis it is 
 cleaved off in a form devoid of cupric oxide reducing power, and 
 likewise of the property of producing an osazone on treatment with 
 phenyl-hydrazine, but susceptible of acquiring these properties 
 through the converting influence of sulphuric acid. By sulphuric 
 acid, applied direct, the carbohydrate is liberated in the form of a 
 reducing sugar. By the agency of proteolytic ferment action the 
 
50 GLUCOSIDES. 
 
 snmo effeob is procluoefl ns by sulplmrio acid, and \vp liave here a 
 point of much physiological importance presented. Purified egg 
 alliumin yields, under pepsin digestion, a product which gives charac- 
 teristic osazone crystals with phenyl-hydrazine. In conducting the 
 experimental work upon which this statement is based, I found that 
 precautions require to be taken to secure that no fallacy is allowed 
 to creep in. In the first place, the sugar of the egg albumin should 
 be thoroughly removed by successive extractions with boiling water, 
 or — what is better — by precipitating, ia the first instance, with 
 boiling alcohol, and, afterwards, successively extracting with boiling 
 water and alcohol ; and, in the next place, it must be ascertained 
 that the pepsin employed does not contain impurity, as many samples 
 of pepsin do, to constitute a source of osazone production. 
 
 Now, the result of experimenting with egg-albumin, which has been 
 thoroughly deprived of free sugar, and pepsin, which, taken alone 
 and exposed to contact with the acid as a counterpart experiment, 
 gives a negative result, is that osazone crystals are obtained. Before 
 concluding, however, that these crystals are derived from cleavage 
 effected actually by digestion, another counterpart experiment requires 
 to be performed, consisting in the exposure of the egg albumin to 
 contact with the acid and water without the addition of the pepsin. 
 Treatment, it is found, of the product of this procedure with phenyl- 
 hydrazine yields no crystals of osazone, thus proving that the acid 
 alone is not the operative agent. Indeed, with a strength of acid of 
 only 0'2 per cent, and exposure to the moderate temperature required 
 for digestion, no effect from the acid alone could be reasonably- 
 looked for. 
 
 From the evidence presented it is thus permissible to conclude that 
 in the process of digestion the carbohydrate constituent of the proteid 
 molecule is set free, and it will be noticed that it presents itself to our 
 view under the form of sugar. Subjoined is a photo-engraving of a 
 micro-jjhotograph of osazone crystals given by the cleavage sugar 
 arising from the digestion of egg albumin. Digestion was allowed 
 to proceed for S| hours at 54° C, the albumin in the coagulated, 
 dried, and pulverised state in which it was used proving very 
 resistant to digestive solution. 
 
GUTOSIDE CO\STITUTION OF TROTErP MATTER. 51 
 
 Osazone crystals from the cleaTage sugar given by digesting 10 grams egg albumin 
 with 0'4 gram pepsin and 100 c.c. of 0'2 per cent, hydrochloric acid. Magni- 
 fied 400 diameters. 
 
 Conclusion from Array of Evidence presented. 
 
 From what has preceded it is seen that a cleavage product is in 
 different ways obtainable from proteid matter which possesses 
 characters presenting the closest points of identity with those of 
 sugar. The reaction, especially, which it gives with phenyl- 
 hydrazine, embracing not only the crystalline form and mode of 
 separating out of the osazone obtained, but also the manner in which 
 it subsequently behaves, affords the strongest presumptive evidence 
 that sugar is present. There can be no doubt about the fact that an 
 osazone is produced, and, with the knowledge that we possess 
 regarding the derivation of osazones, it is not, it may be considered, 
 permissible, under the whole circumstances of the case, to look to 
 anything else than sugar as the source of the osazone given bj' the 
 cleavage product from proteid matter. 
 
 The negative evidence, baspd upon optic.Tl inactivity and non- 
 
52 GLTTCORIHES. 
 
 fermentability, cjumnt he poiisideved to iiivalidiitp the positive 
 evidence that is adducible. 
 
 Optical activity is a property in ronnoxioii with which ranch 
 divei'sity exists, some sugars being dextro-rotatory, others laevo- 
 I'otatory, others inactive, from the neutralising effect of the pi'esetice 
 of varieties with opposite rotatory powers, and, again, others abso- 
 lutely inactive, and not to be resolved into component active sngars. 
 Further, a sugar with rotatory power in one direction is susceptible 
 of being converted into a sugar with a rotatory power in the opposite 
 direction, as is exemplified by the convertibility of dextrose into 
 ]a3vulose (Fischer). 
 
 Fermentability is a property similai'ly circumstanced with regard 
 to diversity. Sugars, it is known, exist, even amongst the glucoses, 
 which are not fermentable, and it may happen that one form of a 
 particular group having one kind of optical activity is fermentable, 
 whilst another form, with an opposite kind of optical activity, is 
 not. For instance, ordinary l^vulose, which is Ifevo-rotatory, fer- 
 ments, whilst a dextro-rotatory form of Irevnlose which has been 
 artificially obtained is not fermentable. A similar difference is 
 observable in the dextrose group, the ordinaiy or dextro-rotatory 
 form of dextrose being fermentable, whilst the Itevo-rotatory form is 
 not (Fischer). Whatever may subsequently prove to be attainable, 
 it is not contended that the sugar from proteid matter has yet been 
 brought into the form of glucose — indeed, the evidence is to the 
 effect that it has not. Tf, therefore, so resistant to passage into 
 glucose, there is nothing surprising- in its being resistant to the fer- 
 menting influence of yeast. 
 
 Whilst the recognition of the glucoside constitution of pi'oteid 
 matter was entirely founded upon the information drawn from its 
 subjection to disintegration, the information derivable from the 
 opposite consideration fits in and supplies confirmatoiy testimony. 
 It will, in what immediately follows, be shown, upon irrefutable 
 grounds, that in the construction of proteid matter by the synthetic 
 power of protoplasmic chemistry, carbohydrate matter is a partici- 
 pating agent. If carbohydrate matter thus enters into the construc- 
 tion of the proteid molecule, it only stands in harmony with what 
 might be expected, that it should be susceptible of being again 
 liberated with tlie occurrence of disintegration. 
 
GLUCOSIUE CtJNSTITL'TlOX fiF rKOTEIIi M.VTTEK. Oo 
 
 Synlliclic Foriiiatu'ii of Prvteids by lite Incurporatiuu of t'arbohijdralc 
 with other Matter. 
 
 I will pass now to the cuusideratiou of tlie luode of origin of ]>i'o- 
 teid matter, aud as we proceed it will be found that what has to be 
 stated gives support to the view concerning- its constitution that I 
 have enunciated upon the strength of results yielded by analytical 
 investigation. It will be of advantage, as a preliminary step, to sec 
 what light is thrown upon the matter by the artificial production of 
 g'lucosides. 
 
 Various gluccjsides have been artiticially produced. Berthclot 
 found that when glucose is heated for a number of hours at 
 100 — 120" C. in contact with acetic, butyric, aud other organic acids, 
 the two enter into direct combination, with an elimination of the 
 elements of water. Fi'oni the synthesised compounds thus obtained 
 the carbohydrate may be again .split off by heating with an alkali, 
 and it is interesting to note that it reappears, not as glucose (CeUiaOe), 
 but in a state of diminished hydration, viz., as glucosan (CcHl.Os). 
 In fact, an illustration is here afforded, not only of the production of 
 a g'lucoside by the incorporation of a carbohydrate with another 
 body, but also of the subsequent separation of the carbohydrate in a 
 modified form. 
 
 If we look now to the production of proteid matter by the syn- 
 thesisiug action of living protoplasm, we meet with evidence unmis- 
 takably showing that the production may arise from the combination 
 of carbohydrate with elements derived from nitrogen- and sulphur- 
 containing compounds. 
 
 The facts connected with the growth of the yeast cell may bo 
 adduced in substantiation of what has been stated. Life is hei'c 
 carried on in so simple a manner that it is not difficult to express in 
 precise terms the phenomena that occur, and the conditions as regards; 
 materials supplied for growth may be so arranged as to furnish a 
 demonstration of the application of carbohydrate to tlie construction 
 of proteid. 
 
 As Pasteur showed, many years back, yeast cells freely multiply in 
 a medium containing sugar, ammonium tartrate, and the ash of 
 yeast The growth that here takes place implies a growth of cell 
 protoplasm, and with it a corresponding formation of proteid matter, 
 
54 OLUCOSIDES. 
 
 the only source for wLiidi is tlie group of principles contained in the 
 surrounding medium. Although it may be reasonably inferred that 
 the carbon, and the hydrogen and oxygen, of the sugar contribute to 
 the formation of the proteid, the proof of such being the case is not 
 absolute, seeing that all the elements iu question are contained iu the 
 tartaric acid of the ammonium tartrate. It is possible, however, to 
 supply a medium in which the growth will similarly take place, and 
 which contains no carbou compound except the sugar. Such a 
 medium is mentioned by Sachs* as having been devised by Adolf 
 Mayer, and is stated to consist of water, sugar, ammonium nitrate (in 
 place of the ammonium tartrate of Pasteur's liquid), acid potassium 
 phosphate, tribasic calcium phosphate, and magnesium sulphate. 
 When yeast is grown in this medium, it is self-evident that the whole 
 of the carbon requii'ed to form proteid must be derived from the 
 sugar. The example thus affords incontrovertible testimony that 
 carbohydrate, in the presence of the other requisite matter, con- 
 tributes, under the influence of the chemical power with which 
 living protoplasm is endowed, to the construction of proteid. 
 
 The nitrogen supply needed for co-operating with the carbohydrate 
 in the production of proteid may, as we have seen, be derived, in the 
 case of the growth of a simple organism like the yeast cell, from even 
 an inorganic source. In the higher vegetable organisms, where 
 nutrient substances have to be transported to distant seats of utilisa- 
 tion, the nitrogen is supplied in a more elaborated form — very 
 generally-, it would appear, in the form of what is called asparagin, a 
 crystallisablc, diffusible principle, allied as an amido-compound in 
 constitution to leucin and tyrosin, and, like these principles, sus- 
 ceptible of taking origin from the splitting up of proteid matter. 
 Asparagin is found widely diffused through the vegetable kingdom. 
 It is recognised by vegetable physiologists as a factor extensively 
 concerned in the formation of pioteid by combination with carbo- 
 hydrate matter and the sulphur of a sulphur-containing body. It is 
 especially to be found in the growing parts of plants, and appears to 
 be formed from stored nitrogenous material as a j^rinciple adapted 
 for transportation from the seats of reserve to those of active meta- 
 
 * 'Lectures on the Pliysiologj' of Plants,' by Julius vou Sachs, translated by 
 II. JIarshall Ward, p. 383 : Clarendon Press, Oiford, 1887. 
 
GLUCOSIDE CONSTITUTION OF PKOTEID MATTEK. 55 
 
 bolic change, where a ro-combiuation with carbohy relate matter is 
 asserted to take place. 
 
 The view represented, implying the joint participation of asparagiu 
 and carbohydrate in proteid formation, is founded upon observations 
 which show that when the conditions are such as to permit of carbo- 
 hydrates being present in abundance no asparagin is to be found at 
 the seat of growth, whilst, if means are taken to limit their supply, 
 as, for instance, by experimenting with slips grown in the dark or 
 with the exclusion of carbonic acid, asparagin is to be readily detec- 
 ted. It can subsequently be made to disappear by exposing the 
 shoots to strong lights, and the disappearance is coincident with the 
 formation of carbohydrates on the one band, and the production of 
 proteid matter on the other. The natural conclusion to be arrived af. 
 is that the asparagin combines with the carbohydrate and becomes 
 used up in contributing to the formation of proteid matter. 
 
 Proteid Matter and the Deposition vf Carhuhydrate in the Vegetable 
 Organism. 
 
 I have spoken of tiie participation of carbohydi'ate in the construc- 
 tion of proteid matter. I will now pass to the consideration of the 
 converse aspect of the question and speak of its splitting oft' from 
 proteid matter as an occurrence connected with the operations of life. 
 It is noticeable that starch, cellulose, glycogen, &c., are deposited in 
 the interior of the living cells of growing parts without having pre- 
 existed as such. There is no doubt, it may be considered, that they 
 are derived from sugar convey^ed to the part in the juices of the plant. 
 It is possible, it must be admitted, that they may take origin by direct 
 transmutation of this sugar through an influence exerted upon it by 
 living protoplasm, but it has been suggested as more probable that 
 their production is the result of changes in the protoplasm itself. 
 Sachs, after contending that the processes of primary starch forma- 
 tion by the chlorophyll corpuscles and secondary starch deposition by 
 the protoplasmic starch-forming corpuscles from pre-existing sugar 
 are carried out in essentially the same way, writes as follows* with 
 reference to the former: — "It is, indeed, not impossible that certain 
 more immediate constituents of the green plasma itself take part in 
 
 • Loc. cit., pp. 317 — 318. 
 
56 ULUCOSIDKS. 
 
 thu process — that decompositions and substitutions, for example, 
 take place in the molecules of the green protoplasm. This possibility 
 obtains some probability from the observation that in many (not all) 
 cases the chlorophyll substance gradually decreases in quantity and 
 at length disappears entirely, while the starch-grains are growing in 
 it." . "I hold it as ])robable that in this process the proteid 
 
 substance of the assimilating chlorophyll itself co-operates and under- 
 goes a change." 
 
 The purport of what is here said is that prottnd plays a partici- 
 pating part in the piocess of deposition of carbohydrate as fabric and as 
 store material — cellulose, starch, &c. It is true, the grounds of reason- 
 ing, as yet within our reach, do not supply the tangible evidence of the 
 splitting off of carbohydrate from proteid matter by disruptive meta- 
 bolism that is supplied of its entry by the exercise of constructive 
 metabolism. Viewing all the circumstances, however, it is pardon- 
 able to surmise that the one stands as a natural coi'ollary to the other. 
 Carbohydiate is a co-operating factor in the construction of proteid. 
 It is deposited in a foi'm different from that in which it reaches the 
 seat of deposition — a form, even, which may be said to present a 
 semblance of oi'ganised structure, and it is undoubtedly through the 
 agency, and only through the agency, of proteid as living protoplasm 
 that the deposition is effected. 
 
 With all this, the discovery, arrived at quite independently by 
 analytical manipulation, of the glucoside constitution of pi'oteid 
 matter agrees, and even might naturally be expected to follow. It 
 supplies just the link that is wanted to fit in with the other links 
 and complete the chain. 
 
 Under the view set forth, pi'oteid matter, thi-ough its glucoside con- 
 stitution, becomes of functional import in a manner, and to an extent, 
 not hitherto definitely thought of. That its carbohydrate should be 
 susceptible of cleaving off under exposure to certain influences (it 
 may be considered that ferment agency constitutes one of them) is 
 only in accord with the condition that is known to exist in the case 
 of other glucosides. 
 
 The cellulose, starch, &c., deposited as above represented, are in a 
 lower state of hydration than the sugar reaching the seat of the 
 deposition. The position may or may not be analogous, but in any 
 case it is an interesting circumstance that the carbohydrate derivable 
 
GUXOSIDE L0-N8TITrTl()N nl I'KUTKIH MATTEli. ■? I 
 
 fioui artificial glucosides is, as 1 Lave id-oviously stated (p. 53), 
 .similarly of a less bydrated form tliau the sugar employed in their 
 eonstructiuii. 
 
 These eonsideratious, drawn I'roiu vegetable physiology, will lie 
 found later on to render service in studying- the relations of earho- 
 hydrate matter in the animal system. 
 
58 
 
 DESCRIPTION OF ANALYTICAL STEPS OF PROCEDURE. 
 
 A DEsCRirnoN requires now to bo given of the methods which ex- 
 perience shows to be necessary for effecting the recognition and 
 estimation of the different carbohydrates which may be present in 
 animal products. It is obvious that these products are, without pre- 
 paration, not in a fit state for examination, and before any tests can 
 be applied, it is necessary to obtain suitable liquids for the purpose. 
 This preliminary treatment must be conducted in such a manner as 
 to be unattended with a destruction of carbohydrate, or with a change 
 in the nature of the carbohydiute beyond such intentional change as 
 conversion into glucose. 
 
 Where it is simply required to detect the presence of sugar, with- 
 out reference to its nature and amount, a process of aqueous extrac- 
 tion may be resorted to for obtaining a liquid for testing. Thus, for 
 instance, by boiling the product with a suEScient quantity of sodium 
 sulphate crystals or by boiling after exact neutralisation with acetic 
 acid, the colouring and albuminous matters are completely separated, 
 and a perfectly clear and colourless liquid containing the sugar is 
 obtained. 
 
 This method is an excellent one for purposes of qualitative testing, 
 but it is inappropriate for use where it is required to ascertain the 
 nature and (unless the nature is previously known) the amount of 
 the sugar existing. For obtaining this information it is necessary to 
 determine the cupric oxide reducing power of the product in its 
 initial state, and again after subjection to the glucose-forming 
 influence of sulphuric acid. With an aqueous extraction, figures 
 due to the presence of carbohydrate matter other than sugar would 
 be given after treatment with sulphuric acid, and error would thus 
 be introduced into the result. On this account an agent like alcohol, 
 which takes up sugar but not the other carbohydrate matter, must, as 
 will be presently more particularly mentioned, be employed for the 
 purpose of extraction. If the material present is known to consist 
 of glucose or any other particular form of sugar, a simple deter- 
 
, I'KEPAKATION KOK ANALYSIS. 59 
 
 niinationof its cupric oxide I'educing power, witliout tlie employment 
 of acid, will suffice for ascertaining its amount ; and the sodium sulph- 
 ate method, as affording an easier and more speedy process, may then 
 be made use of for obtaining a liquid for quantitative examination. 
 The following is a description of the procedure in this case to be 
 adopted, where blood, taken as an example, is the product dealt with. 
 About 40 grams of sulphate of soda iu small crystals are weighed 
 out iu a beaker or capsule. About 20 c.c. of the blood intended for 
 analysis are then poured upon the crystals, and the beaker and its con- 
 tents again weighed. In this manner the weight of the blood taken is 
 ascertained. The blood and crystals are well stirred together with a 
 glass rod, and about 30 c.c. of a hot concentrated solution of sulphate 
 of soda added. The vessel is placed over a flame guarded by wire 
 gauze, and the contents heated till a thoronghly formed coagulum is 
 seen to be suspended in a clear, colourless liquid, to attain which 
 actual boiling for a short time is required. The liquid is next to be 
 separated from the coagulum. This is done by straining through a 
 piece of muslin resting in a funnel. Some of the hot concentrated 
 solution of sodium sulphate is then poured on the coagulum, well 
 stirred up with it, and the whole thrown on the piece of muslin. 
 The coagulum is squeezed, and, to secure that no sugar is left behind, 
 is returned to the beaker, and the process of washing and squeezing 
 repeated. 
 
 The somewhat turbid liquid is next thoroughly boiled, and then 
 filtered through filter paper, when a perfectly clear filtrate is 
 obtained. The washing of the beaker and filter with the hot concen- 
 trated solution of sodium sulphate completes the process of pre- 
 paration. The liquid yielded is iu an excellent condition for the 
 quantitative determination of the sugar, by either of the methods, 
 gravimetric or volumetric, presently to be described. 
 
 The process, as I have already stated, is only suitable for applica- 
 tion where the nature of the sugar present is known. Where its 
 nature is not known, a single determination, on account of the dif- 
 ferent degrees of cupric oxide reducing power possessed by the 
 various sugars, suffices only to reveal the amount of reducing power 
 belonging to the product, there being nothing to show whether this 
 is representative of a certain amount of glucose or a larger quantity 
 of some bjdy or bodies of lower cupric oxide reducing power. 
 
fiO ANALYTICAL STEPS OK I'ltOCEDlIUK. 
 
 'I'd iicquire informatiou regarding the nature of tlie material, a 
 method of extraction must be resorted to which will admit of the 
 sugar being obtained free from admixture with other carbohydi/ate 
 matter (glycogen, &(;.). By means of alcohol the desired separation 
 is effected, the sugar being taken up in solution, whilst the other 
 carbohj'di-ate matter remains in the coagulated residue. The extracted 
 carbohydrate being subsequently subjected to the converting intlueucc 
 of sulphuric acid, the determination of its cupric oxide reducing 
 power, liotli before and after this treatment, affords an insight into 
 the nature of the sugar present. If the two results coincide, the 
 existence of glucose is indicated. If the figures yielded by the first 
 determination are lower than those given by the second, it is indicative 
 of the existence of a body or mixture of bodies of lower cupric oxide 
 reducing power than glucose. 
 
 A single determination of cupric oxide reducing power is tlius of 
 no actual value, unless the particular form of sugar present is known. 
 A failure to grasp the importance of this fact is calculated to lead to 
 more or less extensive error in estimating quantities of carbohydrates. 
 Maltose, for instance, has a reducing power of only 61 as compared 
 with that of glucose taken at 100. Representative solutions, therefore, 
 containing respectively GI parts by weight of glucose and 100 paits of 
 maltose, would exert precisely the same cupric oxide reducing effect, 
 and would appear, as the result of a single determination, to contain 
 equal amounts of carbohydrate. If each, however, were then boiled 
 with dilute suljahuric acid and again examined, the results obtained 
 would be widely diffei'ent, that from the glucose-containing liquid 
 remaining as before, whilst the figures yielded by the other would 
 show a proportional advance of from 61 to 100. In the case of a low 
 reducing mixture of maltose and dextrin, such as I'esults in the early 
 sUiges of the transformation of starch and glycogen, the error arising 
 from reliance on a single determination of the cupric oxide reducing 
 action would be considerably gi-eater, and would, therefore, lead to 
 the carbohydrate being estimated at a mere fraction of the amount 
 actually present. 
 
 The details of the process of sugar extraction by means of alcoliol, 
 and the su^bsequent treatment of the residue for the collection and 
 estimation of the carbohydrate, other than sugar, obtainable in the 
 
PEEPATJATIOX FOR ANAT,Y«TS. 61 
 
 examination, for instance, nf bloorl, wliich wns tnlcen ns an example 
 before, are as follows : — 
 
 About 30 grams of defibrinated blood are poured into about 400 e.c. 
 of alcobol. Care must be taken that the spirit employed is free 
 from impregnation with anything capable of sitbsequently exerting a 
 cupric oxide reducing action. Ordinary methylated spirit may be 
 used if it has been previously redistilled. If any doubt is felt as to 
 its cliaracter, a control experiment may be performed with a portion 
 of spirit to which blood has not been added. 
 
 The sugar present in the blood jJasses into solution in the alcohol. 
 It is held, however, very tenaciously by the coagulated matter, and 
 requires to be carefully extracted from it by repeated washing and 
 pressing. The blood and spirit are well stirred together, and it ap- 
 pears to be of advantage towards obtaining as slightly coloured a 
 product as possible for subsequent testing to allow the mixture to 
 stand until the following day. After being exposed for a time to the 
 heat of a water-bath, for the purpose of promoting the agglomera- 
 tion of the precipitate, the alcohol is strained off through muslin 
 which has been previously deprived b)' thorough washing with boil- 
 ing water of its dressing of starchy matter. Washing with alcohol 
 is performed, and the coagulum in the muslin is subjected to forcible 
 squeezing in a suitable press. The residue, which by this process is 
 converted into a dry cake, is pulverised in a mortar, mixed with fi'esh 
 spirit, boiled over the water-bath, and again strained and pressed. 
 The process is repeated once more. After this third extraction, the 
 residue may be considered to be free from sugar, an aqueous extract 
 failing to exert any cupric oxide reducing action. 
 
 Two extractions with alcohol might prove sufficient, if carefully 
 made, but it is safer to use three. After the first extraction, thei'o 
 is evidence that a considerable quantity of sugar still clings to the 
 cnngulum. This is rendered apparent by the following results of 
 actual observation. Upon one occasion 50 c.c. of slieep's blood were 
 extracted with alcohol : the first extract contained 0015 gram of 
 glucose, the second 0004 gram, and the third no definite amount. 
 Again, some sugar from diabetic urine was added to sheep's blood, 
 and 50 c.c. were taken : the first alcoholic extract was found to con- 
 tnin 0']44 gram of glucose, the second 01)09 gram, and the third 
 
b2 ANALYTICAL STRPS OF PROCEDURE, 
 
 untiling dcfiuito. Tliese examples suffice to show the necessity of 
 attention being given to secure complete extraction of the sugar. 
 
 The three alcoholic extracts, incorporated together, arc now acidifierl 
 with acetic acid, then heated to near the boiling point over the water- 
 bath, and finally filtered through ordinary filter-paper. Whilst the 
 residue on the filter is reserved to be subsequently dealt with in con- 
 junction with the bulk of residue previously collected, the filtrate is 
 evaporated nearly to dryness on the water-bath, and then briskly 
 boiled with a few crystals of sulphate of soda or a few c.c. of its 
 saturated solution, for the purpose of causing the colouring and fatty 
 matters to agglomerate so as to be easily removed by filtration. The 
 liquid is filtered off, and, to avoid the inconvenience of the crystallisa- 
 tion that may take place when a filter-paper is used, it is found ad- 
 vantageous to have recourse to filtration through a plug of glass- 
 wool. The beaker and filter are then washed with the hot solution of 
 sulphate of soda. Attention, it may be stated, should be given to 
 secure that the sulphata of soda employed is free from any admixture 
 of carbonate, as this impurity may vitiate the result by exerting, 
 through its alkalinity, a destructive influence upon the sugar, besides 
 leading to the production of a more coloured liquid for testing. 
 
 The filtrate obtained presents the product of alcoholic extraction 
 in a suitable form for the quantitative determination of the sugar. It 
 is made up with water to a known volume — conveniently to 100 c.c. — 
 and then divided into two equal portions. One portion is at once 
 examined, and its cupric oxide reducing power ascertained. The 
 other is submitted, after the addition of sulphuric acid to the extent 
 of 2 per cent., to appropriate ti'eatment for the conversion of the 
 carbohydrate matter present into glucose. Another determination of 
 cupric oxide reducing power is subsequently conducted, in order that 
 a comparison may be made between the two. As a preliminary step, 
 however, the neutralisation of the sulphuric acid that has been used 
 i-eqnires to be effected. For this purpose a sti-ong solution of caustic 
 potash is employed, and, since hot potash rapidly destroys glucose, the 
 liquid product must first be thoroughly cooled, and precaution taken 
 to add the potash slowly so as to avoid any marked rise of tempera- 
 ture. The liquid is then brought up with water to a given bulk and 
 filtered through a dry filter. It frequently happens that more or less 
 colour appears as tli-e result of neutralisation, and sometimes, after 
 
PREPAKATION FOK ANALYSIS. 63 
 
 standing, n cevtain amount of coloured matter separates out, leaving, 
 on filtration, the liquid in a mucli better condition for examination. 
 
 By treatment of the coagulated residue from the alcoholic ex- 
 traction, the carbohydrate other than sugar — carbohydrate of an 
 amylose natui-e — is obtained, and the process to be adopted is the 
 same as that resorted to for obtaining and estimating the glj-cogen 
 of the liver, viz., dissolving by means of potash, poni'ing into spirit, 
 collecting the precipitate, and subjecting it to the inverting action of 
 sulphuric acid. 
 
 The residue is placed in a flask together with 50 c.c. of a 10 per 
 cent, solution of potash. It is important that the material should 
 have been as thoroughlj- as possible reduced to a minute state of 
 subdivision, in order to secure that none of the nitrogenous matter 
 escapes the action of the potash and remains in a state to give rise, 
 after the subsequent treatment with acid for conversion into glucose, 
 to the biuret reaction when submitted to titration with the copper 
 solution. It is of advantage to allow the mixture to stand for 
 twentj'-four hours in the cold, as greater security is thus given of 
 complete solution being effected by the thirty minutes' boiling .subse- 
 quently resorted to. 
 
 To prevent concentration, through evaporation, of the potash solu- 
 tion, and the po.ssible destruction of the carbohydrate in the process 
 of boiliijg, the operation should be performed in a flask fitted to an 
 inverted condenser, and, in order to e.scape from the inconvenience 
 arising from the frothing which not nnfrequently occurs, a large- 
 sized flask is required. 
 
 The 50 c.c. of liquid are now poured into about 50O c.c. of spirit to 
 separate and precipitate the carbohydrate present. With a smaller 
 proportional amount of spirit, a ri.sk is incurred of the precipitation 
 being incomplete. By setting the beaker aside until the following 
 day, the thorough settlement of the precipitate is promoted, and in 
 this way the subsequent process of separation by filtration facilitated. 
 
 For filtration, a plug of glass-wool should preferably be used. 
 With the employment of filter paper, which is not only constituted 
 of cellulose, but is, moreover, .sometimes found to contain starch, a 
 risk of error is incurred through the possibility of glucose-forming 
 matter being introduced in the subsequent removal, or washing off. of 
 the precipitate. 
 
64 ANALYTICAL RTF.PS OF FIIOCKnUKE. 
 
 Tlio precipitate on the ^'lass-wool is next thoroughly washed with 
 spirit, and the glass-wool plug then turned into the beaker, and the 
 funnel washed with a little hot water. If much water should have 
 been requii-ed for washing off the ])reeipitate, evaporation should be 
 resorted to to bi-ing the bulk down to about 50 c.c. The product, 
 after its transference to a suitable-sized flask, and the addition of 
 sulphuric acid to the extent of 2 per oeiit.. is sul^mitted to the action 
 of heat, according to the directions given further on, for effecting 
 conversion into a cupric oxide reducing sugar. 
 
 A certain amount of undissolved black matter is usually after- 
 wards noticeable, and it is advisable that this should be separated by 
 filtration, before pi'oceeding to neutralisation. Otherwise, it mny be 
 taken up by the potash emploj-ed, and interfere with subsequent 
 titration by giving a more deeply coloured product. The filter used 
 should be small enough to admit of being thoroughly washed with- 
 out undiily increasing the bulk of the liquid. The acid is then 
 neutralised with potash, cautiously added. This leads to a further 
 separation of matter in the form of a dark-coloured, and sometimes 
 bulky, sediment, which should be removed by filtration through a dry 
 filter after the liiptid has been made u]i with water to a definite 
 volume. 
 
 The amount of glucose present is now determined by titration with 
 the ammoniated cupric test, and the resttlt may be either represented 
 as carbohydrate expressed as glucose or brotight by calculation 
 into glycogen- — amylose carbohydrate — figiire.s. The equivalents of 
 glucose and the amylose grotip of carbohydrates corresponding with 
 their accepted formnlse — CeHijOs and CeHmOs — are respectively 180 
 and 162, giving the fraction 162/180, or 0-9, as the multiplier for the 
 conversion of glucose fig'ures into glycogen figures. 
 
 Such is the method of dealing with a flitid animal product like 
 blood. If a solid organ or tissue, such as liver, muscle, &c., is being 
 examined, it is first thoroughly pounded in a mortar, or otherwise 
 minutely divided, and a weighed portion placed in a relatively large 
 quantity of alcohol and well stirred up. After standing for twenty- 
 four hours, the alcohol is strained off through muslin, the residue is 
 pressed, and the extraction and pressing twice repeated in the 
 manner already described. By this process, the sugar present is 
 thoroughly oxtraefed, and separated from the other carbohydrate 
 
GLYCOGEN AND CLEAVAGE CARBOHYDRATE. 65 
 
 matter, wliich remains behind in the residue. The alcoholic extract 
 and the residue are then treated as in the case of blood, for procuring 
 suitable products for examination. 
 
 Until recent investigation taught me otherwise, I was under the 
 impression that the carbohydrate matter obtained by treatment of 
 the residue with potash consisted simply of glycogen. Where 
 glycogen is present, as in the case of the liver, muscle, and certain 
 other constituents of the organism, it enters, it is true, to a greater or 
 less extent into the result; but, as I have shown when speaking of 
 the glucoside constitution of proteid matter, the effect of the action 
 of potash upon proteid is to split off from it carbohydrate material, 
 which passes with the glycogen that may be present, and which, 
 when none is present, I formerly took erroneously to be glycogen. 
 
 Tbe carbohydrate of proteid origin, as I have previously men- 
 tioned (pp. 36, 37), offers much greater resistance than glycogen to 
 the converting action of sulphuric acid. The 2 per cent, strength of 
 acid, which suffices readily to carry glycogen fully into glucose, fails 
 with the body in question to do more than give it about half the 
 amount of cupric oxide reducing power that is given to it by acid 
 of 10 per cent, strength, and even with acid of this latter strength I 
 consider it doubtful whether complete conversion into glucose is 
 effected. It hence happens, in the case of this cleavage carbohydrate, 
 that if the reckoning be applied to it that is applicable in the case of 
 glycogen, an under-estimation of material will result to the extent of 
 about half or, it may be, even more. 
 
 A difficulty is obviously created by this cleavage carbohydrate in 
 the estimation of glycogen as a constituent of the components of the 
 body. As, however, the amount of the cleavage material, given after 
 the employment of 2 jier cent, sulphuric acid as representing glucose, 
 may be computed to stand at not more than about 2 or 3 per 1000 of 
 the fresh tissue examined, it may be considered that where glycogen 
 is present to any significant extent, as may be looked for to be the 
 case with the liver and some other structures, the error introduced 
 does not amount to anything of consequence. 
 
 A point of paramount importance, in connexion with the employ- 
 ment of sulphuric acid for conversion of glycogen, maltose, &c., into 
 glucose, is the necessity of attention being given to secure that 
 the sulphuric acid added remains as free acid in the solution, and is 
 
66 ANALYTICAL STEl'S OF I'KOCEUUKK. 
 
 not appropriatud in neutralising an alkali, oi' in displacing a weaker 
 acid, as where acetic or citric acid has been used and afterwards neu- 
 tralised in some earlier stage of the process. 
 
 As regards the length of time to be employed For conversion, it 
 may be stated that in operating upon starch, glycogen, dextrin, or 
 maltose, it is advisable, in order to be quite safe that full conversion 
 has taken place, to boil for an hour and a half, though probably a 
 shorter time may in reality suffice. An inverted condenser must be 
 used to avoid concentration of the acid liquid, and thereby risk of 
 destruction of tbe product. 
 
 The following observations may be introduced to show the extent 
 of transformation met with after boiling with 2 per cent, acid for 
 successive lengths of time. 
 
 A decoction of starch boiled with sulphuric acid (2 per cent, strength) 
 with the employment of the inverted condenser, and 10 c.c. removed and 
 analysed at the undermentioned periods : — 
 
 Cupric oxide reducing power, 
 expressed as glucose. 
 
 / 
 
 At the end of 
 
 Obs. 1. 
 
 Obs. 2. 
 
 0-200 gram. 
 
 0-140 gram 
 
 0-380 „ 
 
 0-248 „ 
 
 0-B20 „ 
 
 0-264 „ 
 
 0-660 „ 
 
 0-328 „ 
 
 0-660 „ 
 
 0-350 „ 
 
 0-666 „ 
 
 0-350 „ 
 
 0-660 „ 
 
 0-350 „ 
 
 1 „ 
 
 n„ 
 
 2 „ 
 
 3 „ 
 
 A solution of maltose, derived from the action of saliva upon starch, 
 similarly boiled with sulphuric acid, and 10 c.c. removed and analysed 
 
 at the undermentioned periods : — 
 
 Cupric oxide reducing power. 
 At the end of expressed as glucose. 
 
 10 
 
 0-031 
 
 15 
 
 0-031 
 
 30 
 
 0034 
 
 45 
 
 0-041 
 
 
 0-041 
 
 U 
 
 0-041 
 
CONVERSION INTO GLl'COSE. 67 
 
 On looking at the above results, it is observable that in the last 
 experiment conversion was completely effected vrithin tlu-ee-quarters 
 of an hour, whilst in the first two a longer time elapsed before the 
 complete change was found to have occurred. 
 
 With exposure to a higher temperature, a comparatively short time 
 suffices for the complete conversion of starch, glycogen, &c., into 
 glucose. Taking advantage of this fact, I am in the habit of using an 
 autoclave — a boiler constructed for the application of heat under 
 pressure. When used for the purpose referred to, it is set at a 
 pressure equivalent to five atmospheres, which gives a temperature of 
 about 150° C. (300" F.). At this point, the conversion into glucose is 
 accomplished within about a quarter of an hour. It is reliably 
 secured by half an hour, which is the length of time I consider it 
 advisable to allow. 
 
 It is requisite to mention that the presence of sodium sulphate 
 interferes with the inverting action of the acid when the process is 
 conducted under ordinary atmospheric pressure, and that error may 
 thus arise where the inverted condenser is used. Under the higher 
 pressure, however, at which the autoclave is worked, this interference 
 is not, as far as I have perceived, exerted in such a manner as to be 
 noticeable. 
 
 In the case of lactose, one hour suffices for complete conversion 
 into glucose, and may be taken as the time to be allowed. The in- 
 verted condenser must be employed, to prevent concenti-ation by 
 evaporation. The use of the autoclave is inadmissible, on account of 
 its leading to the development of colour in the product. 
 
 With cane sugar, inversion is accomplished within a few minutes. 
 On account, however, of the charring action exerted by sulphuric 
 acid upon cane sugar, citric acid is a preferable agent to use for its 
 inversion. This acid is equally efficacious for the purpose required, 
 and its employment is not attended with the risk of any destruction 
 of carbohydrate. Boiling for seven minutes with a citric acid solu- 
 tion of 2 per cent, strength amply suffices for securing full conversion 
 into glucose. The operation may be conveniently performed in a small 
 open flask, the employment of an inverted condenser being unneces- 
 sary. 
 
 On account of the greater proneness of cane sugar and its deriva- 
 tive invert sugar to undergo destruction by the action of sulphuric 
 
 F 2 
 
68 ANALV'I'ICAL STEl'S OK PKOGEUUKE. 
 
 acid than other carboliydrates, the use of the autoclave should be 
 avoided where the presence of these sugars is suspected. 
 
 Qualilatioc <iiid Quantitative Testhuj. 
 
 Having described the processes by which the carboliydrates exist- 
 ing in animal products are separated from other matters and prepai'ed 
 for the application of testing, I have next to deal with the manner in 
 which the process of testing is conducted. 
 
 The copper test, based on the power possessed by glucose and some 
 other sugars of reducing cupric oxide (CiiO) to the state of cuprous 
 oxide (CujO), affords, I consider, by far the most suitable means of 
 obtaining the information desired, whether of a qualitative or quanti- 
 tative nature. 
 
 The form of copper solution ordinarily employed is a liquid in 
 which cupric oxide is held in solution by alkali through the influence 
 of an alkaline tartrate. The test perhaps in most general use is the 
 liquid known as Fehling's solution, which has the following com- 
 position : — 
 
 Fehlincfs Solution. 
 
 Cupiic sulphate 34G5 grams. 
 
 Potassic sodic tartrate (Rochelle salt) 173'00 „ 
 Caustic soda solution (sp. gr. 1'1200) 600'00 c.c. 
 Distilled water to 1 litre. 
 
 Fehling's solution is, in my opinion, improved by using a larger 
 proportion of alkali than that commonly employed. Thus modified, 
 it is more stable and less liable to give rise to fallacious indications 
 by undergoing spontaneous reduction on boiling. I am accustomed 
 also, on grounds of convenience, to use potash instead of soda. The 
 following is the composition of the liquid I employ : — 
 
 Modified Fehiing's Solution. 
 
 Cupric sulphate 34-65 grams. 
 
 Potassic sodic tartrate (Rochelle salt) 17000 ,, 
 
 Caustic potash 170'00 ,, 
 
 Distilled water to 1 litre. 
 
 It is necessary to bear in mind that these cupric solutions, the 
 
SUGAR ESXnrATION BY GRAVIMETRIC COPPER PROCESS. 09 
 
 latter, however, less readily than the former, undergo, on keeping for 
 some time, especially under exposure to light, change of such a 
 nature as to lead to the spontaneous deposition of some suboxide, and 
 to the deposition of more on boiling. When in a state thus to give 
 rise to the appearance of suboxide precipitate on boiling, the liquid 
 may be restored for a while to its former condition by the addition of 
 alkali. 
 
 Due attention must needs be given to the source of fallacy here 
 presented, and when this is done the test may be regarded as an 
 exceedingly valuable one for the recognition of sugar. 
 
 The test may also be made use of for quantitative purposes, and be 
 thus applied either gravimetrically or volumetrically. Its employ- 
 ment for gravimetric determination is based on the fact that five 
 molecules of cupric oxide are reduced by one molecule of glucose ; 
 and, for volumetric determination, on the fact that the amount of 
 cupric oxide contained in 10 c.c. of the liquid is just I'educed by 
 O'OSO gram of glucose. 
 
 For the gravimetric process, the product to be examined is boiled 
 with an excess of the cupric solution. In the case of blood, &c., the 
 preparation of the product may be conducted by the sodium sulphate 
 method described at p. 59. After full reduction has taken place, 
 the cuprous oxide is collected and may be weighed as such, and the 
 sugar calculated upon the basis of one molecule of glucose for every 
 five molecules of cuprous oxide obtained. 
 
 A better method, on account of its extreme delicacy and precision 
 of dealing with the precipitated suboxide, consists in dissolving it in 
 nitric acid and then submitting the solution to galvanic action in such 
 a manner as to occasion the deposition of the whole of the copper in 
 a pure metallic state upon a weighed cylinder of platinum foil. The 
 weight of the copper is thus readily ascertained and the required 
 calculation made. This process, which I at one time employed when 
 engaged upon a series of comparative observations on the amount of 
 sugar existing in blood taken from different parts of the system, is 
 described in detail in a communication presented by me to the Royal 
 Society in 1877, and contained in the ' Proceedings ' for that year 
 (Vol. 26, p. 314). The results which will be introduced later on will 
 afford evidence of the exactness of the process as a means of sugar 
 estimation. 
 
70 ANAI-YTICAL STF.PS OF PliOCEPURR. 
 
 Holding the position it does, as regards reliability, the electro- 
 gravimetric process is not only of intrinsic value for the purpose of 
 quantitative analysis, but may be considered to possess additional 
 value as a means of gauging the accuracy of other tests. It is, how- 
 ever, a lengthy and, it must be said, a tedious process, and is, on this 
 account, not well adapted for ordinary employment. 
 
 The estimation of sugar gravimetrically through the copper test, 
 by whatever method conducted, is open to the important source of 
 fallacy that if ammonia (whether free or in combination), or a nitro- 
 genous product capable of developing it during the process of boiling 
 with the fixed alkali of the test, is present, error will necessarily 
 follow, in consequence of the solvent action it exerts upon the cuprous 
 oxide, and its eifect in thereby leading to more or less of this product 
 escaping deposition and thus failing to appear in the result obtained. 
 It may be assumed, in the case of the liver, that this in reality occurs, 
 for the figures yielded by the method are so absolutely insignificant 
 and so inconsistently low, compared with those obtained in other 
 ways, that it is evident they cannot be correct. With blood, in a 
 fresh state, I have no reason to think that any such source of fallacy 
 exists. Indeed, the evidence that is presented points to the contrary. 
 In the volumetric method, the estimation is effected by noting the 
 fading and loss of the blue colour of the test solution, as the conver- 
 sion of its cupric oxide into cnproua oxide takes place. The method 
 is a much more expeditious one than the gravimetric, and is not 
 influenced detrimentally by the presence of ammonia. The reckoning 
 is based upon the cupric oxide contained in 10 c.c. being just reduced 
 by 0050 gram of glucose, which is equivalent to saying that the blue 
 colour belonging to 10 c.c. of the solution is just removed by O'OSO 
 gram of glucose. Theoretically, there is nothing to be said against 
 this process ; but, practically, it is found that its application is attended 
 with the disadvantage of the reduced oxide interfering, by remaining 
 suspended in the liquid, with the accui-ate recognition of the terminal 
 point of reduction. For purposes where minute accuracy is not 
 essential, a sufficiently approximate result can be obtained, but for 
 physiological purposes, and in other cases where great precision is 
 required, the process is unsuited for employment. 
 
SUGAR ESTIMATION BY VOr>t'MEl'l;IC COl'PKU PliDf^KSS. , 1 
 
 Quantitative Dt'terminatiou of Suciar by the Ammoniated Viipric Test. 
 
 A test which I introduced about fifteen years ago, and of which a 
 daily experience during the whole of this period enables me to speak 
 with confidence, is not open to the objection above alluded to, and has, 
 moreover, special advantages in other respects, rendering it eminently 
 valuable as an agent for sugar estimation. I refer to the ammoniated 
 cupric test, the principle of action of which is that through the 
 presence of ammonia the cuprous oxide formed by the reducing 
 influence of sugar is held in solution in a colourless state, instead of 
 appearing as a coloured deposit. The progress of the reduction is 
 thus attended with a simple fading of colour, unobscured through- 
 out, and no difficulty is experienced in recognising precisely when 
 the terminal point is attained. 
 
 The ammonia present in the liquid, whilst holding in solution the 
 reduced oxide of copper, does not interfere with the process of reduc- 
 tion. It is incidentally advantageous in deepening the colour of the 
 cupric solution, and thereby increasing the defining capacity of the 
 test, which is proportional to the range of colour passed through. 
 Further — and this is a point of great importance — ammonia confers 
 upon the solution a perfect self-preservative power, the conditions 
 being such that so long as any air is in contact with the fluid, the 
 copper is of necessity kept in a fully oxidised state, and prevented 
 from undergoing deposition. 
 
 The test is an exceedingly delicate one, and is further recom- 
 mended by its readiness and speediness of application. It possesses, 
 indeed, all the delicacy and reliability of the electro-gravimetric 
 process, together with more general applicability, and infinitely 
 greater facility for use. When the two processes are applied side 
 by side, the results yielded are found to stand in the closest agree- 
 ment. It is not too much to say that without the assistance of the 
 ammoniated cupric test I could not have obtained the information 
 which stands at the foundation of this work. 
 
 The following is a description of the mode of preparation of the 
 test liquid, with particulars regarding its position in relation to 
 cupric oxide reduction and sugar oxidation. 
 
 I originally directed that the ammoniated cupric test should be 
 pi'cpared from Fehling's solution, by adding to 100 c.c, of it .'WO c.c. 
 
72 ANALYTICAL STEPS OF PItOCEDUKE. 
 
 of ammonia and 600 c.c. of distilled water ; and, in operating witli tlie 
 liquid, I at first took it for granted that the same relation existed 
 between the amount of oxide of copper reduced and that of sugar 
 oxidised, as under the employment of the copper test of the ordinary, 
 or non-ammoniated, kind, namely, that five molecules of oxide of 
 copper were reduced by one molecule of glucose. The liquid made 
 in this way contained one-tenth of Fehling's solution, and if it com- 
 ported itself in the same manner as the latter, 10 c.c. of it would 
 stand equivalent to 0"005 gram of glucose. In working with it, the 
 results obtained stood in harmonious relation with each other, but 
 when checked by trying it with liquids containing known quantities 
 of sugar it was found that the figures given were invariably too 
 high. At first, I was at a loss to account for this result, but subse- 
 quent observation showed that in the case of the ammoniated liquid 
 six molecules of cupric oxide, instead of only five as with Fehling's 
 solution, are reduced by one molecule of sngar. When the reckoning 
 was made upon this basis, the results exactly corresponded with the 
 actual amounts of sugar known to be present. Moreover, with 
 liquids containing glucose, examined comparatively with Fehling's 
 solution and the ammoniated cupric test containing one-tenth of 
 Fehling's solution, the results stood exactly in accord, under the 
 reckoning that five molecules of cupric oxide in the one case and 
 six molecules in the other were reduced by one molecule of 
 glucose. 
 
 It was further revealed, in the course of the enquiry conducted, 
 that, with the liquid prepared as above from Fehling's solution, the 
 result of titration was to some extent dependent upon the manner in 
 which the product was dropped in from the burette. When the 
 rate of dropping was such as not to involve a prolonged pei-iod of 
 boiling, a correct result was obtained, but when the operation was 
 more slowly performed, evidence was afforded of the occurrence of a 
 certain amount of spontaneous reduction. This is comprehensible 
 from the behaviour of Fehling's solution itself. When in a fresh and 
 not over-dilute state, it does not, even on prolonged boiling, show 
 any sign of the occurrence of reduction, but if brought to a very 
 diliite state, it undergoes, on ebullition, spontaneous change attended 
 with a deposition of suboxide. The ammoniated liquid as compared 
 with Fehling's solution presents consideraMe dilution. It is, there- 
 
AMMONIATED CUPRIG TEST. 73 
 
 fore, not surprising that it should be unable to resist the influence 
 of unduly prolonged ebullition without undergoing spontaneous 
 change. 
 
 In experimenting with the test, it was found that the addition of 
 fixed alkali to the extent of 1 gram of potash for every 20 c.c. had the 
 effect of removing the instability referred to, and of giving to the liquid 
 the power of resisting the tendency to spontaneous reduction under 
 exposure to a prolonged period of boiling. Further investigation 
 showed that a great excess of fixed alkali, such, for instance, as resulted 
 from the addition of 5 grams of potash for every 20 c.c, modified 
 the character of the liquid, and brought it into the same position as 
 the ordinary copper solution, in relation to the number of molecules 
 of cupric oxide reduced by one molecule of sugar ; in other words, 
 that whilst the addition of potash in the proportion of 1 gram for 
 every 20 c.c, and somewhat over this, did not modify the character 
 of the liquid in relation to extent of reduction occurring, the addi- 
 tion of 5 grams to the 20 c.c. so far altered the behaviour of the test 
 that five molecules only of cupric oxide, instead of six, were reduced 
 by one molecule of glucose. With the addition of potash in quanti- 
 ties somewhat under this, the amount of cupric oxide reduced by 
 one molecule of glucose was found to stand between the five and the 
 six molecules. 
 
 To bring the ammoniated copper liquid into a position to repre- 
 sent an exact tenth of the sugar-value of Fehling's solution, the pro- 
 portion of copper requires to be increased so as to give six molecules 
 against five. When this has been done, as by taking 120 c.c. of 
 Fehling's solution instead of 100 for the litre of the ammoniated 
 liquid, the results obtained from titration coincide for the two 
 liquids, and conform with those that are to be looked for when 
 known quantities of sugar, determined by the balance, are employed. 
 When Fehling's solution is used for the preparation of the am- 
 moniated liquid, the required stability, without alteration of sugar- 
 value, is given by doubling the amount of caustic soda present. With 
 the modified Fehling's solution, the composition of which is given at 
 p. 68, and which, for all purposes, 1 consider a preferable liquid for 
 use, the amount of fixed alkali is sufficient to meet what is wanted. 
 
 No need exists, however, to prepare the ammoniated cupric test 
 from either of these solutions, and I never, now, have recourse to 
 
74 ANALYTICAL STEPS OF PKOCEDURE. 
 
 their employment for the purpose. I consider it better to proceed in 
 a direct way, and the following are the quantities to be used : — 
 
 Ammoniated Gupric Te.it Solution. (Pavy.) 
 
 Crystallised copper sulphate 4'158 grams. 
 
 Potassic sodic tartrate (Rochelle salt) . . 20'400 ,, 
 
 Caustic potash 20-400 „ 
 
 Strong ammonia solution (sp. gr. 0'880) 300 c.c. 
 Distilled water to 1 litre. 
 
 In preparing the test, it is found desirable to dissol\re the potash 
 and Rochelle salt together in a portion of the water, and the copper 
 sulphate separately in another. The latter requires the aid of heat 
 for solution. Wh?n completely dissolved, it is poured into the mix- 
 ture of potash and Rochelle salt. 
 
 After the mixed liquids have cooled, the ammonia is added, and 
 then a sufficiency of water to bring up the volume to a litre. 
 
 In sugar-value, 10 c.c. of the liquid stand equivalent to 0005 gram 
 of glucose. 
 
 Such is the theoretical sugar- value of the solution, from the copper 
 present. For many purposes it may be Eccepled as the actual value, 
 but when security of close accuracy is required the liquid should be 
 standardised by means of a solution containing a known quantity by 
 weight of sugar. This I am in the invariable habit of doing when 
 the test is used in conducting physiological investigations. For the 
 purpose, it is best to employ cane-sugar and to convert it into glucose 
 by the agency of an acid. What is sold in the form of coarse colour- 
 less crystals, under the name of " white crystal," and used par- 
 ticularly for sweetening coffee, constitutes a very pure kind of cane- 
 sugar, and therefore an advantageous one to take. It should be 
 reduced to a fine powder, and freed from adherent moisture by ex- 
 posure for a short time in a hot-air oven to a temperature near 
 100° C. (212° F.). Afterwards it may be kept over sulphuric acid in 
 .a desiccator, ready for use at any time. A carefully weighed portion, 
 say ()'250 gram, is subjected to invei'sion by boiling for seven 
 minutes with 50 c.c. of 2 per cent, citric acid This acid is employed 
 in preference to a mineral acid, to avoid any chance of destruction of 
 sugar. When cool, the acid is neutralised with potash, and the 
 
APPLICATION OF AMMONIATED CUPEIC TEST. 75 
 
 volume made up with distilled water to 250 c.c. The liquid is sub- 
 sequently titrated with tlie ammoniated solution, and the value of 
 tlie test calculated from the result obtained. No disparity of any 
 account should be found between the theoretical and the actual 
 value. 
 
 In the employment of the test solution, 10 c.c. and 5 cc. are con- 
 venient quantities to work with, and do not call for the use of any 
 appliance to obviate the inconvenience arising from the evolved 
 ammonia, such as I found to be necessary when I first introduced 
 the test and used a larger quantity for operating with. By diluting 
 the specimen to be examined, as much accuracy is attainable as with 
 the en-jployment of a larger amount of the test and a less dilute 
 product. 
 
 The apparatus best suited for the application of the test consists of 
 a flask of about 150 c.c. capacity, through the cork of which passes a 
 delivery tube from a Mohr's burette, for dropping in the product to 
 be examined, and also an exit tube for the escape of air and steam. 
 The burette is graduated into 20 c.c, each centimeter being divided 
 into tenths, and is fixed in a suitable stand {vide accompanying 
 photo-engraving). Instead of the spring clip commonly used to 
 regulate the dropping of fluid, I employ a screw arrangement, by 
 wliii-li the flow is susceptible of being regulated to a nicety. 
 
7(> 
 
 ANALYTICAL STEPS OF PROCEDURK. 
 
 The product for examination having been introduced into the 
 burette, a little is allowed to escape in order to free the delivery tube 
 
APPLICATION OF AMMONIATED CUPKIC TEST. /7 
 
 from air-bubbles, after which the height of the liquid is read ofif and 
 noted down. The 10 c.c. or 5 c.c. of test liquid, or whatever quan- 
 tity it is intended to employ, are then placed in the flask, and about 
 20 c.c. of distilled water added to increase the bulk to a convenient 
 extent for boiling to be performed. The flask is now affixed to the 
 coi'k belonging to the burette and allowed to hang suspended over 
 the flame of a spirit lamp or Bunsen burner. To facilitate observa- 
 tion of the progress of decoloration, a white background of opal glass 
 is provided. When the contents of the flask have well commenced 
 to boil, the screw which governs the flow from the burette is turned 
 so as to permit the liquid to escape by drops at the rate of about 
 60 to 100 per minute, according to the effect produced upon the 
 colour of the test. What is wanted is a gradually advancing decolora- 
 tion until the contents of the flask are bi'ought to a perfectly colour- 
 less state. Towards the end, the dropping in has to be conducted 
 more slowly than at first, so as to avoid going beyond the exact point 
 required. When decoloration is complete, the flow is stopped. A 
 reading of the level of the liquid in the burette shows the amount of 
 the product which has been used in decolorising the 10 c.c. or 5 c.c. 
 of test solution ; in other words, the amount which contains sugar 
 equivalent in cupric oxide reducing power to 0005 gram or 
 0'0025 gram, as the case may be, of ghicose. 
 
 A basis is thus afforded for ascertaining the amount of sugar con- 
 tained in the entire product, and, as the product represents the 
 weighed material taken for examination, calculation suffices to give a 
 per cent, or per mille expression of the amount of sugar that was 
 present. 
 
 If, in conducting the analysis, the contents of the burette are 
 dropped in too slowly and the boiling becomes prolonged, some sub- 
 oxide may fall in consequence of the expulsion of the ammonia before 
 the operation is completed. Should this occur, a fresh titration must 
 be undertaken, and the contents of the burette dropped in a little 
 more quickly. Any suboxide happening to have been deposited upon 
 the surface of the flask in a previous titi'ation promotes a more 
 speedy deposition of suboxide than would otherwise occur. It must, 
 therefore, be removed by a little nitric or other mineral acid before 
 the flask is again used. 
 
 The chief precautious to be observed in conducting a titration are 
 
VS ANALYTICAL STEPS OF I'ROCEDURE. 
 
 to avoid dropping in the liquid from the burette so rapidly as to incur 
 the risk of running beyond the point required for decoloration, and, 
 at the same time, not to drop in so slowly as to lead to a deposition 
 of suboxide from the expulsion of the ammonia. The liquid should 
 be kept steadily boiling, so that the upper part of the flask may be 
 continuously filled with vapour. An interruption of ebullition would 
 permit the entrance of air, and thereby some possible re-o.xidation of 
 the reduced oxide, which would have to be again reduced before the 
 end of the process, thus leading to a fallacious result. 
 
 With everything conveniently at hand, a few minutes only are 
 required for the performance of the process, from beginning to end. 
 To give precision to the analysis, at least two, and sometimes three 
 or four, titrations are required to be conducted. If the first two 
 titrations yield accordant results, they may be considered to suffice. 
 The first titration, however, is obviously of a somewhat tentative 
 nature, in the absence of any previous knowledge of the quantity of 
 liquid that will be required to be dropped in from the burette. The 
 titrations should be repeated until closely accordant results are ob- 
 tained, the mean of which may be accepted as the final result. 
 
 In first employing the test, the operator must be prepared to find 
 that a certain amount of practice is required to work with it satis- 
 factorily. When, however, the requisite experience has been gained, 
 no difliculty is met with in obtaining precise results. Proof is easily 
 afforded of the pi-ecision of which the test is susceptible by examin- 
 ing two liquids containing different amounts of sugar, and then 
 mixing them in equal proportions and examining the mixture. The 
 flgui-es given by the latter, under experienced hands, and when the 
 liquids used are in a good, colourless state, will be found to exactly, 
 or almost exactly, coincide with the calculated mean drawn from the 
 separate examinations previously conducted. 
 
 As a further illustration of the precision attainable through the 
 medium of the test, I may adduce a few results of duplicate analyses 
 belonging to experiments recently conducted at the Examination Hall 
 Research Labmutories for the purpose of extending and checking my 
 foi-mer woj-k. The results in question serve, it may be remarked, not 
 only to illusti'ate what has been mentioned with regard to the test, 
 but also to show the satisfactory position in which the analytical pro- 
 cedure, taken in its entirety, stands. 
 
ACCURACV OF AMMONIATED CU1'1;IL' TEST. 70 
 
 Duplicate Analyses with thu employment of the Ammoniaied Cnpric Test- 
 
 Sugar per 1000, expressed as 
 
 glucose. 
 
 Duplicates. 
 
 I. Dog's blood from I'ight ventviclo — 
 
 Before sulpliuric acid 0-960 0-940 
 
 After „ 0-920 0-937 
 
 II. Dog's blood from porta! vein — 
 
 Before sulphuric acid 0977 0-943 
 
 After „ MOO 1-070 
 
 III. Dog-'s blood from poi-tal vein — 
 
 Before .sulphuric acid 0968 0-897 
 
 After „ 1-277 1-130 
 
 IV. Dog's blood from portal vein — 
 
 Before sulphuric acid 1823 1-723 
 
 After „ 2-426 2-187 
 
 V. Rabbit's blood from portal vein — 
 
 Before sulphuric acid 1-575 1-630 
 
 After „ 2-085 2085 
 
 VI. Rabbit's muscle — 
 
 Before sulphuric acid 2- 130 2-297 
 
 After „ 3-640 3-743 
 
 VII. Rabbit's muscle — 
 
 Before sulphuric acid 2427 2-570 
 
 After „ 3-640 3-493 
 
 Evidence of a somev hat diiferent nature is also adducible in sup- 
 port of the validity of the results yielded by the process of analysis 
 that has been described. Some years ago I subjected specimens of 
 blood to examination by the electro-gravimetric process, and also by 
 the animoniated cupric volumetric process. The I'esults obtained are 
 recorded in the ' Proceedings of the Royal Society ' for April, 1879, 
 and, although the two processes for the determination of the sugar 
 differ in principle, the one being dependent upon the deposition and 
 collection of the suboxide of copper, and the other upon the reduc- 
 tion being measured by the loss of blue colour accompanying the 
 
80 ANALYTICAL STEP8 OF PROCEDURE. 
 
 transformation of the cupric into cuprous oxide, the figures obtained, 
 a,s will be seen by the subjoined table, present so close a general 
 accord as to mutually confirm the trustworthiness of each other. 
 
 Itestdta from the Analysis of Blood hij the Gravimetric mid the 
 Ammoniated (Jiqjric Volurrwtric Processes. 
 
 Sugar per 1000, expressed as glucose. 
 
 Ciravimetric process. Ammoniated eupric 
 
 Mean of two analyses. volumetric process. 
 
 I. Sheep 0-689 0-571 
 
 II. Bullock 0-735 0-650 
 
 III. Bullock 0-921 0-896 
 
 IV. Sheep 0-533 0567 
 
 V. Bullock O-Sn 0-559 
 
 VI. Sheep 0-631 0-650 
 
81 
 
 INGESTED CARBOHYDRATES TRACED TO TEE 
 PORTAL BLOOD. 
 
 We have next, by the aid of the methods described in the foregoing 
 pages, to follow the main carbohydrates concerned in alimentation, 
 from their introduction into the mouth to their passage, by absorption, 
 into the blood of the portal system, and see what changes occur. 
 Attention will be given to them in the following order : — 
 
 Starch, with its congener glycogen and their derivatives, dextrin 
 
 and maltose. 
 Cellulose. 
 Cane sugar. 
 Lactose. 
 Glucose. 
 
 Starcu, itc. 
 
 Starch enters more largely than any other carbohydrate into the 
 composition of the food of animals, and occupies, on this account, the 
 position of chief importance. Although itself exclusively derived 
 from the vegetable kingdom, it is represented in the animal kingdom 
 by its congener glj-cogen. Glycogen, so far as is to be learnt from 
 the indications of cupric oxide reducing action, comports it.self in its 
 transformations precisely in the same manner as starch, and, since it 
 only occurs to a comparatively insignificant extent as a constituent of 
 food — chiefly in muscular tissue and liver — it will not receive separate 
 attention in the succeeding account of the digestive changes, but must 
 be understood to be included in what is said under the head of starch. 
 As has been previously mentioned, starch exists naturally in the 
 form of a granule, composed of successive laj'ers, of which the outer 
 layer offers great resistance to solvent influences. When the granules 
 are ruptured, however, by the application of heat, an aqueous decoc- 
 tion is obtainable ; but, even in this form, the starch, by virtue of its 
 colloidal properties, is unsusceptible of being absorbed from the 
 
82 INGESTED CAKBOIIYDltATES TiiACED TO POKTAL BLOOD. 
 
 alimentary canal. To be serviceable, therefore, as an alimentary 
 article, starcli must, as a necessary preliminary to absorption, bo 
 brought into a soluble and diffusible form, and this is effected by the 
 process of digestion. Through the influence exerted upon starch in 
 the digestive system, it becomes converted into a form of sugar, with 
 an admixture of the intermediate products of transformation known 
 as dextrins. 
 
 There are various secretions possessing this transformative power 
 over starch — secretions, that is to say, containing an amylolytic 
 ferment. The first with which the food comes into contact is the 
 saliva, a somewhat viscid, slightly alkaline secretion, containing an 
 unorganised ferment known as ptyalin. The extent of the change 
 exerted by saliva is probably small, owing to the incompleteness, as 
 well as the short duration, of the contact between the ferment and 
 the starch. 
 
 Experiments with starch and saliva show that maltose, and not, as 
 was formerly believed, glucose, is the main end product of the action 
 of ptyalin. Apparently, however, a certain, but insignificant, amount 
 of glucose is produced at the same time. As to the precise nature of 
 the changes occurring, and of the intermediate products formed, 
 authorities are at variance, and it is not necessary to enter into tho 
 question of the theoretical mode of splitting up of the starch mole- 
 cule further than has been done in a former part of this work. 
 Broadly speaking, the change may be described as one of increasing 
 hydration, attended with advancing cupric oxide reducing power. 
 
 The action may be studied, and information obtained regarding the 
 general nature of the products, by adding to a decoction of starch a 
 little saliva, and making observations on successive portions taken at 
 short intervals. By means of alcohol the products of transformation 
 may be obtained free from any admixture of untransformed starch, 
 should snch exist; and by subsequent treatment with the ammoniated 
 cupric liquid, before and after boiling with sulphuric acid, the cupric 
 oxide reducing power, as a simple expression, is obtained. In 
 eleven observations that I find recorded in ray laboratory books on 
 mixtures of saliva and starch solution, the cupric oxide redacing 
 power of the respective products varied from 39 to 60, taken in 
 relation to that of glucose reckoned as 100. Thus, in certain cases, 
 conversion of the staxch into maftose had jsractically been accom- 
 
DIGESTION' OF STARCH. 83 
 
 jiiislied, whilst in otliers a large proportion of dextrin, or sometbing 
 with a lower cupric oxide reducing power thai; that of maltose, was 
 still present. 
 
 After the short period of detention that the food undergoes in the 
 mouth, it is propelled along the gullet to the stomach, there to be 
 brought into contact with the gastric juice. 
 
 Acids, as is well known, exert an influence in the direction ol 
 checking the amylolytic action of saliva ; and it is generally asserted 
 that, on the arrival of starch in the stomach, this action is at once 
 stopped by the hydrochloric acid existing in the gastric juice. This 
 statement is not, however, to be accepted too literally or too abso- 
 lutely, for it must be remembered that the gastric juice is not 
 normally produced except in resjionse to the stimulus of the presence 
 in the stomach of extraneous matter, so that food received into a 
 stomach previously empty will not immediately come under the influ- 
 ence of this secretion ; and, during the short interval, whatever may 
 be its duration, which elapses between the entry of food into the 
 organ and the subsequent flow of gastric juice, starchy matters may 
 undergo some further change under the continued action of the saliva. 
 Beyond the interference with salivary action, gastric juice exerts no 
 influence upon starch digestion. 
 
 A power of absorption of diffusible principles is possessed by the 
 lining membrane of the stomach, and, by virtue of this power, what- 
 ever difTnsible matter may have been produced by salivary action 
 stands in a position to pass, at this early stage, into the circulation. 
 That SQch matter is present in considerable amount in the contents of 
 the stomach, after the ingestion of starchy food, is shown by observa- 
 tion. In illustration, I may refer to the results obtained from an 
 examination of the stomach contents of ten rabbits, killed at a period 
 of digestion. In each instance, an alcoholic extract was made, for the 
 purpose of obtaining the transformed carbohydrate matter free from 
 admixture with starch. The examination of the extracts revealed 
 the presence of a considerable amount of carbohj'drate matter possessed 
 of cupric oxide reducing power, varying in the several instances 
 from 25 to 53 expressed in relation to that of glucose taken at 100. 
 In two of the observations, a portion of the contents of the stomach 
 was dealt with at once, whilst another portion was allowed to stand 
 for thirty minutes at a temperature of 48° C, previous to extraction 
 
 G 2 
 
84 INGESTED CAKBOHYDKATES TIIACED TO I'OltTAL I'.LOOD. 
 
 ■witli alcohol. Upon examination, it was found that the cupric oxide 
 reducing power had become raised in the one case from 25 to 48, and 
 in the other from 25 to 50. It thus appears, be the precise cause 
 what it may, that a certain amount of change of carbohydrate may 
 occur under certain conditions, within the stomach. 
 
 From the stomach the alimentary matter, in a semi-fluid condition, 
 is conducted to the small intestine, the part of the alimentary tract 
 which may be regarded as constituting the main seat of starch 
 digestion. It is here brought under the influence of the bile, the 
 pancreatic juice, and the secretions derived from the intestinal walls. 
 Bile, through the alkali contained in it, contributes towards neutral- 
 ising the acidity of the chyme as it passes from the stomach, and 
 thus, indirectly assists in promoting the subsequent digestion of 
 starch by the other secretions ; otherwise little or no action is prob- 
 ably exerted by it upon the carbohydrates. 
 
 Pancreatic juice is an alkaline secretion, possessed of marked 
 power of acting upon starch, its action, like that of saliva, leading to 
 the production of dextrins and maltose. Within the intestinal canal 
 there exist the most favourable conditions for the exercise of the 
 transformative power — for example, intimate contact, alkalinity, and 
 a moderately elevated temperature — and, accordingly, the conversion 
 of stai'ch begun in the mouth is now carried on with its highest 
 degree of activity. The process of transformation and the nature of 
 the products formed may be studied in a similar manner to that 
 mentioned in the case of saliva. The results of ten experiments 
 with starch and pancreatic ferment derived from the sheep, the cat, 
 and the dog, showed the attainment of cupric oxide reducing power 
 ranging from 23 to 60, expressed in relation to glucose taken at 100. 
 Thus in some cases complete conversion into maltose had practically 
 been accomplished, whilst in others the product must have consisted 
 largely of dextrin. 
 
 The efl'efit of the presence of acid or of carbonated alkali is to 
 modify the action of the amylolytic ferments, whether pancreatic or 
 salivary. For instance, the addition of sodium carbonate seems to 
 determine the formation of a final product with a lower cupric oxide 
 reducing power than that which would otherwise be obtained. The 
 change is prevented from passing beyond a certain point more or 
 less short, apparently according to the amount of sodium carbonate 
 
DIGESTION OF STARCH. 
 
 85 
 
 nsed, of the productiou of maltose. This is shown by the subjoined 
 observations. 
 
 100 c.c. of a decoction of starch -were mixed with 60 c.n. of an 
 aqueous extract of pancreas, and exposed to a temperature of 48° C. 
 10 c.c. portions were removed at the undermentioned periods, and 
 the cupric oxide reducing power of each taken. Parallel experi- 
 ments were made with the addition of 2 grams and 4 gi-ams (giving 
 the respective percentages of I'S and 2-6) of carbonate of soda. The 
 cupric oxide reducing power, expressed as glucose, was found in the 
 several instances to stand as follows : — • 
 
 10 c.c. portions 
 after 
 
 Sugar found, expressed as glucose. 
 
 Without 
 
 With 1-3 per 
 cent, of Na-jCOj. 
 
 With 2-6 per 
 cent, of NaoCO,. 
 
 15 minutes 
 
 30 
 
 0-015 gram 
 0-018 „ 
 0-018 „ 
 018 „ 
 
 -OOG gram 
 009 „ 
 -009 „ 
 -009 „ 
 0-009 „ 
 
 0-005 gram 
 -009 „ 
 0-009 „ 
 008 „ 
 0-009 ,. 
 
 45 „ 
 
 1 hour 
 
 2 hours 
 
 
 A similar e.^cperiment was upon another occasion performed with a 
 different decoction of starch and aqueous extract of pancreas. The 
 following, expressed as before, were the results obtained : — 
 
 10 c.c. portions 
 after 
 
 Sugar found, expressed as glucose. 
 
 Without 
 NaoCOj. 
 
 With 1-3 per 
 cent, of NaoCOj. 
 
 With 2-6. per 
 cent, of NajCOa. 
 
 15 minutes 
 
 30 
 
 -031 gram 
 -046 „ 
 047 „ 
 0-046 „ 
 
 -013 gram 
 0-014 „ 
 0-014 „ 
 0-014 ., 
 
 0-009 gram 
 010 „ 
 0-010 „ 
 0-010 „ 
 
 45 
 
 
 
 Acids, as already mentioned with reference to saliva, exert a re- 
 tarding or an actually preventive influence on the action of these 
 ferments upon starch. The presence of even an organic acid, such as 
 
86 
 
 INGESTED CARBOHYDRATES TRACED TO PORTAL BLOOD. 
 
 citric, whilst not wholly preventing the transformation, exerts a 
 mai-ked degree of interference with such change, and determines the 
 non-conversion of a considerable quantity of starch. 
 
 The following results of experiments made with starch solution 
 and aqueous extract of the pancreas of a dog, will serve to show the 
 influence exerted by citric acid and sodium carbonate respectively on 
 the process of transformation. 
 
 30 c.c. of a solution of starch were placed in contact with 5 c.c. 
 of the pancreatic extract and allowed to stand for 18 hours at the 
 ordinary temperature. At the end of that time an alcoholic extract 
 was made, and the sugar determined before and after treatment with 
 sulphuric acid. A parallel procedure was adopted with the additior, 
 in the one case, of 05 gram (1"4 per cent.) sodium carbonate, and, in 
 the other, the same quantity of citric acid. The results obtained 
 stood as follows : — • 
 
 Eelation of the 
 
 cuprio oxide 
 
 Sugar produced, reducing power 
 
 expressed as of the product 
 
 glucose in to that of 
 
 grams. glucose at 100. 
 
 Experiment I. 
 
 After action of ferment J before sulphuric acid . . '074 I ,„ 
 
 alone Rafter „ „ .. 0-156 J ' 
 
 After action of fcrmeutT 
 
 in presence of 1-4 [before sulphui'ie acid . . 0'034 XvR 
 
 per cent, sodium car- | after ,, ,, •• 0'130 J 
 
 bonate J 
 
 After action of ferment "| 
 
 in presence of 1'4 I before sulphuric acid , . trace 1 
 
 per cent, of citric f after „ „ .. 0'058 J 
 
 acid J 
 
 Experiment II. 
 
 After action of ferment f before sidpluu'ic acid . . 070 \ ^, 
 
 alone "[after „ „ .. 0-138 J 
 
 After action of ferment "l 
 
 in presence of 1'4 I before sulphiu'ic acid . . '034 "I ,„ 
 
 per cent, of sodium 'after ,, ,, •• 0'148 /" 
 
 carbonate J 
 
 After action of fermeutT 
 
 in presence of 1 '4 I before sulphui'ie acid . . 032 "I „„ 
 
 per cent, of citric | after ,, u •• 096 J 
 
 acid J 
 
DIGESTION OF STARCH. 
 
 87 
 
 Experiment III 
 
 After action of fcnuent f before sulpluirie acid 
 
 alone \ after ,, 
 
 After action of ferment 1 
 
 in presence of 14 I before sulplmric iicid 
 
 per cent, of sodium | after ,, 
 
 carbonate J 
 
 After action of ferment"] 
 
 in presence of 1'4 [before sulphuric acid 
 
 per cent, of citric [after ,, 
 
 acid J 
 
 Sugar produced, 
 
 expressed as 
 
 glucose in 
 
 grams. 
 
 Kelation of the 
 cupric oxide 
 
 reducing power 
 of the product 
 
 to that of 
 glucose at 100. 
 
 III. 
 
 
 I.. 0-07 -4 
 .. 0-322 
 
 J23 
 
 1.. 0-084 
 .. 0-274 
 
 jao 
 
 1 .. 014 
 .. 0-038 
 
 ]n 
 
 Experiment IV. 
 (In this instance glycogen was substituted for starch ) 
 
 After action of ferment J before sulphuric acid .. O'llfi 1 ,„ 
 
 alone latter „ „ .. 0-238 J 
 
 After action of ferment 1 
 
 in presence of 14 ( before sulphuric acid . . 0-004 1. 04, 
 
 per cent, of sodium falter „ „ •• 384 J " 
 
 carbonate J 
 
 After action of ferment ~| 
 
 in presence of ] 4 [before sulphuric acid . . '016 \ «;7 
 
 per cent, of citric (after „ „ .. 0-028 J ' 
 
 acid J 
 
 The other secretions pertaining to the intestine are those derived 
 respectively from the glands of Bruuiier and the glands of 
 Lieberkiihn. 
 
 The secretion of the glands of Brunner, glands special to the 
 duodenum or first portion of the intestine, probably operates in the 
 same vray as that of the pancreas in relation to starch digestion ; but, 
 from the anatomical situation of the glands, their secretion cannot 
 properly be isolated, and therefore nothing definite has been ascer- 
 tained with regard to it. 
 
 On the other hand, the succus entericiis or intestinal juice, produced 
 by the glands of the intestine, called glands of Ldeberkiilin, has been 
 ascertained to have a definite action upon starch, which differs from 
 that of the salivary and pancreatic secretions in possessing a glucose- 
 forming capacity. Under the influence of this secretion, starch is 
 
88 IXGESTED CARBOHYDRATES TRACED TO PORTAL BLOOD. 
 
 carried througli a succession of products possessing an increasing 
 cupric oxide reducing power; but the change does not, as in the 
 case of the salivary and pancreatic ferments, stop at the stage of 
 maltose. If a large amount of the ferment be used, and the action 
 continued for some time, the process of transformation may be found 
 to proceed actually to the production of glucose. Apparently the 
 change is a gradual and continuous one, without any definite halt or 
 interruption ; and the point of termination seems to depend upon the 
 amount of ferment and the time during which it is allowed to act. 
 We have here, therefore, under suitable conditions, a glucose-forming 
 ferment to deal with ; but the final cupric oxide reducing power pre- 
 sented by a product may stand at any point between maltose and 
 glucose or short of maltose. 
 
 The following observations show the results obtained from sub- 
 mitting starch to the action of the ferment existing in the intestine : — 
 Some starch decoction was mixed with a large quantity of sheep's 
 intestine, and exposed for three hours to a temperature of 48° C. A 
 portion was examined at the end of the three hours, and it was found 
 that a product existed with a cupric oxide reducing equivalent of 50 in 
 relation to glucose at 100. The remainder was allowed to stand for 
 twenty-four hours. The cupric oxide reducing power was then found 
 to have been raised to 85. 
 
 Some starch decoction mixed with a large quantity of rabbit's in- 
 testine was exposed to a temperature of 48° C. for three hours, and 
 then allowed to stand aside for twenty hours. At the end of the 
 three hours, the product possessed a cupric oxide reducing power a 
 little above that of maltose. At the end of the twenty hours, glucose 
 existed. 
 
 Some starch decoction, mixed with a large quantity of rabbits' in- 
 testine, was exposed to a temperature of 48° C. for three hours, and 
 then set aside for twenty-four hours. After the three hours' exposure 
 to 48° C, the cupric oxide reducing power was found to be 87. After 
 the subsequent twenty-four hours, it stood at 98. 
 
 Some starch decoction was mixed with a watery extract of cat's 
 intestme, and the mixture left for eighteen hours at the ordinary 
 temperature. The cupric oxide reducing power was then found to be 
 91. 
 
 The intestinal mucous membrane is found (o retain its transforma- 
 
PRODUCT OF STARCH DIGESTION IX PORTAL BLOOD. 89 
 
 tive power after having been dried, provided tlie drying lias been 
 effected at a temperature insufficient to lead to the destruction of the 
 ferment. Of seven experimental observations, conducted with the 
 dried intestine of the horse and a solution of starch, two yielded re- 
 sults, showing that the sugar produced consisted of glucose. In the 
 other five, the extent of transformation fell more or less short of this, 
 the cupric oxide reducing powers of the several products being repre- 
 sented by the numbers 71, 79, 80, 81, and 86, in relation to that of 
 glucose taken at 100. The temperature employed was 38° C, and the 
 period of exposure to it varied from thirty minutes to four hours. In 
 one of the two cases, in which the product was found to consist of 
 glucose, the mixture had simply been set aside for twenty-four hours 
 at the ordinary temperature. 
 
 These observations suffice to show that a ferment exists in the walls 
 of the intestine which has the power of carrying the process of 
 transformation on till glucose is reached. The process passes on 
 gradually through successive stages marked by advancing cupric 
 oxide reducing power. It is evident, however, from the observations 
 to follow, that glucose is not to any large extent produced by the 
 action of the secretions within the alimentary canal, whatever may be 
 the ferment power existing in the intestinal walls themselves. 
 
 The contents of the intestine were examined in five rabbits, taken 
 at a period of digestion. The rabbits had been fed in three of the 
 instances on oats and green food, and in the other two on oats 
 moistened with water. An alcoholic extract was made so as to 
 separate the transiormed from the untransformed starch. The cupric 
 oxide reducing power of the product obtained was in every case below 
 that of maltose, and where the food had consisted of moistened oats, it 
 was lower than in the others. 
 
 Product of Starch Digestion fowid in the Portal Blood. 
 
 We are now brought to the consideration of the question of the 
 precise form in which the changed starch reaches the portal blood, as 
 revealed by observation conducted upon the blood itself. The point 
 touches the practical issue of starch digestion. I have performed a 
 large number of experiments upon the subject. The detailed results 
 will be introduced under the general consideration of the portal blood 
 (pp. 105 — 106). All that is necessary here to state is that a sig- 
 
90 IKGESTED CAKBOHYDEATES TltACKD TO PORTAL BLOOD. 
 
 nificant, and often even a very notable, amount of sugar is discoverable 
 in the portal blood as the effect of the ingestion of starchy matter ; 
 and that the sugar in its totality has a cupric oxide reducing power 
 varying between that of maltose and that of glucose, thus showing 
 that, whether glucose is present or not, sugar other than glucose must 
 to a greater or less extent exist. 
 
 Cellulose. 
 
 Cellulose is characterised by its resistance to solution by ordinary 
 solvents. Little of a definite nature is known about its solution in 
 the alimentary canal of animals. Probably in the human subject but 
 little cellulose is digested and absorbed. In some of the herbivorous 
 animals, however, notably in the large group of grass and hay feeders, 
 it enters to so large an extent into the food that the capacity for 
 digesting and rendering it of alimentary value may be inferred to 
 exist. This inference is supported by the proof that can be adduced 
 from the vegetable kingdom of cellulose being susceptible of under- 
 going transformation and solution by the action of certain kinds of 
 ferments. Thus, to quote from Sachs* : — 
 
 " The non-nitrogenous reserve material [in the stone of the date] 
 consists of hard cellulose, which is deposited in the endosperm in the 
 form of thickened cell walls, and which constitutes the great mass of 
 the date stone. The embryo, at first very minute, protrudes its root 
 and plumule at the beginning of germination, and only the upper- 
 most portion of the primary seed leaf, which now gradually develops 
 into a cup-shaped absorbing organ, becoming larger and larger, re- 
 mains within the endosperm. This organ consists of a very delicate 
 parenchyma, and excretes ferments which dissolve the hard endo- 
 sperm in its immediate neighbourhood. The products of solution are 
 absorbed by the organ and then conveyed into the growing parts of 
 the seedling ; until, finally, the whole of the hard date stone is dis- 
 solved and its cavity occupied by the developed absorbing organ. 
 The seed of PhytelepJias (known under the name of vegetable ivory), 
 which is at least a hundred times larger than the date stone, and the 
 
 * ' Lectures on the Physiology of Plants.' By Julius von Sachs : Translated by 
 H. Marshall Ward; Clarendon Press, Oxford, 1887. 
 
DIGESTION OF CELLULOSE. 91 
 
 endosperm of which, consists of much harder cellulose, behaves 
 similarly. 
 
 " The action of those fungi which destroy wood and kill trees may 
 be compared directly with the action of such seedlings on their endo- 
 sperm ; the thin mycelial threads of these fungi, as has been shown 
 by Robert Hartig in his magniBcent work, penetrate into the al- 
 burnum and heart wood of trees, evidently because they excrete 
 ferments at their growing apices, which dissolve the hard cell-walls 
 of the wood." — (p. 3ii.) 
 
 With a suitable ferment present, there is no reason that cellulose 
 should not be susceptible of undergoing digestive solution by trans- 
 formation into sugar, and of being thereby placed in a position to 
 prove of equal alimentary value to starch or any other carbohydrate. 
 A more or less considerable disappearance of cellulose has been 
 ascertained to take place in the digestive tract, especially of herbi- 
 vorous animals, which stands in harmony with the hypothesis 
 suggested. But it must be stated that no specific celluloljtic fer- 
 ment belonging to the alimentary canal has yet been recognised, and 
 the proposition has been advanced that the disappearance of cellulose 
 may be in part accounted for by a transformation of an altogether 
 different kind. Under the influence of putrefactive action cellulose 
 may be broken up, with the evolution of marsh gas as a product, and 
 it has been pointed out that during the detention of the alimentary 
 m.atter in the very voluminous ciBCum of some of the herbivora marsh 
 gas is to a certain extent developed. 
 
 Cane Sugak. 
 
 Cane sugar, considered as an article of food, is, on account of its 
 ready solubility and diffusibility, in a position widely different from 
 that held by starch, glycogen, and cellulose. As far as its physical 
 properties are concerned, it is, therefore, in a state to be susceptible 
 of absorption from the alimentary canal, without requiring any pre- 
 paratory process of digestion. It does not, however, follow from this 
 that it becomes absorbed and reaches the portal system without un- 
 dergoing alteration. This is a point to which attention will be given 
 after certain preliminary considei-ations have been disposed of con- 
 
f>2 INGESTED CAIiBOIIYDRATES TKACED TO POIITAL HLOOD. 
 
 rerning the chemical relations of cane sugar, and the methods em- 
 ployed in its estimation. 
 
 Cane sugar does not possess any cnpric oxide reducing power, but 
 like the other carbohydrates is converted into glucose by boiling 
 with dilute sulphuric acid, the change in the case of cane sugar 
 being known as inversion, and its product, as invert sugar. Invert 
 sugar is in reality a mixture, in equal quantities, of two fonns of 
 glucose — dextrose and Irevulose, each of them possessing the cnpric 
 oxide reducing power belonging to glucose derived from other sources. 
 A ready means of effecting a quantitative estimation of cane sugar is 
 thus afforded, it being only necessary that the sugar should be sub- 
 jected to inversion, and the cupric oxide reducing power of the 
 product determined. From this, an expression of the amount of 
 cane sugar is obtainable by calcalation. The relation existing be- 
 tween cane sugar and glucose gives as the factor for convert- 
 ing glucose figures into figures representing the corresponding 
 
 amount of cane suo-ar, the expression, l\ — : ) or 0'95. 
 
 "^ ' \oG0/ 
 
 Thus :— 
 Amount of invert sugar (glucose) x 095 = Amount of cane sugar. 
 
 For conversion of cane sugai' into glucose by boiling with sulph- 
 uric acid, a 2 per cent, solution of acid is n.sed, as for the other 
 carbohydrates ; but the time required for the completion of the 
 process is much shorter than that needed for the other bodies. Full 
 conversion may, in fact, be reckoned to have taken place after boiling 
 fur five minutes. I have indeed observed that three minutes have 
 sufficed. The boiling should not be continued beyond the point which 
 will reliably secure complete conversion on account of risk of 
 destruction and the development of colour which would interfere 
 with the subsequent process of titration with the copper test. It 
 may happen that no colour is perceptible at the end of an unneces- 
 sarily prolonged boiling, and yet that more or less colour appears 
 when the acid is neutralised. 
 
 Cane sugar is, however, convertible into glucose, not only by the 
 mineral acids but also by dilute organic acids, and citric acid is a 
 convenient — indeed, I consider, the most convenient — agent for em- 
 ployment for the purpose. A 2 per cent, strength suffices, and seven 
 minutes are sufficient to allow for the period of boiling. No risk is 
 
CAXE SUGAR IX DIGESriVE SVSTEM. S.'-i 
 
 involved of the production of colour or the oacurrence of any destruc- 
 tion. Cane sugar in this respect differs from starch and glycogen 
 and the various products emanating from them. None of these 
 bodies, as I have satisfied myself by direct observation, are affected 
 by boiling with citric acid. 
 
 By taking advantage of tbis property, it becomes practicable to detect 
 and estimate cane sugar in the presence of other bodies (lactose ex- 
 cepted) of the carbohydrate group. The method of procedure consists 
 in dividing the solution to be examined into two equal portions. One 
 portion is titrated at once, and the cupric oxide reducing power belong- 
 ing to the product ascertained. The second portion is boiled with citric 
 acid (added in proportion to give a 2 per cent, solution), neutralised, 
 and then titrated. An identity between the two results is indicative 
 of an absence of cane sugar. An increase, on the other hand, 
 noticeable after treatment with the acid denotes the presence of cane 
 sugar, and affords a measure of its amount. 
 
 It should be mentioned that in all investigations involving the 
 question of the transformation of cane sugar it is necessary to be sure 
 that the specimen employed exerts no cupric oxide reducing action. 
 Specimens often contain more or less glucose as an impurity, and 
 vitiated results may thus be given. The sugar sold in coarse, 
 colourless crystals — that which is known as " white crystal " and is 
 used for sweetening coffee — may be instanced as being of the requisite 
 purity. No cupric oxide reducing power existing at starting, what- 
 ever cupric oxide reducing power is subsequently met with may be 
 read as affording a measure of the amount of cane sugar that has 
 undergone transformation. 
 
 With these pi'eliminary remarks we may now follow the cane sugar 
 after its ingestion. 
 
 Cane sugar taken into the mouth undergoes no change before 
 reaching the stomach. I have submitted the point to actual observa- 
 tion, and my observations, in accordance with what is commonly 
 stated, have furnished no evidence that any action is exerted upon 
 cane sugar by saliva, and I may here further state that the same 
 holds good with regard to the pancreas. 
 
 Some confusion exists with regard to what occurs in the stomach 
 in relation to cane sugar. The general belief, expressed in broad 
 terms, is that cane sugar is not acted upon to any extent by the 
 
!)4 INVESTED CAKBOHYLiKATES TKACED TO I'OKTAL BLOOD. 
 
 stomach, but that in the intestine it comes into contact with a 
 ferment which transforms it into invert sugar. Neither of these 
 statements must be taken as literally and wholly correct. Observa- 
 tions I have conducted have shoven, in the first place, that a ferment 
 exists in the stomach-walls capable of producing a certain small 
 amount of ti-ansformative effect ; and, in the second, that although 
 the intestine of animals generally possesses an active transformative 
 power, in the ruminant such is not the case. In this class of 
 animals the transformative power is located in certain portions of the 
 stomach. 
 
 The subjoined experimental evidence, obtained from various 
 animals, shows in a decided manner that a certain amount of trans- 
 formative power is, as a general condition, possessed by the stomach 
 as well as by the intestine. It is true, the power in the intestine is 
 very much greater than that in the stomach. This will be seen from 
 the quantitative results to be adduced. In the case of the intestine, 
 the transformative energy is sufficiently strong to produce an effect 
 that is readily perceptible through rough qualitative testing. In the 
 case of the stomach, however, the effect might easily be overlooked if 
 a more delicate method of procedure were not adopted. The follow- 
 ing are the results, briefly expressed, of some of the experiments I 
 have conducted. 
 
 A solution of cane sugar was introduced into the thoroughly 
 cleansed stomach of a recently killed rabbit. The stomach, ligatured 
 at its two orifices, was then placed in a beaker of water, and, after 
 being exposed for thirty minutes to a temperature of 48° C, was set 
 aside in the laboratory for twenty-four hours. At the end of this 
 time a considerable amount of sugar had diffused through the 
 stomach-walls, and was to be found in the surrounding water. Ex- 
 amination showed that 9 per cent, consisted of glucose. Analysis of 
 the liquid remaining in the stomach showed the presence of glucose 
 to the extent of 24 per cent, of the sugar found. 
 
 A coil of intestine was dealt with in a similar way. At the end of 
 the twenty-four hours, examination showed that 40 per cent, of the 
 sugar contained in the diffusate, and 30 per cent, of that present in 
 the contents of the intestine consisted of glucose. In a duplicate 
 experiment with the intestine, 53 per cent, of the diffused, and 45 per 
 cent, of the undiffused, sugar consisted of glucose. 
 
CAN'E SUG.VI! IN' DIGESTIVE SVSTE.M. 95 
 
 It will be noticed in the above experiments tliat, on tlie one hand, 
 a certain amount of sugar bad passed tkrough the membi'anous 
 medium in an untransformed state, and that, on the other, a certain 
 amount of transfurmed sugar was encountered in the uudift'used 
 liquid. 
 
 In other experiments, scrapings from the mucous membrane of the 
 stomach and the intestine were placed in contact with a solution of 
 cane sugar, and exposed to conditions favourable to ferment action. 
 With the intestine, in the case of the rabbit, pig, horse, dog, and cat, 
 a marked transfoi-mative action was found to be exerted, whilst in 
 the case of the ruminant an absence of effect was observed. With 
 the stomach (the stomach of the ruminant will receive separate con- 
 sideration later on), there appeared to be evidence of a certain, 
 though comparatively insignificant, amount of transformation, the 
 evidence being more decided in the case of the pig than in the other 
 animals. 
 
 The mucous membrane not only possesses transformative power 
 in its fresh state, but also after having been kept. Indeed, the 
 setting in of decomposition appears to lead to the production of an 
 increased transformative energy. The follow'ing experimental results 
 may be adduced in support of this statement : — ■ 
 
 25 grams of fresh rabbit's intestine were mixed with 05 gram 
 of cane sugar dissolved in 60 c.c. of water, and allowed to stand for 
 15 minutes at 38° C. The product obtained by subsequent treat- 
 ment with sulphate of soda contained 0'126 gram of transformed 
 cane sugar. In corresponding experiments, made with the same 
 rabbit's intestine which had been previously allowed to remain 
 exposed to the air for periods of 24, 72, and 96 hours, the amounts of 
 glucose found were respectively 0'363, 0405, and 0'312 gram. 
 Another 25-gram portion of the intestine was allowed to stand for 
 120 hours, and was then mixed with only half the quantity of sugar 
 previously employed. After proceeding as in the other experiments, 
 examination of the product showed that the whole of the sugar 
 present existed in the form of glucose. 
 
 Alcohol precipitates the ferment without destroying its activity. 
 The precipitated material, dried at a suitably moderate temperature, 
 may be kept, and will be found to retain its virtue for an indefinite 
 period. I have recently experimented with a specimen, derived 
 
90 IXGKSTED CAKlidHVOltATES TRACED 'lO PORTAL P.LOOIi. 
 
 from the mucous membrane of the horse, which has been kept for 
 four years. It yielded the following evidence of activity : — 
 
 30 grams of the dried substance in a powdered state were mixed 
 ■with 5 grams of cane sugar dissolved in 100 c.c. of water, and kept 
 at a temperature of about 38° C. 20 c.c. portions were removed at 
 intervals and examined. At the end of 1^ hours it was found that 
 17 per cent., at the end of 4^ hours 32 per cent., and at the end of 
 21 hours (during the latter part of the time the temperature had 
 fallen to 26° C.) 72 per cent, of the sugar present consisted of glucose. 
 
 The ruminant animal, as has already been stated, stands in a 
 position different from that of animals generally, in relation to the 
 point under consideration. The intestine possesses only an insignifi- 
 cant amount of transformative energy. The effect produced upon 
 cane sugar by its mucous membrane is about comparable to that 
 which I have described as produced by the stomach of other animals. 
 A compensatory action is exerted elsewhere. The reed, or fourth 
 division, is the portion of the ruminant stomach which represents the 
 ordinary stomach ; and, in harmony with this, it is found that only 
 an insignificant power of transforming cane sugar is possessed by its 
 mucous coat. In connexion, however, with the other portions, a 
 more or less marked transformative energy is shown by observation 
 to exist. The following stands in illustration of what I have 
 stated. 
 
 Portions of the cleansed paunch, reticulum, manyplies, reed — or 
 true stomach, and intestine of a sheep, were minutely divided, and 
 10-gram quantities of each taken. After the addition of a little 
 water, they were severally mixed with 5 c.c. of cane sugar solution, 
 containing the equivaleflt of 0'104 gram of glucose, and exposed 
 for two hours to a temperature of 48° C. Subjoined are the re- 
 spective amounts of glucose that were found to be present : — ■ 
 
 Paunch 0086 gram. 
 
 Reticulum 0-020 „ 
 
 Manyplies 0-068 „ 
 
 Reed, or true stomach .... O'OIG ,, 
 
 Intestine a trace. 
 
 Other observations have been conducted, and though the figures 
 obtained have not uniformly held the same relation, a general agree- 
 
CANE SUGAR IN DIGESTIVE SYSTEM. 97 
 
 ment with those given above has been noticeable. The paunch and 
 nianyplies have given evidence of possessing more transformative 
 energy than the reticulum, and the reticulum than the true stomach. 
 The experimental evidence adduced in the preceding text has 
 shown that the walls of the stomach possess a certain, though slight, 
 power of inverting cane sugar. The enquiry hitherto has only 
 touched the eifects producible by the structural parts of different 
 portions of the alimentary canal. Another point that presents itself 
 for investigation is whether any effect is produced within the stomach 
 by the action of the contents at a period of digestion. I have made 
 a number of experiments upon this point, and will give, as examples, 
 the results obtained in some of them. Evidence, it will be seen, is 
 afforded of the occurrence of a marked amount of transformation. 
 
 A dog was fed upon meat, and, during digestion, 30 grams of cane 
 sugar in solution were injected into the stomach through a tube 
 passed down the oesophagus. Twenty minutes later the animal was 
 killed. The liquid contents of the stomach were collected and ex- 
 amined. In a total of 7"500 grams of sugar found to be present, 
 0'600 gram existed in the transformed state. The contents of the 
 intestine were also examined, and it was found that in a total of 
 1'470 grams of sugar rather less than half consisted of glucose. 
 
 A solution containing 28 gi'ams of cane sugar was given to another 
 dog, which had been fed with meat four hours previously. The 
 animal lapped the liquid out of a vessel. Twenty minutes afterwards 
 it was killed. Of the 6'492 grams of sugar found in the liquid 
 portion of the stomach-contents, I'OSl gr-ams, or about one-sixth, 
 consisted of glucose. In the intestinal contents, taken for examina- 
 tion, the sugar found amounted to 0'645 gram, of which 0'244' gram 
 consisted of glucose. From the figures thus yielded in this and the 
 preceding observation, evidence is presented that cane sugar, to a 
 greater or less extent, reaches the intestine in an untransformed 
 state, and therefore, in part, escapes absorption by the stomach. 
 
 In the observations just referred to, the sugar was introduced info 
 the stomach of the living animal. The effect has also been ascer- 
 tained of bringing cane sugar into contact with the contents of the 
 stomach outside the body. In the observations conducted, the con- 
 tents of the stomach of rabbits were employed, and exposure for 
 half an hour to a temperature of 48° C. allowed. The sugar was then 
 
98 INGESTED CARCOIIVDRATES TRACED TO I'ORTAL BLOOD. 
 
 extracted with alcohol, to eliminate from the product the starchy 
 matter present. From a comparison of the figures representing the 
 amounts of sugar found before and after inversion with those repre- 
 senting the sugar contained in a corresponding amount, similarly 
 dealt with, of the stomach-contents taken alone, evidence was 
 affoi'ded of an extensive transformation of cane sugar having in each 
 instance taken place. In one of the experiments the whole had 
 become transformed. 
 
 The effect of what has preceded is to show that when cane sugar 
 is brought into contact with the contents of the stomach, whether 
 within the living animal or not, a marked extent of transformation 
 into glucose occurs. That such a result should ensue is only in 
 accord with what might be expected, seeing that dilute acids have 
 the power of inverting cane sugar, even at moderate temperatures. 
 This I learnt in the course of my experiments, and the fact has not 
 escaped the notice of others. To show the kind of effect produced, 
 I may give the following particulars of two observations on the 
 point: — 
 
 1. A liquid containing 3 drops of hydrochloric acid in 100 c.c. of 
 
 water was placed iu contact with 5 grams of cane sugar and 
 kept at 38° 0. 20 c.c. portions were removed at the end of 
 five, and of twenty-four, hours. The amounts of invei-t sugar 
 respectively found in them were 0157 and 0392 gram. 
 
 2. A solution of citric acid, to represent an organic acid, of 5 per 
 
 cent, strength was, in the other case, used, and the same 
 method of procedure as in the previous observation adopted. 
 The 20 c.c. portions removed at the end of five and of twenty- 
 four hours respectively contained 0'112 and 0326 gram of 
 invert sugar. 
 
 Product derived from Ingested Cane Sugar found in the Portal Blood. 
 
 The next matter for consideration is one which stands as the main 
 point of physiological interest jind importance in connexion with the 
 ingestion of cane sugar, viz., the form of sugar which actually reaches 
 the portal blood. 
 
 Careful experimenting is required in order to obtain the desired 
 information, and it is necessary, iu the first place, to have a know- 
 
LACTOSE IN DIGESTIVE SYSTEM. 99 
 
 ledge of the condition natural to the portal blood apart from the 
 ingestion of cane sugar. This constitutes the basis for the interpre- 
 tation of the results obtained after its ingestion. Later on, attention 
 will be given to the state of the portal blood under various conditions 
 (vide p. 101, tt seq.), and it will be advisable to defer till then 
 entering into detailed considerations of its condition after the inges- 
 tion of cane sugar. It will here be sufficient to state that an increased 
 amount of sugar is met with, and that glucose is the form of sugar 
 present. In my own experiments no indication has been afforded of 
 the passage of cane sugar, as such, into the portal blood, but the 
 statement is made that after the ingestion of large amounts of cane 
 sugar traces may be found both in the blood and the urine. I learnt 
 from observations (vide p. 116) conducted many years ago, that, 
 under the circumstances named, glucose in notable amount became 
 discoverable in the urine, but it did not occur to me to examine and 
 ascertain whether cane sugar was also present. 
 
 Lactose. 
 
 Lactose is a readily soluble and diffusible body, and, by virtue of 
 these properties, does not require to undergo change within the 
 alimentary canal to be rendered fit for absorption. I have subjected 
 lactose to the action of the coats of the stomach and intestine of the 
 rabbit, cat, and sheep, and have not obtained evidence of a decided 
 nature of any transformation being brought about. It is stated, 
 however, that, under the influence of inverting ferments, in the same 
 manner as by the action of acids, lactose is convertible into galactose 
 and dextrose, and that the succus entericus has the power of produc- 
 ing this eflect. Whether or not the transformation occurs physio- 
 logically, proof, it may be as.sumed, is afforded of the possibility of ils 
 occurrence within the system by the fact that in the diabetic ingested 
 lactose appeal's as glucose in the urine. 
 
 Lactose, as is well known, readily undergoes the lactic acid fer- 
 mentation in presence of certain micro-organisms. Apparently a 
 certain amount of tlie lactose reaching the alimentary canal becomes 
 transformed in this way. 
 
100 ingested caubohydltates tuaced to i'oktal blood. 
 
 Glucoses. 
 
 Glucose stands as the end product inside the carbohydrate series 
 of the action of ferments, &c., on the varions members of the group. 
 No change can therefore be looked for under exposure to the influ- 
 ence of the digeslive secretions, and none is required to be exerted, 
 seeing that, by virtue of its high solubility and diffusibility, it exists 
 in a fit state for passage into the circulation by absorption. After 
 ingestion, it can be traced into the portal blood. Like lactose, 
 though less readily, glucose is susceptible of undergoing the lactic 
 acid fermentation, and this change, under certain cii'cmristances, may, 
 to some extent, occur in the alimentary canal. 
 
101 
 
 PORTAL BLOOD IN RELATION TO INGESTED 
 CARBOHYDRATES. 
 
 I have traced the ingested carbohydrates on to the point at which 
 they stand as soluble diif usible bodies within the alimentary canal, in 
 close proximity to the vessels distributed upon its inner surface, and 
 thus in a favoui-able position for absorption into the circulation to 
 occur. I will now pass to the examination of the portal blood, and 
 see what evidence is adducible of their passage into it. 
 
 In entering upon this enquiry, it is necessary in the first place to 
 know the constitution of the portal blood, in relation to sugar, apart 
 from the influence of ingested carbohydrate matter. The blood of 
 the portal system contains a certain amount of sugar derived from 
 that existing as a constituent of the blood of the general circulation. 
 As I shall show in detail later on (p. 161), the blood of the general 
 circulation contains a standard or definite amount of sugar, which, 
 under natural and ordinary conditions, may be stated to range from 
 about 06 to 1"0, or a little orer 10, per 1000, and which presents no 
 evidence of any essential variation in the different parts of the 
 system spoken of. In considering, therefore, the question of the 
 effect produced upon the portal blood by the absorption of ingested 
 carbohydrate matter, the existence of this initial amount of sugar, 
 common to the blood as a whole, must be taken into account. 
 
 We start, then, with blood containing from about 0'6 to about 
 1"0 per 1000 of sugar, due to that belonging naturally to the general 
 circulation. 
 
 With this preliminary observation, I will proceed to give re.sults 
 showing the condition of the portal blood found : — 
 
 a. At a period of fasting. 
 
 h. After the ingestion of animal food. 
 
 c. After the ingestion of food rich in carbohydrate matter. 
 
 Some years ago I conducted an extensive series of experiments 
 upon the point under consideration, and the results showed a 
 marked increase of sugar after the ingestion of cai'bohvdrato 
 
102 INGESTED CAKBOHYDRATE IN PORTAL BLOOD. 
 
 material. Looking, however, at the importance of the matter from 
 the point of view of the conclusions that may be based upon it, I 
 have recently undertaken, in the Research Laboratories of the 
 Colleges of Physicians and Surgeons, a number of additional experi- 
 ments, which have been conducted with the advantage of the ana- 
 lytical experience gained from previous work. The results of these 
 experiments, it may be stated, exhibit a general conformity with 
 those formerly obtained. I will here give them in their entirety. 
 
 In each case the animal was suddenly killed by pithing. Instantly 
 afterwards, an incision was made through the abdominal parietes, and 
 the portal vein ligatured. The blood flowing to the liver was thus 
 caused to accumulate below the ligature, whilst at the same time any 
 backward flow from the organ was prevented. Blood was then 
 collected direct from the vessel. In some of the instances, it will 
 be noticed, two portions were collected and analysed. In these 
 cases the flow was for a few moments stopped, by compression of the 
 vessel, before the collection of the second portion. 
 
 It will be observed in the analytical results to follow that the kind 
 of sugar found in the portal blood is one possessing a cupric oxide 
 reducing power standing ordinarily below, and sometimes consider- 
 ably below, that of glucose. As will be seen from what will be stated 
 later on, a point of difierence here exists between the sugar of the 
 portal blood and that present in the general circulation, which, under 
 natural circumstances, is found to have the cupric oxide reducing 
 character of glucose. 
 
I'ORTAL BLOOD AFTER FASTING. 
 
 103 
 
 Portal Blood at a Period of Fasling. 
 
 per 1000, 
 expressed 
 as glueose. 
 
 Dog, neiirly 48 liours affe'- last food 
 
 Portal blood / '"''■'^'■^ sulplnirie aeid 
 
 0-580 
 0-643 
 
 • • ■ • 1 aft 
 
 Dog, nearly 48 hours after last food : 
 
 Portal blood .... I ^^/'"•« «"lpli""« ''"d O^f' 
 fatter „ „ 0-710 
 
 Babbit, fully 24 hours after last food : 
 
 Portal blood .... I ''f/"™ sulphuric aeid 1-583 
 (.after „ „ 1-733 
 
 Babbit, fully 24 hours after last food : 
 
 Portal blood .... I V'"'' '"^P^""" ""^' tf,t 
 Latter ,, ,, 2-499 
 
 Babbit, fully 24 hours after last food : 
 
 Portal blood . . . . ( ^f°'-' sulphurie aeid 2-244 
 [after „ „ 2-244 
 
 Eelation of the 
 
 cupric oxide 
 
 reducing power 
 
 of the sugar 
 
 present 
 
 to that of 
 
 glueose at 100. 
 
 1 PO 
 
 I 94 
 
 In tlie case of the two dogs (Experiments I and II), it will be 
 observed that the blood was collected after a fast of nearly 48 hours. 
 It may be concluded that influence from ingestion -would be here 
 absolutely excluded. The amount of sugar found stood within the 
 natural range given for the contents of the general circulation. The 
 prolonged fasting consequently, on its part, did not cause any 
 sensible diminution. 
 
 In the case of the rabbits (E.xperiments III, IV, and V), a difTerent 
 condition existed. Notwithstanding that fully twenty- four hours had 
 elapsed since the last food was taken, the blood gave evidence of 
 containing sugar derived from ingestion. In this animal, it is to be 
 remarked, the stomach is known to contain a considerable quantity 
 of material even after a much more prolonged period of fasting, and 
 doubtless the condition found is thus to be accounted for. Seeing 
 that the animal ordinarily will not be without food for twenty-four 
 hours, the circumstances, it will be perceived, are here such as to 
 lead to the portal blood containing as a constant condition more 
 sugar than that of the general circulatic,!!. 
 
104 
 
 IXGESTKD CARBOHYDKATE IN POKTAL DLOOD 
 
 Portal Blood, after Animal Food. 
 
 Sugar 
 per 1000, 
 expressed 
 
 as glucose. 
 I. Dog, fed for 3 days on lean beef ; killed 4 hours 
 after last food ; abundant chyme in intes- 
 tine : 
 
 Portal blood. 1st f before sulpliui'ie acid 1117 
 
 portion collected \ after ,, ,, l'3tO 
 
 Portal blood. 2nd / before sulphuric acid 1'335 
 
 portion collected \ after „ „ 1'031 
 
 11. 
 
 Dog, fed for 3 days on lean beef ; killed 4 hours 
 after last food ; no chyme visible in intestine : 
 
 Portal blood. 1st J before suljihuric acid 0'893 
 
 portion collected \ after ,, ,, 1'0S7 
 
 Portal blood. 2nd / before sulphuric acid 0'713 
 
 portion collected L after „ ,, 1'023 
 
 Dog, fed for 3 days on lean beef; killed 6i hoiu-s 
 after last food ; apparently in full diges- 
 tion : 
 
 '' before sulphuric acid OG33 
 ■[after „ „ 0083 
 
 Dog, fed for 2 days on lean beef ; killed h\ hours 
 after last food : 
 
 re sulphuric acid 0'593 
 0-660 
 
 Portal blood 
 
 Portal blood 
 
 J before 
 •■•• \ after 
 
 Portal blood 
 
 VII. 
 
 Dog, fed for 2 days on lean beef; killed 5i 
 hours after last food : 
 
 {before sulphuric acid 0'633 
 after „ „ 0707 
 
 Dog, fed on lean beef ; killed 5 hours after last 
 food : 
 
 Portal blood. 1st J before sulphuric acid 0750 
 
 portion collected \ after „ „ 77t> 
 
 Portal blood. 2nd / before sulphuric acid 0'693 
 
 portion collected \ after ,, ,, 0'817 
 
 Dog, fed on lean beef; killed 5^ hours after 
 last food : 
 
 Portal blood .... 1^^!"'' ^"Iph""'' i"d 0720 
 (.alter „ „ 0720 
 
 Cat, fed on meat ; 
 food : 
 
 Portal blood . 
 
 killed 5 hours after last 
 
 r before sulphuric acid 0'851 
 •• t after „ „ 1139 
 
 Cat, fed on meat; killed 5 hours after last 
 food : 
 
 p ,. , . J ] f before sulphuric acid 0675 
 
 Eelation of the 
 
 cupric oxide 
 
 reducing power 
 
 of the sugar 
 
 present 
 
 to that of 
 
 glucose at 100. 
 
rOETAL BLOOD AFTER STARCHY FOOD. 
 
 105 
 
 Portal Blood after the Ingestion of Starchy Food. 
 
 Eelation of the 
 
 eupric oxide 
 reducing power 
 Sugar of the sugar 
 
 per 1000, present 
 
 expressed to that of 
 
 a8 glucose, glucose at 100. 
 
 Dog, shortly after having been fed with a 
 little meat; 22 grams of starch in 200c.c. of 
 water injected into stomacli through an 
 oesophageal tube ; killed 30 minutes after- 
 wards : 
 
 f before sulphuric acid 1'210 
 {<' 
 
 Portal blood 
 
 after 
 
 1-207 
 
 Dog, fed on bread and milk ; killed 3i hours 
 afterwards : 
 
 Portal blood. 1st ("before sulphuric acid 1'1S3 
 
 portion collected \ after ,, ,, 1'477 
 
 Portal blood. 2nd J before sulphuric acid 1'7G3 
 
 portion collected | after „ ,, 2500 
 
 III. Dog, fed on bread and milk ; fed badly ; killed 
 
 4 hours afterwards : 
 
 {before sulphuric acid l']53 
 after „ „ 1-270 
 
 Dog, fed on bread and broth ; killed 2 hours 
 afterwards : 
 
 J before sulphuric acid 0-977 
 1 after „ „ 1100 
 
 v. Dog, fed on bread and broth ; killed about 1 
 hour af terwartls ; 
 
 f before sulphm'ic acid 0-9C8 
 [after „ „ 1-277 
 
 Dog, fed on bread and broth ; killed 2 hours 
 afterwards : 
 
 r before sulphuric acid 1-723 
 Latter „ „ 2187 
 
 Dog, fed on bread, milk, and meat; killed 2i 
 hours afterwards : 
 
 f before sulphuric acid 1'403 
 ' ■* t after „ „ 1930 
 
 VIII. Rabbit, fed on moistened oats ; killed 2 hours 
 afterwards : 
 
 f before sulphuric acid 2-587 
 [after „ ,, 3-234 
 
 Rabbit, fed on moistened oats and green food ; 
 killed 3 hours afterwards : 
 
 J before sulphuric acid 2-346 
 •••• 1 after „ „ 2-878 
 
 Rabbit, fed on moistened oats ; killed 4 hours 
 afterwards : 
 
 {before sulphuric acid 1-630 
 after „ „ 2 085 
 
 IV. 
 
 VI. 
 
 VII. 
 
 IX. 
 
 Portal blood 
 
 Poital blood 
 
 Portal blood 
 
 Portal blood 
 
 Portal blood 
 
 Portal blood 
 
 Portal blood 
 
 Portal blood 
 
 96 
 
106 
 
 INGESTED CARBOHYDRATE IN POltTAL P.I.OOD. 
 
 Portal Blood after Ingestion of Starchy Food (continued) 
 
 Relation of the 
 
 cupric oxide 
 reducing power 
 Sugar of the sugar 
 
 per 1000, present 
 
 expressed to that of 
 
 as glucose, glucose at 100. 
 Rabbit, fed on moistened oats; liilled 4 hours 
 afterwards : 
 
 f before sulphuric acid 2'109 \ ,„ 
 
 [after „ „ 2-903 J ' 
 
 Rabbit, fed on moistened oats j killed 4 hours 
 afterwards : 
 
 f before sulphuric acid 1'431 
 [after „ „ 1-816 
 
 Xlll. Babbit, fed on moistened oatsj killed 4i to 5 
 hours afterwards : 
 
 XII. 
 
 Portal blood 
 
 Portal blood . . 
 
 p . , , , , J before sulphuric acid 3-665 
 
 ■■ ■ ■ [alter ,, „ 4-102 
 
 XIV. 
 
 Babbit, fed on moistened oats ; killed 4i to 5 
 hours afterwards : 
 
 before sulphuric acid 4-1590 
 after „ „ 5330 
 
 Portal blood 
 
 Babbit, fed on moistened outs ; killed 4} to 5 
 hours afterwards ; 
 
 Portal blood . . . . { ^f,^''' «"ll>l"Tie acid 4 070 
 Latter „ ,, 40SI0 
 
 Babbit, fed on moistened oats; killed 5 to 5i 
 hours afterwards ; 
 
 r before sulphuric acid 1-J(il 
 [after „ ,, l'G57 
 
 Portal blood 
 
 XVII. 
 
 Babbit, fed on tnoistened oats ; killed 5 to 5.i 
 hours afterwards i 
 
 {before sulphuric acid 1'142 
 after „ „ 1-615 
 
 Portal blood 
 
 XVIII. Babbit, fed on moistened oats; killed 5 to 5i 
 hours afterwards ; 
 
 Tj , 1 , 1 J f before sulphuric acid 1413 
 
 Portal blood .... I ^fj^^ '„ „ 1-567 
 
 XIX. 
 
 XX. 
 
 Rabbit, fed on moistened oats; killed 5 to 5i 
 hours afterwards : 
 
 Portal blood 
 
 ....{ 
 
 before sulphuric acid 1-693 
 after „ „ 1698 
 
 Babbit, fed on moistened oats ; killed shortly 
 after being fed : 
 
 Portal blood - - -T ''"'■°'"'' ^"Ipl"'"'' "'■"I ^■■^l 
 
 \ after 
 
 } ^» 
 
 89 
 
 1-707 
 
I'ORTAL BLOOD AFTER MALTOSE. 
 
 107 
 
 Osazone from the sugar of the portal blood of rabbits at a period of digestion. 
 Magnified 400 diameters. 
 
 Portal Blood after the Ingestion of Maltose. 
 
 Sugar 
 per 1000, 
 expressed 
 fts glucose. 
 I. Dog, 24 hours after last foocl ; 32 grame of 
 maltose in 85 c.c. of water injected into 
 stomach through an oesophageal tube j 
 killed 25 minutes afterwards : 
 
 Portal blood 
 
 J before sulphuric iicid 
 1 after ., 
 
 1-600 
 2-200 
 
 Relation of the 
 
 cupric oxide 
 
 reducing power 
 
 of the sugar 
 
 present 
 
 to that of 
 
 glucose at 100, 
 
108 IXGESTED CAKBOHYDIIATE IN POIITAL BLOOD. 
 
 Portal Blood after the Ingestion of Cane Sugar. 
 To ascertain if cane sugar passes as such into the portal blood, it is 
 necessary to resort in tbe process of analysis to the employment of 
 citric acid instead of sulphuric acid. Alcoholic extraction is under- 
 taken in the usual way, but at the end of the evaporation sulphate of 
 soda must not be used, as the presence of this agent, it is found, 
 more or less interferes with the inverting action of organic acids 
 upon cane sugar. A less satisfactory product is given for titration, 
 but this is unavoidable. After filtration, preferably through glass 
 wool, has been performed, the liquid is brought to a given bulk and 
 divided into two portions. One portion is titi-ated at once, whilst 
 the other is boiled for seven minutes with 2 per cent, citric acid, 
 neutralised, and then titi-ated. Any increase revealed by the second 
 
 titration is representative of cane sugar. 
 
 Sugar 
 per 1000, 
 expressed 
 as glucose. 
 I, Dog, shortly after having been fed with a little 
 meat ; 33 grams of cane sugar in 200 c.c. of 
 water injected into stomach through an 
 oesophageal tube ; killed 30 minutes after- 
 wards : 
 
 Portal blood. 1st /before citric acid. . .. 1-333 
 
 portion collected \ after 1'333 
 
 Portal blood. 2nd / before citric acid. . . . 1'520 
 portion collected \ after „ .... 1'522 
 
 II. Dog, not fed since previous day ; 70 grams of 
 cane sugar in 210 c.c. of water injected into 
 stomach ; killed 30 minutes afterwards : 
 
 T, . 1 , , , r before citric acid. ,. . 2"113 
 
 Portal blood .... I ^^.^^^ „ .... 2-113 
 
 III. Dog, not fed since previous day ; 70 grams of 
 cane sugar in 210 c.c. of water injected into 
 stomach ; killed 30 minutes afterwards : 
 
 T, , , v, J r before citric acid ... . 1-844 
 Portal blood .... I ^j.^^^ , 1-600 
 
 It will bo noticed in the first two observations that the figures 
 yielded before and after citric acid stand in strikingly close accord. 
 In the third a disparity exists which can only arise from error of 
 analysis, seeing that the figures after citric acid are lower than those 
 before. The inference from these results is that carbohydrate derived 
 from the ingested cane sugar reached the portal blood as glucose and 
 not in the state of cane sugar. 
 
109 
 
 THE LIVER, IN- RELATION TO THE SUGAR DERIVED 
 FROM INGESTED CARBOHYDRATES. 
 
 From the results which have preceded, evidence is afforded that 
 ingested carbohydi'ate matter passes in the form of sugar from the 
 alimentary tract into the blood of the portal system. By the portal 
 system the sugar is conveyed to the liver, and the next point for con- 
 sideration is the question of what now becomes of it. Does it pass 
 through the organ and reach the general circulation, or is it stopped 
 and disposed of in some other manner ? 
 
 The examination of this question may be approached from two 
 Bides : from the one, by comparing the condition of the blood taken 
 before and after passing through the liver ; and, from the other, by 
 looking to the condition of the liver itself, in relation to the influence 
 exerted by the ingestion of carbohydrate food. Let us see what 
 light is thrown on the matter by appeal to experimental investiga- 
 tion, looking first at the information derivable from an examination 
 of the blood. 
 
 1. Evidence afforded hi/ the Blood of Sugar being stopped hy the Liver. 
 
 Seeing, as has been shown in the preceding pages, that the blood 
 of the portal system after the ingestion of carbohydrate matter con- 
 tains more sugar than that of otiier pai-ts of the circulation, we have 
 a fact to deal with which points in two directions. It implies not 
 only entry of sugar by absorption through the capillary radicles of the 
 portal system in the walls of the alimentary canal, but also exit by 
 abstraction on reaching the terminal capillaries in the liver. 
 
 It is the latter point, namely, the abstraction of sugar from the 
 poital blood by the liver, that we have now to consider, and its con- 
 sideration requires that attention should be given to the condition of 
 the blood flowing from, as compared with that flowing to, the organ. 
 
 The portal vein, after entering the liver, terminates in capillaries, 
 from which the hepatic vein takes origin and passes to empty itself 
 
110 LlVEIt IS KELATION TO INGKSTED CAKBOIIYDUATE. 
 
 into the inferior cava. The blood, therefore, to be compared is that 
 contained, on the one hand, in the portal, and, on the other, in the 
 hepatic vein. The collection of blood in a suitable state for examina- 
 tion from the former is easily made. It is also within the range of 
 possibility to make the collection from the latter. It can be done 
 during life by passing a properly constructed catheter down through 
 the right jugular, the superior cava, the right auricle of the heart, 
 and the inferior cava, to the seat of entrance of the hepatic veins. 
 The operation, however, like other operations on the living animal 
 attended with a disturbance of the tranquil and natural state, con- 
 duces to the production of an altered condition of the blood in rela- 
 tion to sugar, and cannot be relied upon to yield the desired informa- 
 tion, which must therefore be sought for in some other way. 
 
 How speidily an alteration in the state of the blood, attended 
 with the presence of an abnormal amount of sugar, may take place 
 through the influence of altered conditions connected with the liver, 
 I illustrated at the outset of my researches, now upwards of thirty 
 years ago. From the readiness with which the blood flowing from 
 the liver is thus thrown into an altered state, it is necessary that 
 close attention should be given, and proper precautions observed, to 
 escape being misled ; otherwise, sugar may be met with more or 
 less greatly in excess of what is ordinarily present, and the inference 
 thence be erroneously drawn that its discharge from the liver takes 
 place in a manner that does not naturally occur. 
 
 In dealing with the problem before us, it is, then, a matter of 
 primary importance that the blood taken for examination should be 
 in a state representative of that naturally belonging to life. To 
 obtain such a specimen directly from the hepatic veins is, I consider, 
 a procedure attended with so much liability to the introduction of 
 error as to be unsuited for employment. With the blood of the right 
 side of the heart, however, in which that flowing from the liver is 
 present, mixed with that derived from the systemic veins, no such 
 difiBculty exists. This is easily obtained in a state representative of 
 that naturally belonging to life, and, through its examination, in- 
 formation may be indirectly obtained regarding the constitution of 
 the hepatic blood of which it in part consists. Later on (vide p. 164), 
 I shall enter into details about the operative procedure to be adopted. 
 SuflBce it here to state that I consider tlie bist method is to make the 
 
SUGAR OF POKTAL AND SYSTEMIC BLOOD. Ill 
 
 collection instantly after the sudden destruction of life. With the 
 observance of quickness throughout, the blood may thus be obtained 
 befoi-e time has been given for any change of condition to occiu-. 
 
 The amount of sugar found in the blood collected from the heart 
 in the manner just described ranges, as I have previously stated, 
 from about 06 to 1"0, or a little over 1"0, per 1000 — the amount 
 agreeing with that met with in the blood of the systemic veins as it 
 is circulating under natural conditions. If an influx of sugar took 
 place through the hepatic veins, the effect should be visible in the 
 cardiac, on being compared with the general systemic venous, blood ; 
 but observation does not show that any recognisable difference exists 
 between the two. 
 
 I may mention that it has sometimes happened, in my experiments 
 for collecting blood for examination from the right side of the heart, 
 that, in the haste of manipulation, the scissors have been plunged 
 into the chest in too much of a downward direction, and that the 
 diaphragm and contiguous portions of the liver adjoining the inferior 
 cava have been incised, without the heart being touched. Under 
 these circumstances, the blood which escaped was derived, in con- 
 siderable amount, directly from the divided hepatic veins, but the 
 analytical results subsequently obtained showed no perceptible differ- 
 ence from those yielded by the blood procured from the heart. 
 
 The position, then, of the matter actiially before us for considera- 
 tion stands thus : — -The portal blood, after the ingestion of carbo- 
 hydrate matter, contains sugar amounting to from about 1'6 to 2, 3,4, 
 or even more per 1000, whilst the blood on the other side of the liver, 
 under similar circumstances, does not afford evidence of containing 
 more than from about 06 to I'O, or a little over 1"0, per 1000. The 
 conclusion to be drawn is that the surplus amount of sugar found in 
 the portal blood is abstracted from it during its passage through the 
 vessels of the liver. 
 
 It will be noticed that what I have asserted is in direct opposition 
 to the tenets of the glycogenic theory propounded by Bernard. The 
 discrepancy, as shown elsewhere in this work, is attributable to a 
 want of recognition of the fact that the amount of sugar found in 
 the blood on the cardiac side of the liver, in the absence of the pre- 
 cautions requiring to be observed in procuring it for examination, is 
 largely' in excess of what is natural. 
 
112 LIVER IN KELATION TO INGESTED CARBOIIYDKATE. 
 
 The office performed by the liver, of abstracting sugar from the 
 portal blood, has the effect of maintaining the contents of the general 
 circulation in a state of uniformity. If the sugar derived from 
 ingested carbohydrate matter were allowed to pass through the liver 
 and reach the general circulation, a disturbance of this uniformity 
 "would be constantly occurring. Such a state of things, indeed, is 
 precisely what exists in diabetes. Whilst, in health, the blood of 
 the general circulation is shielded from variations due to the influence 
 of ingested carbohydi-ate matter, and the urine remains impregnated 
 (vide p. 186) with only an insignificant amount of sugar, correspond- 
 ing with the small amount existing naturally in the blood : in 
 diabetes, sugar reaches the general circulation, and thence the urine, 
 in proportion as carbohydrate matter enters the portal system from 
 ingestion. The blood of the portal system, in the natural order of 
 things, is variable in character, from the influence exerted by inges- 
 tion ; and should it happen that such variability of character is allowed 
 to be transmitted to the blood on the other side of the liver, the result 
 occurring is a proportionate escape of sugar with the urine — in othex" 
 words, the production of the condition belonging to diabetes. 
 
 2. Evidence afforded through the Liver itself of the Stoppage hy it of 
 Sugar derived from Ingestion. 
 
 Having dealt with the question under consideration from the point 
 of view of the comparative condition of the blood on the two sides of 
 the liver, we have next to look to the state jf the liver itself to see if 
 evidence is obtainable of the detention of the carbohydrate matter 
 conveyed to it by the blood from the alimentary tract. 
 
 In entering upon the examination of this question, I am carried 
 back to investigations conducted almost at the commencement of my 
 association with physiological research, some thirty-five years ago. The 
 announcement had been made by Claude Bernard, in 1848, that the 
 liver possessed a sugar-forming function. Bernard had set before 
 himself the task of ascertaining what became, within the system, of 
 the sugar derived from ingested carbohydrate matter. In the prose- 
 cution of his inquiry, he conducted observations upon animals which 
 had been kept on food of a saccharine nature, and was led to conclude 
 that he had traced the sugar through the liver into the general circula- 
 
Bernard's discovery of glycogen 113 
 
 tion as far as the right side of the heart. In order to prove that the 
 sugar here met with had been derived from the food, he performed a 
 counterpart experiment upon an animal -which had been kept upon 
 meat only, and, contrary to expectation, still found sugar in the 
 contents of the circulatory system, in the same manner as before. 
 Here arose the starting point for his glycogenic theory. At first, as 
 a part of the theory, he regarded the production of sugar as due to a 
 vital process of the nature of secretion, looking upon albuminoid 
 matter as contributing to its formation. Subsequently, however, he 
 discovered the body from which the sugar actually takes oiigin, and, 
 from the physiological position which ho regarded it as holding, he 
 gave it the name of glycogen. In the course of his investigations, he 
 found that this material underwent transformation into sugai', not 
 only after removal of the liver from the animal, but even after the 
 passage of a stream of water through the vessels, to thoroughly wash 
 out the blood. He further extracted and isolated the newly dis- 
 covered body, and found that it consisted of a carbohydrate. The 
 announcement of its isolation was made in the year 1857. 
 
 Up to this time, our knowledge had not been brought into a more 
 advanced position than this. But the new line of research which 
 was opened out excited a great amount of interest in the scientific 
 world, and drew various workers into the field of enquiry. I stood 
 as one of these, and, at the same time, as one who had been an eye- 
 witness of Bernard's experimental work ; and, in the prosecution of 
 the researches I oonducted, I found that the principle which had 
 been recognised as the source of sugar in the liver was itself derived 
 from ingested carbohydrate matter. This discovery was made in the 
 year 1858, and the particulars relating to the subject were given in a 
 communication published in the 'Phil. Trans.' for 1860 (p. 579). I 
 will here introduce an epitomised representation of the points of 
 evidence brought forward in the communication referred to. 
 
 I will dii-ect attention first to the observations conducted upon 
 dogs, and in these observations it will be understood that all the 
 animals were in good condition, and in no way specially selected. In 
 each case, the dog was fed for some days npon the particular food the 
 influence of which upon the liver it was desired to examine, and was 
 then killed by pithing, after being weighed. The liver was at once 
 removed and weighed, without the gall bladder and after the blood 
 
114 LIVKU IN DELATION TO INGESTED CARBOHYDKATE. 
 
 had been allowed to drain off. In most instances a determination 
 was also made of the amount of glycogen present. The process cm- 
 ployed for the determination of glycogen had not, it should be stated, 
 then attained the satisfactory position of that now at our disposal, in 
 which the estimation is effected by converting into glucose and deter- 
 mining the amount of this principle by means of the ammoniated cupiio 
 test. At that time the plan adopted was simply to boil the liver with 
 potash and then to precipitate the glycogen by pouring into spirit. 
 This precipitate was weighed and reckoned as glycogen, and, although 
 not consisting purely of glycogen, it gave a fair I'epi-esentation of the 
 relative amount existing in different livers. 
 
 To serve as a basis of comparison, eleven dogs were killed after 
 being restricted to a diet of purely animal food. In these instances 
 the average relation of liver- weight to body- weight "was as 1 to 30. 
 The actual figures ranged from I to 33, as the lowest, to 1 to 21, as 
 the highest, the latter instance standing alone in giving so high a 
 relative weight of liver. A determination was made of the per- 
 centage of crude glycogen precipitate yielded by seven of the livers, 
 and the figures obtained ranged from 488 to 10'95, averaging 7"19. 
 
 To obtain information as to the effect upon the liver of a diet of 
 vegetable food with its preponderance of carbohydrate material, five 
 dogs were fed for several days on barley-meal and potatoes, or, when 
 fhis was refused, on bread and potatoes. The average weight of the 
 liver was here found to be one-fifteenth of the body-weight, the 
 figures expressing the actual ratios standing thus : — 
 
 1 to 14-5 
 
 1 „ 14-5 
 
 I „ 210 
 
 1 „ 10-5 
 
 1 „ 22-5 
 
 No analyses were made of the livers of the first two of these dogs, 
 but the qjautity of glycogen, as evidenced by the sti-ongly milky 
 character of the decoctions yielded, was unusually large. In fact, it 
 was whilst examining these livers in relation to the question of sugar 
 that I was first led to notice the effect of vegetable food, to which I 
 am now referring. The liver of the third dog was not examined 
 until an hour and a half after death. The crude glycogen precipitate 
 
GLYCOGEN FROM CARBOHYDRATE FOOD. 115 
 
 then yielded amounted to 987 per cent. In the fourth instance the 
 liver gave 25'30 per cent, of crvide glycogen precipitate, and in the 
 fifth 16'50 per cent. The average percentage of crude glycogen pre- 
 cipitate for the three livers was therefore 17"23, a result standing in 
 marked contrast to the amount obtained after animal food. 
 
 In another set of observations sugar was given in conjunction with 
 animal food. The sugar employed consisted of cane sugar — the 
 brown or moist sugar in common use. Four dogs were subjected to 
 this regimen. 
 
 1. A nearly full-grown dog was kept for eight days on a diet con- 
 sisting of a bundle of tripe, with at first j lb. and afterwards ^ lb. of 
 sugar per diem. The liver-weight was found to stand to the body- 
 weight as 1 to 13 5, and the liver yielded 128 per cent, of crude 
 glycogen precipitate. 
 
 2. A young dog was fed for nine days on a bundle of tripe and ^ lb. 
 of sugar daily. The ratio between liver- and body-weight stood as 1 
 to 145, the liver yielding 17"55 per cent, of crude glycogen pre- 
 cipitate. 
 
 3. A full-grown dog was kept for eight days on a daily allowance 
 of a bundle of tripe and ^ lb. of sugar. The weight of the liver stood 
 to the weight of the body as 1 to 26. The percentage of crude glyco- 
 gen precipitate yielded was 12"33. 
 
 4. A nearly full-grown dog was fed for five days on a diet similar 
 to that last mentioned. Here the liver-weight was one-fourteenth of 
 the body-weight, a^id the percentage of crude glycogen precipitate 
 15-37. 
 
 The four examples here given present, as the average of liver-weight 
 to body-weight, the ratio 1 to 15, and an average of 14'5 as the per- 
 centage of crude glycogen precipitate yielded by the liver : i-esults 
 pretty closely corresponding in character with those observed after 
 a diet of ordinaiy vegetable food. 
 
 In both of these last sets of results it is noticeable that the liver 
 is markedly increased in size and weight as compared with what is 
 found to obtain after a diet of animal food, and this increase stands 
 in harmony with the large proportion of crude glycogen precipitate 
 yielded. 
 
 With reference to the observations on the effect of an admixture of 
 sugar with animal food, it may be incidentally mentioned that (he 
 
 I 2 
 
116 LIVER -IN RELATION TO INGESTED CAKBOHYDKATE. 
 
 liver was found to present an appearance strikingly different from 
 what is usual. After purely animal food it is comparatively dark 
 coloured, and of so firm and fleshy a consistence as to require consider- 
 able pressure to break it down between the fingers. After the ad- 
 ministration of sugar, however, the liver was found to be pale coloured, 
 with a tinge of pink, and soft enough in consistence to be readily 
 broken down by a very slight pressure. It had the appearance of 
 being swollen and flabby. 
 
 Another point that is worthy of being mentioned is that in three 
 out of the four instances where sugar was administered, the urine 
 collected from the bladder after death was found to contain sugar in 
 the form of glucose, although cane sugar had been administered. 
 
 Proceeding now to the experiments on the rabbit, we find that the 
 evidence yielded is such as to show in a simple and conclusive manner 
 that ingested carbohydrates lead to the formation of glycogen in the 
 liver. 
 
 1. A couple of full-grown rabbits, as Closely as possible resembling 
 each other in weight and condition, were taken for expei'iment. One 
 was kept fasting', whilst the other was fed daily for three days, through 
 a flexible tube passed down the cesophagus to the stomach, with 1 oz 
 of starch and ^ oz. of grape sugar, made into a semi-fluid mass with 
 water. On the fourth day both animals were killed. The weight of 
 the fasting animal was 3 lbs. 1 oz., that of the other 3 lbs. 4 ozs. The 
 liver of the fasting animal weighed If ozs., that of the other 2* ozs., 
 or exactly twice as much. 
 
 The liver of the rabbit fed on starch and grape sugar was rich in 
 glycogen, yielding 1.5'4 per cent, of crude precipitate, whilst that of 
 the other rabbit only yielded I'S per cent. 
 
 In another experiment two half-grown rabbits, likewise as nearly 
 as possible resembling each other, were made the subjects of a com- 
 parative observation. One was kept fasting, whilst the other was fed 
 daily for three days in the same manner as before, with 1 oz. of starch 
 and I oz. of cane sugar instead of grape sugar as in the former ob- 
 servation. On the fourth day both animals were killed, and the 
 examination conducted. The weight of the fasting animal was 1 lb. 
 14 ozs., and that of the other 1 lb. 14| oz. The liver of the fasting 
 rabbit weighed 1 oz., and that of the other 2f ozs., or considerably 
 moi'e than twice as much. The liver of the rabbit fed on starch 
 
TRAXSJrUTATION OF SUGAR INTO GLYCOGEN. 117 
 
 and cane sugiir yielded 169 per cent, of crude glycogen precipitate, 
 whilst the liver of the other yielded only 1'4 per cent. 
 
 A.S in the ca.se of the dogs after the administration of sugar with 
 animal food, the livers of the rabbits fed on starch and sugar were of 
 a very pale colour, and so soft as to be leadily broken down by slight 
 pressure between the fingers. This, as I have already remarked, is 
 the condition presented by the liver when rich in glycogen. In an 
 instance of unusual richness that happened to fall under my observa- 
 tion, the liver was, indeed, so soft as to be almost pulpy, scarcely 
 holding together when taken up by a pair of forceps. 
 
 The result of experience since these observations were made is to 
 confirm the conclusion that was drawn from them — namely, that the 
 ingestion of carbohydrate matter leads to the presence of an increased 
 amount of glycogen in the liver. This, indeed, may now be legarded 
 as an accepted physiological fact, and it is turned to account in the 
 practice which is resorted to of feeding an animal largely with carbo- 
 hydrate matter previously to its being killed, when it is desired to 
 obtain glycogen in quantity from the liver. 
 
 Looking, then, to the information derivable alike from the blood 
 and from the liver, we find evidence is afforded that the sugar 
 emanating from ingested carbohydrate matter is carried to the liver 
 by the portal blood and there checked in its progress, instead of being 
 allowed to pass on and reach the general cii'cvilation. It is through 
 the agency of the hepatic cells that this effect is produced, and within 
 them a concurrent accumulation of glycogen has been observed by 
 micro- chemical examination to take place. Thus the diffusible carbo- 
 hydrate which has reached the portal blood becomes abstracted and 
 transmuted by the hepatic cells into the non-diffusible form of it — 
 glycogen. The process of transmutation that here occurs constitutes 
 an instance of the carrying down of carbohydrate matter to a lower 
 state of hydration, an operation of the reverse nature of that Avhich 
 is noticed to be brought about by agencies acting apart from the in- 
 fluence of living matter. The transformations effected in the labora- 
 tory by ferment action and chemical agents are, as is known, trans- 
 formations attended with increased hydration. 
 
118 LIVER IN RELATION TO INGESTED CARBOHYDRATE. 
 
 Animal Food as a Source of Qhjcogeu. 
 
 The issue of what has preceded is that ingested carbohydrate 
 matter can be traced from tlie alimentary canal through the portal 
 system to the liver, where it becomes stopped in its progress, and 
 transformed from the state of sugar into that of glycogen, with the 
 result that the amount of the latter present in the organ fluctuates 
 according to the amount of carbohydrate matter ingested. 
 
 It is known, however, that glycogen is discoverable in the liver 
 apart from the ingestion of saccharine and starchy articles of food. 
 Under a diet of purely animal food, glycogen, to a certain extent, is 
 found to exist, and its origin has been referred to a breaking up of 
 nitrogenous matter within the liver itself. Another explanation, 
 however, which carries us back to what takes place antecedent to 
 absorption and stands in harmony with the general train of 
 events occurring in connexion with digestion, is susceptible of being 
 given. 
 
 In the first place, it maybe said that animal food contains a certain 
 amount of sugar. Probably the statement is within the limits of 
 truth that no living substance exists which does not contain proteid, 
 carbohydrate, fatty, and mineral matter, and, in accord with this pro- 
 position, flesh and other animal substances consumed as food can be 
 shown by analysis to contain free carbohydrate under the form of 
 sugar, and, to some extent also, of glycogen. Sugar from these 
 sources will, as a result of the ordinary operations of alimentation, 
 reach the portal vein and thence the liver. 
 
 Ordinary beef tea may be selected to illustrate the point in 
 question, and subjoined is a photo-engraving of a micro-photograph 
 fo the osazone derived (lom the sugar present. 
 
GLYCOGEN FROM ANIMAL FOOD. 119 
 
 Osazone from tlie sugar present in ordinary beef tea. 
 Magnified 400 diameters. 
 
 In the next place, besides the free carbohydrate existing as a con- 
 stituent of animal substances, there exists, as I have shown in what 
 I have said when speaking of the glucoside constitution of proteid 
 matter, carbohydrate in a locked up state. Not only is this carbo- 
 hydrate susceptible of being liberated by the cleaving agency of acids 
 and alkalis, but likewise by that of ferment action, it having, as a 
 matter of fact, been experimentally shown (p. 50) to be set free by 
 ordinary pepsin digestion. For the recognition, however, of the 
 liberated carbohydrate material, the copper test is Hot satisfactorily 
 available, on account of the masking effect of the peptone concur- 
 rently produced. With the phenylhydrazine test, it happens that 
 the peptone does not similarly constitute a source of difEculty, 
 osazone crystals being obtainable in its presence. Subjoined is a 
 representation of osazone crystals derived from a purchased sample 
 of peptonised meat.* 
 
 * " Fluid meat " prepared by Savory and Moore. 
 
120 LIVER IN HELATION TO INGESTED CARBOIIVDIiATE. 
 
 Osazoiie from the sugar present in peptonised meat. 
 Magnified 400 diameters. 
 
 In animal food, then, we have a certain amount of free carbohydrate 
 under the forms of both sugar and glycogen, and likewise a source of 
 carbohydrate in the cleavage action of digestion upon proteid matter. 
 As with vegetable food, in fact, carbohydrate is supplied, though to a 
 less extent, for alimentation ; and, in harmony with this, the results 
 given by examination of the portal blood may be taken, I consider, 
 as affording evidence of the occurrence of carbohydrate absorption. 
 If reference be made to the collection of results that have been given 
 of the examination of portal blood after animal food, it is noticeable 
 that, whilst in several instances no positive evidence, it is true, is 
 perceptible of augmentation of sugar from absorption, yet in others 
 
GLYCOGEN FROM ANIMAL FOOD. 121 
 
 there are indications pointing to its existence. Moreover, in some of 
 tho instances in which first and second portions of blood were col- 
 lected, the latter showed the presence of a larger quantity of sugar, 
 suggesting that with the longer detention in the capillary vessels a 
 greater absorption occurred. It must be remembered that with the 
 ligature of the portal vein the flow of blood through the liver is 
 checked, and that the contents of the circulation are thereby pre- 
 vented from being influenced in the manner that ordinarily occurs 
 as the effect of sugar production after death. 
 
 There is evidence, as will elsewhere in this work be shown, suggest- 
 ing that a certain amount of carbohydrate is applied to the formation 
 of proteid and fat by the agency of the protoplasmic chemical power 
 possessed by the cells of the intestinal villi ; and it follows that, in pro- 
 portion as the carbohydrate absorbed from the contents of the alimen- 
 tary canal is thus diverted, less will b3 left for passage in the free 
 state into the portal blood. In this way it may happen that the 
 evidence of absorption afforded by the portal blood is less certain and 
 pronounced than it otherwise would be. 
 
 From the foregoing considerations it is seen that a source for the 
 glycogen of the liver exists in animal alimentation in every way com- 
 parable to that existing in connexion with vegetable alimentation. 
 The only difference is one of degree in the amount of carbohydrate- 
 supply, and this harmonises with the difference in the respective 
 amounts of glycogen found to be present in the liver under the two 
 kinds of alimentation. 
 
 Authorities speak of glycogen taking origin from proteid matter 
 within the liver by a proteolytic action exerted by its cells. It has 
 been in this way considered that the presence of glycogen is to be 
 accounted for under subsistence upon animal food. I have shown, 
 however, that another explanation can be given, without looking to 
 the liver for the performance of a proteolytic office. The source of 
 the glycogen is sufficiently to be accounted for by the occurrence of 
 the same kind of action as that which is in operation after the inges- 
 tion of vegetable carbohydrate food. It is the province of ferment 
 action to break up and hydrate, and of protoplasmic action to syn- 
 thesise and de-hydrate. The proposition, therefore, which I have 
 advanced stands in accord with the natural order of events, whilst to 
 assume that the protoplasmic liver-cells perform the work of ferment 
 
122 LIVER IN RELATION TO INGESTED CARBOHYDRATE. 
 
 action does not. That tliey slionkl do-liydrate or transmute sugar into 
 glycogen is, on the other hand, consistent witli what can be shown to 
 be accomplished by protoplasmic matter elsewhere. 
 
 General Belations of Glyrngen as a Constituent, of the Lvver. 
 
 I have hitherto been speaking of the glycogen of the liver in relation 
 to its origin from ingested carbohydrate and proteid substances. 1 
 have now to direct attention to its general relations as a constituent 
 of the liver. 
 
 Glycogen is recognisable in the liver-cells by micro-chemical 
 examination, and is represented as existing in a hyaline state, together 
 with fat globules and pi-oteid granules, in the meshes of the proto- 
 plasmic network of the cell. As the result of treatment with iodine, 
 the glycogen is brought into view by the red-brown staining that 
 occurs. It may be dissolved out by water, leaving the network of the 
 cell-protoplasm intact. In spite of its ready solubility, its extrac- 
 tion by water from the liver-substance is not, however, easily to be 
 effected, owing, it may be assumed, to its non-diffusible nature. 
 
 It is known that even a diffusible body like glucose requires sedulous 
 treatment with water for its complete extraction from the (issues. 
 With glycogen, the difficulty is very much greater, and even after the 
 liver has been brought into a state of comparatively fine subdivision 
 by pounding in a mortar, and has been subjected to successive boil- 
 ings with water until no signs of further extraction are afforded, a 
 considerable quantity remains unremoved. If, afterwards, the residue 
 be set aside in a little water until the following day, the liquid will 
 be found to have become again milky in appearance from the further 
 extraction that has ensued. The .same occurrence niay be noticeable 
 oven with several successive daily repetitions of the treatment, and 
 finally the residue on examination may still be found to contain a con- 
 siderable quantity of glycogen. I drew attention to this circumstance 
 in a communication pi'esented to the Royal Society in 1881 ; and 
 from the detailed observations therein narrated I will select one for 
 the purpose of illustration. 
 
 A weighed quantity of the liver of a recently killed dog was 
 reduced to a pulp in a mortar and thoroughly extracted with alcohol 
 for the removal of its sugar. The coagulated residue from the 
 alcoholic washings was then repeatedly extracted with boiling water 
 
GENERAL liELATIOXS OF GLYCOGEN IX LIVEK. 123 
 
 till the liquid came away clear, instead of lactescent, from tlie presence 
 of glycogen, as at first. The residue was kept ia a moist state till the 
 following day, when the process of washing was repeated. On the 
 third and fourth days the process was again repeated until in each 
 case a clear liquid was obtained. The glycogen in each day's wash- 
 ings was estimated by conversion into glucose and recourse to titra- 
 tion with the amnioniated cupric test. Finally, the residue from the 
 successive washings was boiled with potash and poured into spirit for 
 the collection and estimation of the glycog-en remaining. The figures 
 yielded stood as follows : — 
 
 Per 1000 of lirer. 
 
 Glycogen extracted on the 1st day 138ri3 
 
 2nd „ 3-870 
 
 3rd „ 2-961 
 
 4th „ 2-817 
 
 ,, remaining in the residue 35-145 
 
 It will thus be seen that the repeated extractions on the four suc- 
 cessive days removed only something under half of the total amount 
 of glycogen contained in the liver. The above results, together 
 with others from similarly conducted observations, show how imper- 
 fectly ordinary extraction with water removes glycogen from the 
 liver-substance, and account for the small quantity, compared with 
 what might be expected, that is not unfrequently obtained when 
 the process of collection by aqueous extraction is adopted. 
 
 The extent to which glycogen is extracted by water is largely 
 dependent upon the degree to which the minuteness of subdivision 
 of the liver-substance has been carried, as the following experi- 
 ment, taken in conjunction with the one that has been given, con- 
 tributes to show. 
 
 A portion of the liver of a freshly killed rabbit was plunged into 
 boiling water for the purpose of checking the loss of glycogen by 
 post-mortem change. It was then pounded in a mortal-, and after- 
 wards still further reduced to a finely-divided state by being forcibly 
 squeezed through muslin. A weighed quantity was now boiled with 
 successive portions of water until no appearance of lactescence was 
 observed. The treatment with boiling water was repeated on the 
 second daj-, and again on the third. After the third day's extraction, 
 
124 i;enei!AL delations of glycogen in liver. 
 
 the residue was oiico more thoroughly poundod, iind again boiled 
 witli water. The extract yielded was strongly lactescent, notwith- 
 standing that the liquid at the end of the previous washing was per- 
 fectly clear. After this further extraction, the residue was boiled 
 with potash, and the glycogen precipitated by alcohol and quantita- 
 tively determined in the usnal way. The following arc the results 
 
 that were obtained : — 
 
 Por 1000 
 of liver. 
 
 Glycogen extracted on the 1st day 36-629 
 
 2nd 7156 
 
 3rd „ 1-904 
 
 „ ,, ,, 3rd ,, after further pounding 6'107 
 „ remaining in the residue 6540 
 
 The presence of acetic acid appears to jiromote extraction. A 
 second portion of the liver made use of in the preceding experiment 
 was extracted with successive portions of water containing O'O per 
 cent, of acetic acid. As will be seen from the subjoined figures, 
 more glycogen was extracted than where water alone was employed. 
 
 Per 1000 
 of liver. 
 
 Glycogen extracted on the 1st day 43'533 
 
 '2nd „ 8-085 
 
 3rd „ 2-421 
 
 ,, ,, ,, 3rd ,, after further pounding 2"097 
 
 ,, remaining in the i-esidue 1620 
 
 It is a point worthy of note that, notwithstanding the diflBculty 
 with which extraction is effected by water at 100° C. (212° F.), the 
 whole of the glycogen is readily and speedily extracted when the 
 operation is performed under pressure in a digester worked at a 
 temperature of about 140° C. (284° F.). Half an hour is found to 
 suffice for the purpose, as will be seen by reference to the subjoined 
 results obtained in two experiments in which a comparison was made 
 through the application of the potash process. Two rabbits were 
 taken, and the livers removed and treated with alcohol for the extrac- 
 tion of the sugar. In each case duplicate portions were submitted 
 to comparative examination with the use of the high pressui-e digester 
 
AMOUNT OF GLYCOGEN IN LIVER. 1"25 
 
 (autoclave) and the application of tlie ordinary potash process. The 
 following were the figures yielded : — 
 
 Glycogen per 1000 of livei'. 
 
 Obs. 1. Obs. 2. 
 
 After half an hour's aqueous 
 
 extraction at 140° C 93-015 68'040 
 
 After boiling with 10 per cent. 
 
 potash for half an hour .... 91'314 .... 64"242 
 
 Coitsidcratidiis rcgardiiiij the Amuitnt of Glijcotjen in tin' Liver. 
 
 The amount of glycogen encountered in the liver presents a wide 
 range of variation. It is governed not only by influences in operation 
 during life, but also by influences coming into operation after death. 
 The former have been in part already referred to, and will be further 
 referred to later on. As regards the latter, the position that we have to 
 deal with is this : the liver, like other parts of the system, contains a 
 certain amount of carbohydrate. The amount, however, in the liver 
 is, under ordinary circumstances, much larger than that found else- 
 where. In form, it mainly consists of glycogen, but, precisely as 
 elsewhere, there is present a certain small proportion of sugar. The 
 carbohydrate susceptible of extraction by alcohol, which is reckoned 
 as sugar, here presents a cupric oxide reducing capacity below that 
 of glucose, and sometimes even considerably below that of maltose. 
 In the latter case, something of a dextrin-like nature must obviously 
 be present. 
 
 The glycogen is placed under conditions which lead to its speedy 
 transformation into dextrin and suga)- after death, and, unless pre- 
 cautionai-y measures are adopted to check this post-mortem trans- 
 formation, a loss of glycogen in proportion to the dextrin and sugar 
 produced will occur. In order, therefore, to obtain a representation 
 of the amount of glycogen existing at the time of death, it is neces- 
 sary either to instantly check post-mortem change, as by rapidly 
 plunging the liver of a suddenly killed animal into a freezing mixture, 
 or else to make allowance for the glycogen which has disappeared by 
 conversion into sugar subsequently to death. 
 
 Where the liver is taken after having been dealt with in a manner 
 to prevent the post-mortem production of sugar, the result given by 
 
12B AMOUNT OF GLYCOGEN IN LIVEl!. 
 
 analysis represents tlie amount of glycogen corresponding with that 
 existing during life, associated with the sugar also naturally belong- 
 ing to life which may be said ordinarily to amount to from 2 to 3 per 
 1000. Where, on the other hand, the organ is taken for examination 
 m an ordinary way, a less amount of glycogen than there should be 
 IS given, whilst the sugar accompanying it may be found, according 
 to the extent to which post-mortem change has occurred, to amount to 
 8, 10, or 12, or from this to 15, 20, or even, it may be, 25 per 1000. 
 Deduction of the amount of sugar naturally belonging to the liver 
 during life, which I have put at from 2 to 3 per 1000, from that 
 found when post-mortem change has not been checked will give the 
 amount produced after death, which stands equivalent to the amount 
 of the transformed glycogen. From these data it is possible, in the 
 case of the liver taken iu an ordinary manner for examination, to 
 estimate, with a close approximation to the truth, the amount of 
 glycogen existing at the moment of death. No mattei', then, whether 
 the liver be taken with special precautions to prevent loss of glycogen 
 from post-mortem transfoi'matiou or not, an estimation of its amount 
 may be made with sufficient accuracy to admit of physiological con- 
 clusions being drawn. 
 
 It must be borne in mind that it follows from what was said in the 
 section of this work on " the glucoside constitution of proteid 
 matter " that the analytical results taken as expressive of glycogen 
 iliclude the cleavage carbohydrate liberated by the potash process 
 adopted. The amount of this material is, however, too small to affect the 
 validity of the conclusions deducible from the results, where glycogen 
 to any significant extent is pi-esent. It stands otherwise, it must bo 
 said, where only insignificant figures are yielded. These, in reality, 
 may be either wholly or partially due to cleavage carbohydrate, and 
 thus ai'e not to be read as necessarily implying that any glycogen is 
 actually present. 
 
 The matei'ial before me, serving as the basis of the remarks about 
 to be made upon the amount of glycogen found in the liver under 
 various conditions, consists of upwards of 200 quantitative estima- 
 tions, extracted from my laboratoi-y books. These 1 do not put 
 forward as exhaustive of the matter, but they suffice to afford indica- 
 tions of a general nature. 
 
 In the process of analysis, the carbohydiate is estimated in the 
 
AMOUNT OF GLYCOGEN IN LIVEK. 127 
 
 form of glucose, but since the body to be represented is one of the 
 composition CeHn.Os instead of CeHuOc, it follows that the result 
 must be mnltiplied by 09 in order to obtain an expression of the 
 true amount of glycogen present. With the figures that follow this 
 has been done. 
 
 A survey of the results shows the existence of a wide range of 
 variation in the glycogen figures that have been obtained. The 
 lower limit may be placed as low as 1 or 2 per 1000, or possibly, even 
 less. The amounts commonly found range from 4 or 5 to 20 or 30 
 or even 40 per 1000. Such figures as 60, 70, and 80 per 1000 are not 
 unfrequently met with, and I have come across amounts as large, for 
 example, as 120, 122, and 126 per 1000. These last quantities were 
 found in dogs which had been specially supplied with food rich in 
 carbohydrates. The animals yielding respectively the figures 120 
 and 122 per 1000 had been kept for some days upon a diet of sugar, 
 bread, meat, and milk ; and the one which gave 126 per 1000, for ten 
 days upon bread and meat. The amount standing next was 114 per 
 1000. It was yielded by a rabbit which had been taken without any 
 special feeding. 
 
 Of the various conditions affecting the amount of glycogen in the 
 liver the most potent is food. Reference has already been made (p. 
 113, et seq.) to the influence of carbohydrate food in leading to an in- 
 creased production and accumulation of glycogen, and nothing further 
 need here be said with regard to it. 
 
 The liver of the young animal, whether taken in the foetal stage 
 or subsequently, a2)pears to contain more glycogen than is found in 
 later life. Amongst my laboratory records I find an instance in 
 which a dog had been kept for some days upon a diet of meat and 
 sugar, for the purpose of ascertaining the condition of the organs in 
 relation to glycogen. When killed, it was found to be in pup, and 
 the organs of the foetus, as well as those of the parent, were ex- 
 amined. 
 
 The liver of the parent, taken in an ordinary way after death, 
 yielded 27 per 1000 of glycogen, accompanied with 22 per 1000 of 
 sugar. The livers of the two foetal pups examined showed respec- 
 tively the presence of 59 and 63 per 1000 of glycogen, with 8 and 7 
 per 1000 of sugar. 
 
 I have also records of the condition existing in two cats with suck- 
 
128 AMOUNT OF GLYCOGEN IN LIVEK. 
 
 ing kittens. In one case tlie liver of the parent yielded 31 per 1000 
 of glycogen, and flie livers of the kittens, taken together, 42 per 1000. 
 No determination of the sugar was made in this instance. In the 
 other, the liver of the parent was found to contain 21 per 1000 of 
 glycogen, accompanied with 21 per 1000 of sugar, whilst the liver of 
 one kitten yielded 32 per 1000 of glycogen with 17 per 1000 of 
 sugar, and that of another 45 per 1000 of glycogen with 10 per 1000 
 of sugar. 
 
 The condition of the liver in different animals in relation to 
 glycogen may next be referred to. I have before me the results of a 
 numbei' of obsei'vations which have been from time to time con- 
 ducted. These I will consider in groups arranged under the heads 
 of the several kinds of animals examined. It will be understood that 
 the animals at the time of being taken were under ordinary con- 
 ditions, and that in the great majority of Ihe instances the examina- 
 tion was conducted in an ordinary way without the observance of 
 special precautions for checking 'post-mortem change. Under these 
 circumstances, allowance has to be made for the loss of glycogen 
 occurring as a post-morttm event, and in order that this may be done 
 the figures representing the sugar will be inserted after those expres- 
 sive of the glycogen found. In a certain number of the instances 
 the liver was taken after having been plunged instantly after death 
 into a freezing mixture, whereby the loss of glycogen hy post-mortem 
 change was prevented. 
 
 Dog. — In many of the observations before me, referring to this 
 animal, there had been a special dieting with carbohydrate food. 
 These observations do not properly fall within what is intended to be 
 here represented, and they will therefore be excluded from consider- 
 ation, with the remark that the figures expressive of glycogen were 
 largely in excess of those yielded by the liver under the ordinary diet 
 of animal food. In nine instances of dogs fed only upon meat the 
 livers gave glycogen figures as follows:— 3'3 per 1000 (with 17 per 
 1000 of sugar), 4-2 per 1000 (with 14 per 1000 of sugar), 5-5 per 
 1000 (with 5 per 1000 of sugar), 87 per 1000 (with 19 per 1000 of 
 sugar), 8-9 per 1000 (with 13 per 1000 of sugar), 12-2 per 1000 
 (with 16 per 1000 of sugar), 18-0 per 1000 (with 6 per 1000 of 
 sugar), 26-4 per 1000 (with 17 per 1000 of sugar), and 39-6 per 1000 
 (with 19 per 1000 of sugar). 
 
AMOUNT OF GLYCOGEN L\ LIVElt. 129 
 
 Cat. — I have a record of a large number of observations upon 
 this animal. In some instances there had been special dieting 
 with bread and milk along vrith the meat, and with reference to 
 these special instances I consider I need not say more than that 
 most of the results failed to show an increase of glycogen to any- 
 thing like the same extent as that noticed in many of the livers of 
 dogs fed in a similar way. In one case, howevei', the glycogen figures 
 stood at Go'ii per 1000 (with 5 per 1000 of sugar), and in another at 
 58'6 per 1000 (with 19 per 1000 of sugar). In most of the instances 
 they were quite low. 1 cannot undertake to reconcile the discrepancy 
 which has been referred to, but the suggestion may be thrown out 
 that possibly the cats may not have properly taken the bread and 
 milk provided. In the twenty-four in.stances where it is recorded 
 that the animals had been kept upon meat only, the glycogen figures 
 varied from 18 per 1000 (with 16 per 1000 of sugar) to 35'3 per 
 1000 (with 21 per 1000 of sugar). Only in a few cases did the 
 glycogen figures, taken irre.spectively of the sugar, stand higher than 
 20 per 1000, and in more than half they stood under 10 per 1000. 
 
 Ixabhit. — Twenty-nine observations, including fourteen in which the 
 liver had been frozen instantly after death. The highest glycogen 
 figures stood at 114-1 per 1000 (with 2-4 per 1000 of sugar). Next 
 to these were 93-1 per 1000 (with 26 per 1000 of sugar), 81-8 per 
 1000 (with 1-1 per 1000 of sugar), and 78-5 per 1000 (with 2-1 per 
 1000 of sugar). In five other cases the glycogen figures, taken 
 alone, were in excess of 50 per 1000. The lowest figures obtained 
 were 5-2 per 1000 (with 4-6 per 1000 of sugar), 5-8 per 1000 (with 
 15'2 per 1000 of sugar), and 7-3 per 1000 (with 2-8 per 1000 of 
 sugar). The others ranged between these extremes. 
 
 Bullock, — Two observations. Glycogen figures yielded — 21 '0 per 
 1000 (with 24 per 1000 of sugar), and 59 per 1000 (with 15 per 
 1000 of sugar). 
 
 Calf. — Two observations. Glycogen figures yielded — 22'0 per 1000 
 (with 21 per 1000 of sugnr), and 130 per 1000 (with 14 per 1000 of 
 sugar). 
 
 Slieq). — Eight observations. In two, where the animals had been 
 specially fed, under my directions, upon barley-meal for three days 
 previous to being slaughtered, the glycogen figures obtained stood 
 only at 13 per 1000 (with 10 per 1000 of sugar), and 3-4 per 
 
130 AMOUNT OF GLYCOGEX IX LIVER. 
 
 1000 (with 15 per 1000 of sugar). In four, where the animals had 
 been specially fed upon maize for two days before death, the livers 
 yielded glycogen figures as follows : — 8-2 per 1000 (with 17 per 
 1000 of sugar), 111 per 1000 (with 15 per lOOO of sugar), 11-5 
 per 1000 (with 25 per 1000 of sugar), and 21-4 per 1000 (with 
 25 per 1000 of sugar). In the other two, in which I have no 
 record of the nature of the food, and in which the liver was kept 
 for some considerable time before being examined, the glycogen 
 figures stood respectively at 6-0 per 1000 (with 23 per 1000 of 
 sugar), and 09 per 1000 (with 30 per 1000 of sugar). 
 
 Pig. — Two observations. Glycogen figures yielded — 60 per 1000 
 (with 13 per 1000 of .sugar), and 8-2 per 1000 (with 7 per 1000 of 
 sugar). 
 
 Horse. — Six observations. In two, nothing is recorded about the 
 condition of the animal or the nature of the food. The glycogen 
 figures yielded stood at 30'0 per 1000 (with 16 per 1000 of sugar), and 
 ll'S per 1000 (sugar not determined). In two others, the remark is 
 entered that the animals were in poor condition, and had been fed on hay. 
 The figures representative of glycogen stood at 12'8 per 1000 (with 
 12 per 1000 of sugar), and H'O per 1000 (with 3 per 1000 of sugar). 
 The remaining two animals had been specially fed upon maize for two 
 days before being killed. One is described as being old and in bad 
 condition, and here the glycogen figures obtained were 29'5 per 1000 
 (with 15 per 1000 of sugar) ; the other was in fair condition, and in 
 this instance the glycogen figures yielded were 73'1 per 1000 (with 
 20 per 1000 of sugar). 
 
 The conditions ordinarily attaching to the butcher's slaughter- 
 house are not such as to conduce to the liver being found rich 
 in glycogen. There is, for instance, the more or less prolonged 
 interval between the withdrawal from the accustomed conditions of 
 the stall or pasture and the arrival at the market, with the fatigue 
 incidental to the journey. Then, there is the indefinite period of deten- 
 tion in the slaughterhouse. And, finally, the liver, after death, is 
 likely to remain for a longer time under conditions permitting of loss 
 of glycogen by post-onortem transformation than is allowed to be the 
 case in the laboratory. 
 
 In the case of the horse the amount of glycogen is seen to range 
 higher than in that of the animals from the butcher's slaughterhouse. 
 
AMOUNT OF GLYCOGEX IN LIVEE. 131 
 
 It appears from the statements of other observers, that horseflesh is 
 coincidently rich in glycogen. Apart, however, from any specific 
 difference that may exist, there is the point for consideration that the 
 horse has usually been less imnaturally circumstanced previous to 
 death than the other animals in question, on account of its not having 
 had to undergo the sufferance involved in passing thi-ough the mai'ket. 
 Although, it is true, many horses are killed on account of old age, or, 
 it may be, some internal disease, yet it frequently happens that the 
 animal is merely disabled from work by a local affection of the legs, 
 which need not derange its general health. 
 
 Domestic Fowl. — One observation. Glycogen figures yielded — 2'4 
 per 1000 (with 3-8 per 1000 of sugar). 
 
 Grouse. — One observation. Glycogen figures yielded — 1'7 per 1000 
 (with 37 per 1000 of sugar). 
 
 Tortoise. — Two observations. Glycogen figures yielded — 21'7 per 
 1000 (with 2-2 per 1000 of sugar), and 86-7 per 1000 (with 1-4 per 
 1000 of sugar). 
 
 Frog.— One observation. Glycogen figures yielded — -i^'S per 1000 
 (with 1-7 per 1000 of sugar). 
 
 Cod-fish. — Two observations. Glycogen figures yielded — 1'8 per 
 1000 (with 1-5 per 1000 of sugar), and 4-0 per 1000 (with 2-6 per 
 1000 of sugar). 
 
 Macherel. — One observation. Glycogen figures yielded — 2"2 per 
 1000 (with 3-0 per 1000 of sugar). 
 
 Salmon. — One observation. Glycogen figures yielded — 0'4 per 1000 
 (with 3-6 per 1000 of sugar). 
 
 Lobster. — Three observations. Glycogen figures yielded — 30 per 
 1000 (with 2-0 per 1000 of sugar), S'O per 1000 (with 3-4 per 1000 
 of sugar), and 20 per 1000 (with 2-5 per 1000 of sugar). 
 
 Croi. — Two observations. Glycogen figures yielded — 27 per 1000 
 (with 81 per 1000 of sugar), and 8-3 per 1000 (with 4-6 per 1000 of 
 sugar). 
 
 Oyster. — Five observations. Glycogen figures yielded — 27'5 per 
 1000 (with 2-3 per 1000 of sugar), 9-9 per 1000 (with 2-2 per 1000 
 of sugar), 27-2 per 1000 (with 1-5 per 1000 of sugar), 41-4 per 1000 
 (with 2-8 per 1000 of sugar), and IS'o per 1000 (with 4-5 per 1000 
 of sugar). 
 
 Mussel {Mytilus edulis). — One observation. Glycogen figures 
 yielded— 17-4 per 1000 (with 1-9 per 1000 of sugar). 
 
132 
 
 THE LIVER IN RELATION TO SUGAR. 
 
 Haviug dealt with the carbohydrate matter which exists in the 
 liver under the form of a material insoluble in alcohol and devoid of 
 cupric oxide reducing power — that is, a material comprehended under 
 the term glycogen — I have next to treat of the carbohydrate matter 
 soluble in alcohol, possessed of cnpric oxide reducing power, and 
 comprehended tinder the general term sugar. This latter, whilst 
 forming a constituent of the liver, is likewise, as will further on be 
 shown, found to be present universally throughout the tissues and 
 organs of the animal system, as far as they have been examined. 
 
 If the carbohydrate now being considered is merely subjected to 
 the ordinary processes of sugar detection and sugar determination, the 
 information is not j-ielded that is necessary for supplying a know- 
 ledge of its character, or form. It would under the circumstances 
 presumably be taken as consisting of glucose, whilst in reality the 
 form of sugar present might be different. If, however, it is subjected 
 to the process of examination to which I have resorted in my investi- 
 gations, a process which embraces the determination of the cupric 
 oxide reducing power before and after boiling with sulphuric acid, 
 data ai-e afforded for supplying more extended information, and it 
 may be found that, instead of glucose, we are dealing with a product 
 of lower cupric oxide reducing power. The cupric oxide reducing 
 power, indeed, that in different instances may be met with is found to 
 vary from a low one upwards, in the manner that would occur from 
 the presence of mixtures of dextrins and sugars. Although, as is 
 obvious, the carbohydrate material present cannot, when possessing a 
 cupric oxide reducing power below that of maltose, be entirely com- 
 posed, strictly speaking, of sugars, yet for physiological purposes it 
 may, for the sake of convenience and brevity, be broadly compre- 
 hended under the term. 
 
 With these preliminary remarks, I will proceed to the consideration 
 of the relation of the liver to sugar taken in the sense just defined. 
 
ANTE-MORTEM AXD POST-MORTEJI STATES. 133 
 
 Examination of the liver reveals tlie existence of a certain amount 
 of sugar. The amount found varies according to the conditions 
 under which the examination is made. If the organ be taken in such 
 a manner as to leprcsent as closely as possible the condition belong- 
 ing to life, the sugar met with is insignificant iu amount, whilst, if 
 time be allowed to elapse betweeu the death of the animal and the 
 removal of the liver, sugar is found to be larg'ely present. 
 
 In I860, through a communication presented to the Royal Society 
 and published in the ' Transactions ' for the following year, I brought 
 under notice the difference existing in the condition of the liver taken, 
 on the one hand, at the moment of death, and, on the other, a short 
 time afterwards. 
 
 Previou.sly, from the time of the promulgation of Bernard's glyco- 
 genic theory, the strongly saccharine condition of the liver met with 
 under ordinary examination after death had been looked upon as 
 representing the condition normally existing during life. I had, a 
 short time before, made the discovery that the blood of the right side 
 of the heart was not in the sacchai'ine condition during life that had 
 been previously inferred from the examination of blood removed in 
 an ordinary manner after death. Although I had thu.s recognised 
 the difference in the anfe-inortem and ordinai'y post-mortem states of 
 the blood, yet, in common with others, I had not at the time any idea 
 that the saccharine state of the liver revealed under the method of 
 examination then adopted was likewise due to a post-mortem change. 
 Not being able to understand how the difference in the two states of 
 the blood was to be accounted for, I was driven to look to the liver in 
 search of an explanation. I first tried the effect of injecting blood at 
 different pressures through the organ after death to imitate different 
 states of blood pressure in the vessels, and ascertain if this influenced 
 the escape of sugar. On failing to obtain any satisfactory informa- 
 tion from these experiments, the idea occurred to me to subject the 
 liver to examination to see whether there might not be the same 
 difference between the ante-mortem, &ndi post-mortem states as had been 
 noticed in the blood. I did not start with the expectation that any. 
 thing would issue from submitting the question to the test of ob- 
 servation, but I nevertheless considered the matter worthy of trial, 
 and hence resolved to endeavour to obtain from the liver a repre- 
 sentation approaching as closely as possible to that of the actual 
 
13i THE LIVER IN RELATION TO SUGAK 
 
 living state, by supplying conditions at the instant of death to pre- 
 vent the occurrence of post-mortem change in relation to sugar. 
 
 It was known that the liver contained a substance susceptible of 
 rapid transformation into sugar by ferment action, and that a ferment 
 capable of effecting the transformation was present. The object, 
 therefore, to be attained was to deprive the ferment of activity at the 
 instant of death. 
 
 In my first experiments I sought to effect this by injecting a strong 
 solution of potash into the liver through the portal vein. As the 
 result, traces only of sugar were afterwards found m the organ. 
 
 Subsequently, I resorted to a method of experimenting in which 
 the desired object of checking post-mortem ferment action was at- 
 tained through the simple jjhysical agency of alteration of tempera- 
 ture. By sufficiently elevating the temperature, the ferment is 
 coagulated and its activity destroyed, whilst, by sufficiently lowering 
 it, ferment action is suspended. 
 
 Plunging a portion of liver, excised as quickly as possible after 
 death, into boiling water leads to the destruction of the ferment, and 
 thus prevents any subsequent production of sugar. Obviously, how- 
 ever, the effect of increase of heat up to a point short of that neces- 
 sary for the destruction of the ferment will be to promote trans- 
 formation, and it must be borne in mind that with a thick mass of 
 liver an appreciable amount of time will be required for the effectual 
 penetration of the heat to the deeper portion, in which the oppor- 
 tunity will thus be given for the occurrence of a certain amount of 
 change. In spite of this circumstance, I found, on performing the 
 experiment, that the condition presented by the liver in relation to 
 sugar stood in striking contrast to that which had been previously 
 supposed to belong to it. 
 
 By immersion, on the other hand, in a freezing mixture, as of ice 
 and salt, ferment action is checked, without the ferment being 
 destroyed. Contrary to what occurs with the application of heat, the 
 effect of exposure to cold operates continuously in the desired direc- 
 tion, the energy of the ferment being diminished in proportion as the 
 temperature is lowered, until it is brought to a state of inactivity. If 
 the liver to be examined is only of moderate thickness, as is the case 
 with that of the rabbit, it will become frozen throughout with suffi- 
 cient rapidity to effect what is wanted ; but if a thick mass of 
 
ARKEST OF ?0,ST-JI0ETE1I CHANGE. 135 
 
 material hais to be dealt with, such as occurs with an excised portion 
 of the liver of a dog, a few incisions should be made across it to pro- 
 mote the more rapid penetration of the freezing influence. 
 
 Upon the grounds just stated, it will be intelligible that, of the two 
 methods of checking post-mortem change, that by freezing may be 
 regarded as preferable ; but it must not be forgotten in its ap- 
 plication that the ferment has not undergone destruction, and that, 
 therefore, the capacity for sugar production still exists, and will come 
 into play should the opportunity be given, in the succeeding processes 
 of preparation for examination, for it to do so. Observation, in fact, 
 shows that a piece of frozen liver which has been allowed to thaw 
 and is afterwards set aside at an ordinary temperature contains in 
 some hours' time about as much sugar as a piece of the liver which 
 has not been frozen. 
 
 The ice and salt mixtui-e employed should be prepared about half 
 an hour before it is wanted for nse, in order that the occurrence of a 
 certain amount of liquefaction may place it in a favourable position 
 for acting rapidly upon the immersed piece of liver. A minute or 
 two will then be found to suflSce for bringing the specimens into a 
 hard, frozen state. 
 
 At the now distant period when this method of experimenting was 
 initiated, the subsequent treatment of the frozen liver consisted 
 simply in the preparation of a decoction and the examination of this 
 for sugar by boiling in a test-tube with the copper solution. For the 
 preparation of the decoction, thin slices were pared off the frozen 
 liver and pounded to a pulp in a cooled mortar. 
 
 A capsule with a little water in it was next placed over a flame, and 
 after the water was brought to a brisk state of ebullition, the liver 
 pulp was introduced into it, a little at a time, in a manner to secure 
 the instantaneous destruction of the ferment. After a few minutes, 
 the liquid was strained off, and a portion of it boiled in a test-tube 
 with Fehling's solution, when it was found that, instead of the im- 
 mediate and copious formation of yellow or red precipitate en- 
 countered in examinations of the liver conducted without the 
 observance of the precautions referred to, the contents of the test- 
 tube remained blue, and only after standing exhibited a slight sub- 
 sidence of red oxide particles. 
 
 Such was the method of expei-imenting by which I showed the 
 
lo6 XriE LIVER IN RELATIOX TO SUGAE. 
 
 fallacy of taking tho results of ordinarily conducted examinations of 
 the liver iu a. post-mortem state as representing the condition existing 
 during life. The strongly saccharine condition of the liver, which 
 had been erroneously assumed to represent the physiological state, 
 formed one of the two main points of consideration that led to the 
 evolution of the glycogenic theory propounded by Bernard ; the other 
 main jjoint being the character taken to belong naturally to the blood 
 issuing from the liver, which I shall, later on, show to have been 
 equally founded on error. 
 
 Since the time when my original exjieriments were conducted, con- 
 siderable advance has been made in analytical procedure, and we are 
 now placed in a position to express ourselves in language other than 
 that founded upon the results of mei'e qualitative testing. 
 
 Through exti-action with alcohol, subjection of the product to the 
 inverting action of sulphuric acid, and the employment of the 
 ammoniated cupric test, we can now not only express in definite 
 numerical terms the precise amount of sugar existing, but also indi- 
 cate the nature of the sugar that is present. 
 
 In the application of quantitative determination to the frozen 
 liver, the process to be adopted is as follows : a weighed portion of 
 the pulp obtained by pounding in a cooled mortar is treated with 
 alcohol in a manner to secure the thorough extraction of the sugar. 
 Once thoroughly permeated by alcohol, the liver substance is no longer 
 in a condition to undergo change. Through the influence exerted by 
 the spirit, the ferment is thrown into a state of suspended activity. 
 After dividing the product of alcoholic extraction into two portions, 
 one is titrated at once with the ammoniated cupric test, whilst the 
 other is titrated after having been previously subjected to the in- 
 verting influence of sulphuric acid. From the two sets of figures 
 obtained information is given concerning the character of the sugar 
 pi'esent. 
 
 The amount of sugar encountered in the experiments that I have 
 conducted, in the manner described, upon the dog, cat, and rabbit, 
 has been found to stand at about 2 to 3 per 1000, but I have amongst 
 my records instances in which it was found to stand as low as about 
 1 per 1000. If the removal and freezing of the liver have not been 
 expeditiously performed, higher figures must bo looked for. 
 
 The amount of sugar, on the other hand, ordinarily encountered in 
 a liver removed a few minutes after death, and not subjected to 
 
AMOUNT OF SUGAR IN LIVEIi DURINR LIFE. 137 
 
 special treatment for the aiTest of ferment action, may be said to 
 stand at somewhere about 12 to 15 per 1000; more will be found as 
 time goes on, and, after the lapse of 18 to 24 hours, the quantity 
 ordinarily met with amouuts to from about 20 to 30 or 35 per 1000. 
 Naturally, the amount will vary, according to the circumstances, as 
 regards temperature, &c., existing. A necessary factor for the 
 occurrence of sugar production is, of course, the presence of glycogen, 
 but 1 think it may be said that when glycogen is present in very 
 large quantity the production proceeds less actively and less exteti- 
 sively than when it exists in moderate amount. It seems as if the 
 ferment power became lessened by the large accumulation existing. 
 Apparently, a more active production occurs where the liver is allowed 
 to remain full of blood after the destruction of life than where the blood 
 has been permitted speedily to escape from the vessels. The amount 
 of sugar found after the lapse of a few minutes from death as cpm- 
 pared with that found after the lapse of several hours shows that the 
 production proceeds with much greater activity at first than it does 
 later on. 
 
 As representative examples of the state existing at the moaaent of 
 death, I may give the results of four experiments performed in the 
 Research Laboratories of the Royal Colleges of Physicians and 
 Surgeons whilst the manuscript for these pages was in course of 
 preparation. Four healthy good-sized rabbits were taken, without 
 selection, from a hutch. After death by jiithing, the livers were as 
 expeditiously as possible removed and plunged into a freezing- mix- 
 ture, and subsequently dealt with in the mannei' that has been 
 described. 
 
 Amount and Nature of Sugar found in the Liver promptly removed and 
 frozen. 
 
 Cupric oxide reducing 
 power of the sugar 
 Sugar per 1000, present, in relation to 
 
 expressed as that of glucose 
 
 glucose, at 100. 
 
 Rabbit A I ^f °™ sulphuric acid. . 1-601 1 7. 
 
 L after ,, „ .. 2-142 J 
 
 ^'^^^^^ {a^" ;; ;;:: lit Y^ 
 
 K^b^'^c {a^r ;: ;::: \^ }«« 
 
 K^b"'*^ {a^" ;; ;;:: \Z Y' 
 
138 
 
 THE LIVER IN RELATION TO SUGAR. 
 
 To give completeness to the experiments, quantitative determina- 
 tions of the glycogen were made, and the amounts found stood as 
 follows : in rabbit A, 76 ; B, 59 ; C, 7 ; and D, 114 per 1000. 
 
 I have given examples representative of the state of the liver in 
 relation to sugar at the instant of death. I will now give further 
 examples, also consisting of recently performed experiments, in illus- 
 tration of the difference found to exist in the state of the organ at the 
 instant of death and at subsequent periods. Two rabbits were killed 
 by pithing, rapidly opened, and a portion of the liver of each excised 
 and plunged into a freezing mixture. A few minutes later, the other 
 portion was removed, part of it taken at once for examination, and 
 the remainder set aside until the following day, when it was also 
 taken for analysis. 
 
 Amount and Nature of Sugar in the Liver at the Moment of Death 
 and at subsequent periods, 
 
 Cupric oxide 
 reducing power 
 of tlie sugar 
 Sugar per 1000, present in rela- 
 exprcssed as tion to tliat of 
 
 glucose. glucose at 100. 
 
 Rabbit E. 
 
 7, ,. f before sulphuric acid. . 2'00O l „„ 
 
 ^'•°^™''^"- {after '., „ .. 2 260 } ^^ 
 
 Liver, a few minutes /before „ „ .. 12 '940 1 , 
 
 after death \ after „ „.. 12-940 j- glucose 
 
 Liver, left till the /before „ „ .. 34-340 \ „„ 
 
 foUowingday \ after „ „.. 36 '820 J ^ 
 
 Eabbit F. 
 
 17 r r before „ „ .. 0-980 1 „„ 
 
 ^™="'"^^^"' {after „ „.. 1 -060 } ^^ 
 
 Liver, a few minutes / before „ „ . . 11 -550 1 „- 
 
 after death "[after „ „.. 12-130 J 
 
 Liver, left till the /before „ „ .. 33-280 \ , 
 
 following day t after „ „ . . 32 -530 J g'"<'°"' 
 
 As regards the nature of the sugar, it is to be stated that, whilst in 
 the liver taken ordinarily after death the sugar present is usually 
 in the form of glucose, that met with in the frozen liver is usually, 
 on the other hand, found to possess a cupric oxide reducing power of 
 a lower degree — a cupric oxide i-educing power, indeed, often approach- 
 ing or even, it may be, standing below that of maltose. 
 
 The following are photo- engravings from micro-photographs of 
 
SUGAR OF LIVER AT MO.MENT OF DEATH. 139 
 
 osazoiie crystals yielded respectively by the liver frozen at the 
 instant of death and the liver taken ordinarily after death. 
 
 Osazoiip crvstals frum the sug;ir of a rabbit's liver frozen instantly- after death. 
 Magnified 400 diameters. 
 
140 
 
 THE UVElt IX liELATION TO SFCAK. 
 
 Aciculai- glucosazoue crystals from the sugar of a clog's liver taken in an 
 ortlinary way after death. Magnified 400 diameters. 
 
 Whilst it is necessary, in dealing -with tlie liver of tlie warm- 
 blooded animal, to observe the precautions which I have particular- 
 ised in order to obtain a correct representation of the state belonpfing 
 to life, in the case of that of the cold-blooded animal the conditions 
 are such as not to require that similar expedients should be had re- 
 course to. With the low body temperature existing, there is not the 
 same rapid jpost-mortem production of sugar occurring, and, if no un- 
 necessary delay is permitted, an ordinarily conducted examination 
 suffices. Subjoined are examples of the condition met with in 
 animals of this kind, and I will allow the figures to speak for them- 
 selves, 
 
LIVEK OF COLD-BLOODED AJflJIALS. l4l 
 
 Amuu)d and Nature of Sugar in Livers of Gold-bluuded Animals. 
 
 Gupric oxide 
 
 reduciug power 
 
 of the sugar 
 
 Sugar per 1000, present in rela- 
 
 expressed as tion to that of 
 
 glucose. glucose at 100. 
 
 Meptile. 
 
 rr. . • f before sulphuric acid 1 '250 1 ,- 
 
 Torto.se. I ^fj^^ 1 2.^70 J5, 
 
 „, , - /before ., „ 0-852 1 .,, 
 
 lortoise. 1 ,-, 1 ,,n- fM 
 
 \ after ., 1 iii J 
 
 Aiiipliibiaii. 
 
 T, r before „ „ 1 -316 l -^ 
 
 ^'■°g---i after „ „ 1-724 \ '*" 
 
 The above three observations were conducted during an October 
 month. The temperature -vvas mild for the time of year. The 
 animals were killed, and the livers afterwards in an ordinary way 
 removed and submitted to analysis. In the case of the frog, fifteen 
 livers were taken for the anal^'sis conducted. A large amount of 
 glycogen in each of the observations was found to exist. 
 
 The frog may be made use of to exemplify the modifying influence 
 exerted by the body-temperature existing at the time of death upon 
 the results obtained from an ordinarily-conducted examination of the 
 liver. The above figures were derived fi-om frogs exposed to ordinary 
 conditions in an atmosphere, as stated, of medium temperatiu'e. A 
 different result .vould have been obtained if, previously to death, the 
 body-temperature had been raised, as is susceptible of being done, 
 by placing the animal in an artificially-heated atmosphere. Under 
 these circumstances, the liver is found to stand in a position corre- 
 sponding with that of the warm-blooded animal. 
 
 I have referred to this matter in my previous writings, and in 
 these writings I cited an experiment in which I exposed frogs for a 
 couple of hours to the influence of a temperature of 32° C. (90° F.). 
 An examination of the livers, conducted in the ordinary way, revealed, 
 with the employment of Fehliug's solution, the presence of a notable 
 amount of sugar, whilst the livers of a duplicate set of frogs which 
 had not been similarly exposed to the elevated temperature failed to 
 give evidence of a similar nature. 
 
 The phenomenon to which I have been alluding did not escape the 
 
142 
 
 TJIE LIVER IN llELATION TO SUGAI!, 
 
 notice of Bernard. In the ' Comptes Rendus ' of the Academy of 
 Sciences, March, 1857, he stated that by lowering the temperature of 
 a batch of frogs sugar may be made to disappear from the livei-, 
 and that on aftei'vvai'ds exposing them to warmth it is found to 
 reappear. He adds that it is possible to produce this singular alter- 
 nation of appearance and disappearance of sugar several times, 
 without any food being given, solely by acting upon the circula- 
 tioa through the medium of temperature. Whilst thus noticing 
 the fact, Bernard missed its true interpretation, which is connected 
 not in reality with life activity, but with activity coming into opera- 
 tion after death and contingent upon the temperatui'e that may 
 happen to exist. 
 
 Oupric oxide 
 reducing power 
 of the sugar 
 Sugar per 1000, present in rela- 
 expressed aa tion to that of 
 
 glucose. glucose at 100. 
 
 Fish. 
 
 p I r before sulphuric acid 1'220 Xm 
 
 ■■ ""[after ,, „ 1 '500 / 
 
 c«'i"-{a^'' ;; ;; ::;::: '^620 }«« 
 
 Macwja^^ ;; ;; ::::;: ^o^ V' 
 
 a , r before ., „ 2-230 1 „, 
 
 Salmon. I ^jj^^. ■ •' 3 .gg^ |61 
 
 The above livers were obtained from the fishmonger, and were 
 therefore derived from animals which had been for some time dead. 
 As often happens with livers obtained from the various animals 
 employed for consumption as food the total amount of carbohydrate 
 matter was found to be small. Unless glycogen is present in quan- 
 tity at the time of death, there is not the source for a large amount 
 of sugar, and, in the case of the fish in question, the amount of 
 glycogen found associated with the sugar was small, ranging below 4 
 per 1000. 
 
LIVER OF INVERTEBRATE ANIMALS. 
 
 143 
 
 Crustacean. 
 Lobster . . 
 Lobster . . 
 Crab . . . . 
 Crab . , . , 
 
 s 
 
 ugar per 1000, 
 expressed as 
 
 
 glucose. 
 
 luric acid . 
 
 .. 1-730 
 . . 1 -980 
 
 
 .. 2-150 
 . . 3 -400 
 
 
 .. 7-250 
 .. 8-100 
 
 
 .. 6-600 
 .. 8-280 
 
 Cupric oxide reducing 
 power of tlie sugar 
 
 present in 
 
 relation to that of 
 
 glucose at 100. 
 
 Is? 
 
 I after 
 
 r before 
 ' ■ \ after 
 
 f before 
 ■ ■ \ after 
 
 J before 
 ' " \ after 
 
 It is noticeable that the amount of sugar found iu the case of the 
 crabs was much larger than in that of the lobsters, and it is to be 
 remarked that, whilst the lobsters when taken for examination were 
 in a lively and active state, the crabs, on the other hand, showed 
 scarcely any signs of life. The amount of glycogen present was in 
 each instance small. 
 
 Mollusk. — From the group of the MoUusca I have taken the oyster 
 and mussel for examination. The liver does not here exist in a 
 separate form, as in the higher animals. It is interwoven with other 
 structures, and these were included in what was taken for analysis. 
 So large a proportion of the animal, however, consists of liver that 
 the figures obtained may be regarded as in the main belonging to it. 
 The following are repi*esentative examples drawn from the recorded 
 analyses before me. The animals were taken in the freshly-opened 
 state : — 
 
 Oyster. 
 
 Dutch native . 
 
 {before sulphuric acid 
 after ,, 
 
 Dutch native , 
 
 {before 
 after 
 
 r before 
 ■"[after 
 
 Cookingoyster..{^b;^;;^ 
 
 Mussel. 
 
 / before 
 \ after 
 
 Whitstable native ■ 
 
 Salt-water mussel 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 Cupric oxide reducing 
 power of the sugar 
 
 present iu 
 
 relation to that of 
 
 glucose at 100. 
 
 I.. 1-230 
 . . 2-330 
 
 }- 
 
 . . -730 
 . . 1 -580 
 
 }« 
 
 .. 0-630 
 .. 2-300 
 
 |27 
 
 . . 1 050 
 .. 4-530 
 
 }- 
 
 .. 0-590 
 . . 1 -960 
 
 J30 
 
 From what will be adduced further on (p. 194, ct seq.), when refer- 
 
144 THE LIVEIt IN KELATION TO SUGAR. 
 
 Mice is made to tlie sugar existing in other structmxs of tlie body, it 
 will be seen that, laking the condition at the moment of death, no 
 material difference is discernible between the liver and these other 
 structures. In the spleen, for example, and the pancreas, kidney, 
 brain, lung, placenta, and the same is true of the egg, sugar is 
 invariably to be found ; and, summarily expressed, the amount may 
 be said to vary from about 1 or 2 to 3 or 4, and occasionally more, 
 per 1000. In mi^scle the ordinary range stands rather higher, and 
 quantities of 6 and 7 per 1000, and even beyond, arc sometimes met 
 with. 
 
 Looking, therefore, to the state existing- at the moment of death, 
 we find nothing, as far as sugar is concerned, to lead us to view the 
 liver as standing in a different position from the other sti-uctures of 
 the body. There is this, however, that is distinctive as regards the 
 liver : the amount of glycogen, due to the position in which the 
 organ is placed in relation to ingested cai-bohyd rates, is, under 
 normal conditions, much larger than elsewhere ; and, in addition, 
 there is present, or, it may be, there becomes developed, at death a 
 very energetic sugar-forming ferment. 
 
 It is through the coexistence of these two factors that the capacity 
 exists for the rapid and extensive production of sugar that is noticed 
 at a suitably elevated temperature to occur. As far as the glycogen 
 is concerned, there is the capacity during life, but obviously there 
 must be a restraining or inhibitory intluence in operation preventing 
 the ferment change which occurs after death. It is not permissible 
 to suppose that the same feianent change is taking place during- life 
 that is observed after death, and that the removal of the resulting 
 sugar by the circulation constitutes the only difference existing ; for, 
 apart from other considerations elsewhere adduced in this work, 
 which sufficiently negative such a proposition, the following argu- 
 ment stands in contravention. 
 
 From observation, it may be stated that sugar is produced in the liver 
 during the first few — say ten — minutes after death to the extent of 
 about 10 to 12 per 1000. With an average amount of glycogen present, 
 even assuming the liver of the rabbit to be taken in which the amount is 
 larger than in many other animals, it is shown by calculation (based 
 upon a proportion of 50 per 1000) that the whole would disappear in 
 about three-quarters of an hour if the production of sngar took place 
 
INIliniTIOX OF SUGAK-PUOliUCTION DLUUNG LIFE. Hfi 
 
 at tlie rate above mentioned. Further, in the case of the carnivorous 
 animal, from the smaUness of the amount of glycogen existing, it 
 would sometimes happen that only a limited number of minutes 
 would be required for a total disappearance to occur. It is true that 
 whilst digestion and absorption are going on a formation of glycogen 
 is taking place, which would have a counterbalancing effect. At a 
 period of fasting, however, no such source of production exists, and 
 yet, after a fast of twenty-four or even forty-eight hours, a consider- 
 able amount of glycogen is ordinarily found to be present, it being 
 only after more prolonged fasting that it may be expected to be 
 absent. 
 
 The train of reasoning that I have adduced does not stand upon a 
 mere postulatory basis. Under certain conditions, which may be 
 evoked experimentally, sugar is actually produced in the liver during 
 life. As a result, it reaches the general circulation, and thence the 
 urine, which, thus becomes an indicator of the state of things existing 
 within. Years ago I noticed, and was struck by, the short time 
 sufficing for the liver to lose its glycogen in experiments attended 
 with the artificial production of glycosuria. With animals killed at 
 the end of an hour, or even less, I often failed to observe the presence 
 either of sugar, by rough testing with Fehling's solution, or of 
 glycogen. The inhalation of carbonic oxide, either directly, mixed 
 with air, or indirectly, employed in the form of puff-ball smoke, con- 
 stitutes one of the conditions leading to the production of sugar in 
 the liver and its passage into the blood and urine. I have recentlj-, 
 with the improved methods of analysis now at command, conducted 
 experiments of a quantitative nature. In these, the blood collected 
 at the instant of death showed the presence of an abnormally largo 
 quantity of sugar, the amount standing in one instance as high as 
 4"38 per 1000. The livers were taken without subjection to special 
 treatment, and thus attention required to be given to the amount 
 of sugar present, as well as that of glycogen, in order that loss of the 
 latter from post-mortem change might not escape consideration. In 
 the case of a cat, submitted for a quarter of an hour to the influence 
 of puii-ball smoke, the glycogen figures stood at 5"05 per 1000 and the 
 sugar at 13'69 per 1000, both expressed as glucose. In that of 
 another cat, submitted to similar treatment for half an hour, the 
 glycogen figures stood at 3"10, and the sugar at 494 per 1000. In 
 
14G THE LIVEK IN RELATION TO SUGAR. 
 
 that of a clog, similarly treated for tliree-quarters of an hour, the 
 figures for glycogen were 4'27 per 1000, and for sugar 1'05 per 1000. 
 The position pertaining to life appears to be an anomalous one, 
 but in reality it may be said to be analogous to that which obtains in 
 relation to the coagulation of the blood. Here the factors tending to 
 produce coagulation are prevented normally during life from coming 
 into play, but are permitted to do so after removal of the blood from 
 the vessels. The analogy, even, may be followed further, for con- 
 ditions may arise which permit the blood to coagulate whilst con- 
 tained in the living vessels, and in like manner the liver may be 
 placed under conditions to permit of the manifestation of ferment 
 activity, resulting in the production of sugar, its j^assage into the 
 circulation, and its escajse with the urine. 
 
 Production of Sugar in the Liver after its Bemoval and the Passar/e of 
 a Stream of Water through its Vessels to wash out the Blood. 
 
 It was discovered by Bernard, at an early period of his investiga- 
 tions, that in the liver-substance washed free fi'om blood the capacity 
 exists for the production of sugar. If means be adopted to connect 
 the portal vein with a water-tap, and the tap be turned on, the water 
 passes through the continuing vessels and escapes from the hepatic 
 vein, carrying away the blood, and at the same time sugar and a 
 certain amount of glycogen. During the process the liver becomes 
 enormously swollen and cedematous, and likewise loses its colour. If 
 it is subsequently placed in a position for ferment action to occur, 
 sugar is found to be produced. Whilst such, from Bernard's time, 
 has been known, nothing has hitherto been said about the nature of 
 the sugar that is formed. 
 
 Upon the strength of the collection of results before me, the state- 
 ment may be made that the liver-substance contains a ferment 
 possessing a glucose-forming capacity, but that a variable kind of 
 sugar jDroduct is met with. 
 
 Whilst a product with a cupric oxide -reducing power more or le.ss 
 considerably below that of glucose is ordinarily encountered, glucose, 
 on the other hand, may happen to be found. It has appeared to me 
 as though there has sometimes been an extensive amount of glycogen 
 transformed into a product of low cupric oxide reducing power, and 
 
SUGAR-PRODUCTION AFTER ALCOHOL COAGULATION. l-tT 
 
 at other times a less amouut of material transformed, vvitL the ac- 
 quirement of a higher degree of cupric oxide reducing power. 
 
 The effect of adding blood to the washed liver is to increase 
 materially the amount of sugar produced. As regards the nature of 
 the sugar formed, nothing more definite can be said than that a con- 
 siderable variation has been noticed in the cupric oxide reducing 
 power of the product found to be present. 
 
 Production of Sugar in Liver Substance iireviously Coagulated hy 
 Alcoliol. 
 
 It is liver-substance in a fresh state which has thus far formed the 
 subject of consideration, and nothing is deducible from the informa- 
 tion that has been supplied which can be taken as pointing to the 
 production of sugar being other than the result of simple ferment 
 action independent of connexion with vital activity : an action com- 
 parable to that exerted by the ordinary amylolytic ferments — diastase, 
 ptyalin, &c. The only difference that is presented is that, in the one 
 case, the capacity exists for carrying on the change to the stage of 
 glucose, whilst, in the other, it only exists to a sufficient extent to lead 
 to the production of maltose. 
 
 I now proceed to show that the liver-substance, after subjection to 
 the coagulating influence of alcohol, still retains its capacity for 
 sugar production — a fact which affords absolute proof, if indeed the 
 idea could now exidt in the mind of anyone that proof were wanting-, 
 that the phenomenon is not dependent upon the metabolic power 
 resident in the living cells of the liver. 
 
 After coagulation by alcohol, the liver-substance is not prone to 
 undergo change on keeping, and consequently may be preserved for 
 any length of time in a condition convenient for the purposes of 
 experiment in connexion with the question of ferment action. This 
 question in its bearings upon the liver I have somewhat extensively 
 studied, and in the succeeding pages I will give an account of the 
 results obtained. 
 
 The liver selected for use should be one containing a fair amount 
 of glycogen, and should be taken before loss of glycogen by trans- 
 formation into sugar has been permitted to any marked extent to 
 occur. After being thoroughly reduced to a pulp in a mortar, it is 
 
 L 2 
 
118 THE I.IV'ER IN RELATION TO SUOAI!. 
 
 placed in a sufficiency of alcohol to fully secure coagulation. The 
 alcohol is afterwards strained off, and with it is removed the greater 
 portion of the sugar that may happen to have been present. The 
 coagulated material is now allowed to dry, either spontaneously or 
 over sulphuric acid in a desiccator. Heat must not be employed, 
 unless the temperature be kept below the point at which the ferment 
 becomes destroyed. 
 
 If the liver-substance thus prepared be treated with water and 
 exposed to moderate warmth, change ensues, attended with the pro- 
 duction of sugar. To reveal this sugar-production the employment 
 of an analytical procedure is necessary, and a determination must be 
 made, not only of the amount of sugar in the product at the end of 
 the experiment, but also of the small amount existing in the dry 
 material that escaped removal with the alcohol used in the preliminary 
 step of coagulation : the figares for this requiring to be deducted 
 from the others in order to obtain a representation of the actual 
 amount of sugar produced. 
 
 The process I have mentioned as being in general use in my in- 
 vestigations supplies the iufoz-mation that is wanted. The sugar, 
 after being fully extracted with alcohol, is estimated by titration with 
 the copper test, before and after boiling with sulphuric acid. In this 
 way both its amount and nature are revealed. 
 
 The residue from alcoholic extraction is, in the next place, sub- 
 jected to boiling with potash and treatment with spirit to precipitate 
 the glycogen present. The amount of this is subsequently ascer- 
 tained by conversion into glucose by the agency of sulphuric acid 
 and the employment of the copper test. 
 
 By means of this double process, data are supplied for comparing 
 the gain of sugar with the loss of glycogen, and, if the carbohydrate 
 is expressed throughout as glucose, we have equivalent terms of 
 expression to deal with, permitting the figures on the two sides to 
 be read off as they stand. 
 
 On experimenting in the manner that has been described, we learn 
 that a progressive production of sugar takes place, concurrently with 
 a disappearance of glycogen. In some of the experiments that I 
 have conducted, the change has been observed to advance almost to 
 the point of a complete replacement of the glycogen by sugar. We 
 learn further, it may he said, that a gradual increase of the cupric 
 
SUGAR-PKODUCTION AFTER ALCOHOL COAGULATION. 140 
 
 oxide i-cdiicing power of the sugai' produced takes jilace, until tlie 
 stage of glucose is reached. 
 
 The following tabular representation shows the results obtained in 
 an experiment where the product was examined after varying periods 
 of exposure to a temperature of 38° C. 1'5-gram portions of the 
 dried liver-substance with 20 c.c. of water were placed in separate 
 flasks, and exposed alongside each other for the time specified in the 
 table. They were then removed and submitted to analysis. The figures 
 given to represent the state of the dried liver-substance existing at 
 starting constitute the mean of four analyses, which, it may be re- 
 marked, stood throughout in close accord v.-ith each other. 
 
150 
 
 THE LIVEK IN EELAXION TO SUGAR. 
 
 
 
 
 
 
 
 
 
 
 o 
 
 
 
 
 
 
 
 
 
 o 
 
 
 
 
 
 
 
 
 
 . 3 
 
 £ 
 
 
 - 
 
 ' 
 
 : 
 
 : 
 
 ' 
 
 ' 
 
 
 &0 
 
 
 
 
 
 
 
 q d 
 
 p- 
 
 ira 
 
 
 
 J,, 
 
 CI 
 
 1^ 
 
 
 
 •* 
 
 ^'% 
 
 
 
 
 CO 
 
 tb 
 
 'M 
 
 
 
 
 3 1 
 
 
 9 
 
 9 
 
 9 
 
 9 
 
 9 
 
 
 
 9 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 u 
 
 
 
 
 
 
 
 
 
 P^ 
 
 
 
 
 
 
 
 
 
 bfl 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 <b 'o "o 
 
 
 
 
 
 
 
 
 
 J 3 0) .u 
 
 
 
 
 
 
 
 
 
 n oft 
 ie red 
 ■ of th 
 to tha 
 cose. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 I— 1 
 
 
 
 
 
 
 
 -w 
 
 4J 
 
 •^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 CD ^ 
 
 
 CM 
 
 
 
 t- 
 
 
 00 X:- 
 
 X> 
 
 1-^ 
 
 X 
 
 00 
 
 CO 
 
 
 o 
 
 
 
 
 
 
 
 
 
 .g 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 •^ 
 
 
 
 
 
 
 
 
 
 1=3 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 
 ^ 
 
 ^ 
 
 ^ 
 
 
 
 
 
 
 
 
 
 II -fs 
 
 
 
 
 
 
 
 
 
 bo 
 
 
 
 
 
 
 
 3 -e 3 g 
 
 •^ 
 
 CO 
 
 CO 
 
 10 
 
 CO 
 
 
 
 
 
 <" s-g.-a 
 
 
 to 
 
 03 
 
 
 
 
 
 
 9 ? 
 
 9 
 
 t-l 
 
 
 
 r-l 
 
 
 |1^ 
 
 6 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 S 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ ■ 
 
 
 
 
 
 
 
 
 
 r-J 
 
 
 
 
 
 
 
 
 
 
 3 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 C3 
 
 
 
 
 
 
 
 sis 
 
 SB 
 
 
 
 
 
 
 
 to-*^ -r 
 
 
 
 
 
 
 
 
 
 rgJI 
 
 
 
 
 
 
 CO 
 
 CO 
 
 CO 
 
 
 
 
 
 00 
 
 
 
 
 
 
 9 
 
 9 
 
 9 
 
 9 
 
 
 '7^ 
 
 T' 
 
 £'3' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ='-' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^.-> , 
 
 
 
 
 
 
 
 
 
 "S^ : 
 
 
 
 
 
 
 
 
 
 C3 a> 
 
 
 
 d 
 
 
 
 
 
 
 Sh 3 
 
 
 
 CO 
 CO 
 
 :; 
 
 = 
 
 = 
 
 :; 
 
 ^ 
 
 - « 
 
 
 ^ 
 
 
 
 
 
 
 
 " a. 
 
 
 c 
 
 J 
 
 
 
 
 
 
 00 g 
 
 *3 
 
 
 
 "3 
 
 t, 
 
 £ 
 
 
 
 
 •^£» 
 
 
 
 _g 
 
 3 
 
 
 3 
 
 
 " 
 
 " 
 
 - 
 
 
 
 5 
 
 S 
 
 .^ 
 
 ,fl 
 
 
 
 
 
 _c^ 
 
 
 
 
 (N 
 
 ^ 
 
 CO 
 
 i> 
 
 t- s?^ 
 
 
 
 
 
 
 
 
 
 m ° 
 
 
 ,£ 
 
 ^ 
 
 
 
 
 
 
 J3 Oi 
 
 
 iS 
 
 ~ 
 
 :; 
 
 ; 
 
 ;; 
 
 ; 
 
 ::g;2 
 
 
 t 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 
 
 
 
 
 
 
GLYCOGEN LOSS IX KELATIOX TO SUGAR GAIN. 151 
 
 Tlie figures in tlie columns under the headings of " Sugar, after 
 treatment with sulphuric acid (glucose) " and " Glycogen, expressed 
 as glucose," enable us to compare the gain of sugar with the loss of 
 glycogen. Theoretically, on the assumption that glycogen is simply 
 transformed into sugar, there should be an accord between the two 
 sets of figures, or, in other words, no alteration in the total amount 
 of carbohydrate. Practically, as seen in the table above, which 
 agrees in the main with what is shown by other results that have 
 been obtained, a general correspondence between gain and loss is to 
 be observed, especially after limited periods of exposure. Upon the 
 whole, however, it must be said that the loss is usually somewhat 
 greater than the gain, and this becomes more marked as the experi- 
 ment proceeds, ending with a pronounced diminution in the total 
 carbohydrate where the exposure has been allowed to run on for a 
 period of twenty-four hours. 
 
 It may here be remarked that experimental observations upon 
 sugar-production in the fresh liver have yielded the same kind of 
 evidence regarding the relation between gain of sugar and loss of 
 glycogen. At the same time, it must be stated that in some instances 
 results have been met with which can only, with our present know- 
 ledge, be characterised as presenting an anomalous appearance. It 
 has seemed as though carbohydrate material has, upon some occasions, 
 been brought into evidence from a latent or some other state, and, 
 conversely, upon others, has disajipeared from view. 
 
 With referen'ie to the disappearance of carbohydrate, the experi- 
 ments I have conducted in search of an explanation have led to the 
 discovery of a point in connexion with the analytical procedure for 
 the determination of glycogen, which goes towards accounting for a 
 certain amount of loss. The product for analysis, it will be re- 
 membered, is first of all extracted with alcohol for the removal of 
 the sugars. The coagulated residue containing the glycogen is then 
 boiled with potash to disintegrate and dissolve the nitrogenous 
 matter, and as far as possible place it in a position to be soluble in, 
 and susceptible of removal by, alcohol. As long as glycogen is the 
 principle that has to be dealt with, no sensible amount of destruction is 
 occasioned by the boiling with potash, and, in harmony, it is noticeable 
 that in the analyses of glycogen-containing products which have 
 not been exposed to the modifying influence of ferment action the 
 
152 THE LIVER IN' RELVTIOX TO SUGAU. 
 
 i-esuUs are found to stiiid in close coufoi-mity with what might be 
 looked for. Where proiucts, hosvever, are dealt with in which 
 change through ferment action has occurred, a certain amount of 
 loss of carbohydrate is, as an ordinary occun-ence, observable in the 
 analytical results obtained. Thus it is after, and only after, ferment 
 action that the analytical results show the loss of carbohydrate. 
 
 Upon reflecting on the matter, the question presented itself to my 
 mind whether, after the ferment action, there might not be a dextrin 
 precipitated together with the glycogen by the alcohol, which failed 
 to resist destruction during the process of boiling with the 10 per 
 cent, solution of potash. I submitted the question to the test of 
 experiment in the following way, and the results obtained furnished 
 a decided answer. 
 
 For the settlement of the point, it is immaterial whether rccour.se 
 he had to the employment of starch or glycogen, on account of the 
 analogous positions held by these bodies in relation to the matter and 
 the .similai'ity of the products generated. It is also immaterial 
 which of the amylolytic ferments is made use of. In the experiments 
 performed, starch, paste, and pancreatic ferment were the materials 
 employed. 
 
 After ferment action had been allowed to piTiceed for a short time, 
 alcohol was freely added to dissolve out and separate the sugar and 
 soluble dextrins formed. The residue was collected as in the ordi- 
 nary analytical procedure, and, after being wa.shed, was divided into 
 two equal portions. Both were then mixed with the usual quantity 
 of potash. Thus far, the steps adopted presented no variation from 
 the usual coui-se. In the next step, however, one portion was boiled 
 for the accustomed time with the potash, whilst the other was simply 
 placed in contact with it in the cold. Each was then poured into 
 spirit, and the i-espective precipitates were afterwards collected and 
 t-ubjected to the inverting action of sulphuric acid. The results 
 obtained showed a conspicuously smaller amount of carbohydrate 
 where the product had been boiled with potash than where it had 
 been simply treated with potash in the cold. Seeing that starch is 
 not attacked by boiling with potash solution of the stx-ength used 
 (and the same holds good for glycogen), it is rendei'ed evident that 
 the residue remaining from the alcoholic extraction of the product 
 of ferment action contained something besides untransformed 
 
SUOAE-PRODUCTION" AFTER ALCOHOL COAGULATION. 153 
 
 starch. It may be assumed that some slightly transformed 
 material, insoluble in spirit, existed, which, unlike the starch, failed 
 to resist destruction on boiling with the 10 per cent, solution of 
 potash. The loss of carbohydrate matter appearing in the results is 
 thus to be accounted for without bringing into the question the 
 occurrence of loss from the ferment action. 
 
 Alcohol- coagulated Liver-suhsfance with Blood. 
 
 A tabular representation of the results of experiments bearing on 
 sugar-production in alcohol-coagulated liver-substance taken alone 
 was given a few pages back. I have conducted similar experiments 
 upon the same specimen of liver-substance, with the addition of blood 
 which had been dried at a temperature below that destructive of 
 ferment activity, and the results, as in the case of those obtained 
 from the admixture of blood with the fresh liver, show that a larger 
 production of sugar takes place than when the liver is dealt with 
 alone. A comparison of the table given below with that previously 
 introduced stands in support of this statement. An effect also 
 noticeable is that the product possesses a somewhat higher cupric 
 oxide reducing power. The quantity of dried liver taken was the 
 same as in the other experiments, viz. 1'5 grams, and the quantity 
 of dried blood employed was 1 gram. The sugar intrinsically 
 belonging to the blood, as shown by an examination mado, was too 
 insignificant in amount to need consideration. 
 
154 
 
 THE LIVER IN RELATION TO SUGAR. 
 
 i 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 - 3 
 -^ 
 
 i 
 
 
 
 
 
 
 
 
 
 o § 
 
 
 
 
 
 
 
 
 
 
 
 CO 
 
 
 
 t^ 
 
 ro 
 
 (M 
 
 
 CO 
 
 lo 
 
 >.-S 
 
 00 
 
 
 O 
 
 t* 
 
 
 T* 
 
 
 
 
 O 1 
 
 
 
 o 
 
 o 
 
 9 
 
 9 
 
 9 
 
 9 
 
 o 
 
 o 
 
 
 b 
 
 6 
 
 o 
 
 o 
 
 o 
 
 6 
 
 o 
 
 u 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 S 
 
 
 
 
 
 
 
 
 
 
 60 
 
 
 
 
 
 
 
 
 
 
 .3 ^*-i 
 
 
 
 
 
 
 
 
 
 
 o> o o 
 
 
 
 
 
 
 
 
 
 
 1 of th, 
 e redu 
 of the 
 that 
 ose. 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 o 
 
 
 
 iH 
 
 rH 
 
 
 
 
 
 r^ 
 
 S tS t- -^ ^ 
 
 
 
 2 
 
 O 
 
 o 
 
 _o 
 
 o 
 
 
 
 3-^ S 4i_2 
 
 
 
 
 
 
 
 
 
 
 rt o 1 3 "uj 
 ||P-| 
 
 :d 
 
 
 •^ 
 
 t^ 
 
 ao 
 
 
 o 
 
 
 -p 
 
 00 
 
 
 00 
 
 4> 
 
 t- 
 
 00 
 
 00 
 
 03 
 
 Ol 
 
 g "^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 M 
 
 
 
 
 
 
 
 
 
 
 .w 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 'g^ 
 
 
 
 
 
 
 
 
 
 
 
 i 
 
 
 
 
 
 
 
 
 
 ■r §'-- 
 
 
 .^ 
 
 „ 
 
 „ 
 
 .. 
 
 .. 
 
 J- 
 
 ^ 
 
 3 g S ^ 
 
 
 
 T? 
 
 00 
 
 T-H 
 
 (N 
 
 g 
 
 CO 
 
 CO 
 
 M _g '5, M 
 
 O 
 O 
 
 
 o 
 o 
 
 o 
 b 
 
 O 
 
 b 
 
 o 
 
 o 
 
 o 
 
 £ « 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 03 
 
 
 
 
 
 
 
 
 
 
 .d 
 
 
 
 
 
 
 
 
 
 
 -*i 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ■?^ 
 
 
 
 
 
 
 
 
 
 
 a '^ 
 
 S 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 s'a.2 
 
 t» S .d 
 
 to 
 
 
 C-l 
 
 CD 
 
 -ifl 
 
 -J< 
 
 
 ^ 
 
 -t 
 
 
 
 
 CO 
 
 o: 
 
 (M 
 
 
 
 -f 
 
 o 
 
 
 9 
 
 o 
 
 o 
 
 
 7^ 
 
 T' 
 
 T' 
 
 £"3 
 
 6 
 
 
 o 
 
 b 
 
 o 
 
 o 
 
 O 
 
 o 
 
 O 
 
 o «* 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 <D 
 
 
 
 
 
 
 
 
 
 
 .a 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 d 
 
 
 
 
 
 
 
 
 
 
 t3 
 
 
 
 
 
 
 
 
 
 
 
 
 oo 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 3 
 
 a 
 
 
 
 
 
 
 
 
 
 
 TJ 
 
 
 
 
 
 
 
 
 
 
 
 n 
 
 
 
 
 
 
 
 
 
 
 
 03 
 
 
 
 
 
 
 
 
 
 
 
 3 
 
 
 tH 
 
 si 
 
 
 
 
 
 i 
 
 1 
 
 a 
 
 
 3 
 .3 
 
 3 
 O 
 .3 
 
 ' 
 
 ^ 
 
 " 
 
 
 ■s 
 
 
 o 
 
 o 
 
 rH 
 
 N 
 
 -# 
 
 to 
 
 J^ 
 
 
 .rs 
 
 .s 
 
 m 
 
 00 
 
 
 
 
 
 
 
 g 
 
 3 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^1 
 
 1 
 
 " 
 
 
 ^ 
 
 - 
 
 ~ 
 
 ' 
 
 
 
 
 
 
 
 
 
 
 
 
 jj 
 
 I-l 
 
 
 
 
 
 
 
 
EFFECT OF ACID AND ALKALI ON FERMENT CHANGE. 155 
 
 Influence of Sodium, Garhonate and Gitric Acid on Ferment Change in 
 the Liver. 
 
 I have tried the effect produced by small quantities of sodium 
 carbonate and citric acid upon the change occurring in the alcohol- 
 coagulated liver-substance which has just been dealt vpith as a basis 
 of observation. The issue of the experiments conducted is to show 
 that the influence of the presence of sodium carbonate is in the 
 direction of diminishing the amount of transformation taking place, 
 vpithout in any marked manner affecting the cupric oxide reducing 
 power of the sugar produced ; vphilst the influence of citric acid is in 
 the direction of increasing the cupric oxide reducing power of the 
 sugar-product, rather than in that of producing any decided alteration 
 in the amount of carbohydrate transformed. 
 
 The effect of a large amount of sodium carbonate, like that of the 
 caustic alkali, is to arrest ferment change. This may be shown not 
 only by treatment of the liver after death, but likewise by the intro- 
 duction of the agent into the organ during life. In an experiment 
 upon a dog, placed and kept under the influence of ether, a lobe of 
 the liver was isolated by a ligature and excised. 20 grams of sodium 
 carbonate in 80 c.c. of water were then injected into a branch of the 
 mesenteric vein. Death occurred immediately after the completion of 
 the injection. A portion of the liver, which was shown by its black 
 colour to have been fully penetrated by the agent, was taken for ex- 
 amination, as well as the lobe that had been excised before the 
 injection was made. In each case, a certain period of time elapsed 
 between the removal of the piece to be examined and the commence- 
 ment of the analysis. The results obtained were as follows : — 
 
 Sugar per 1000, 
 expressed as glucose. 
 
 Portion of liver excised"] 
 
 before the injection [before sulplmric acid 21 '200 
 
 of the sodium carbon- I after ,, ,, 21 "200 
 
 ate J 
 
 Portion of hver removed ~| 
 
 after the injection of I before ,, ,, 1 '600 
 
 the sodium carbon- j after „ „ 2 '200 
 
 ate J 
 
 In another experiment a dog was similarly anresthetised. After 
 the isolation and removal of one lobe of the liver, 10 grams of sodium 
 
156 THE LIVEi; I\ EKI.ATION TO SUGAK. 
 
 carbonate in 40 c.c. of water were injected into the liopatic duct. 
 Ten minutes later, the animal was killed by pithing. A portion of 
 the liver that had been penetrated by the injection was, as in the 
 preceding experiment, made the subject of comparative examination 
 with the portion previou.sly removed. As a further step, portions of 
 the two specimens were placed aside and examined on the following 
 day. The analyses yielded the following i-esults : — 
 
 Sugar per 1000, 
 
 pxjjressed as glucose. 
 
 Portior of liver excised"] 
 
 before the iniection \ ■, c i i ■ • i r. ^nr. 
 
 J . I before sulphuric acid fi -iOO 
 
 of the sodium carbon 
 ate, taken a short 
 time after removal . . 
 
 after „ „ 10 '000 
 
 Portion of the samel^^f^^^ ^3 .g^^ 
 
 specimen taken on ^ ^j.^^^ ' ^^ .^^^ 
 
 the lollowing day. . . J ' ' 
 
 Portion of liver removed"] 
 
 after the injection of | ^^f^^,^ ^ ..^^ 
 
 the sodium carbonate, }-...^ '>000 
 
 and taken shortly I " ' " 
 
 afterwards J 
 
 Portion of the same "I ^^j^^^ 2 .pOO 
 
 specimen taken on ^^j^^^ ^.^^ 
 
 the loUowing day. . . J " 
 
 It will be seen that the sodium carbonate employed in these experi- 
 ments had the effect, practically, of arresting ferment action. The 
 agent thus affords a means of placing the liver in a position to escape 
 Tindergomg post-mortem change, and to permit of a representation of the 
 state belonging to life being obtained without recourse to the precau- 
 tionary measures otherwise necessary in the process of examination. 
 If reference be made to the analyses in which post-mortem change 
 was prevented by freezing (pp. 137 — 138), it will be found that a 
 strict accord is noticeable in the figures yielded by the two modes 
 of experimenting. 
 
157 
 
 THE BLOOD IN RELATION TO SUGAR. 
 
 la accordance with what is observed elsewhere throughout the 
 system, the blood is fouad to contain a certain amount of sugar. 
 Both the nature and amount of this I will proceed to consider. 
 
 Nature of Sugar present in Blood. 
 
 To determine the nature of the sugar present the proce.ss of 
 alcoholic extraction, previously described in detail (p. 61), should 
 be adopted in order to avoid the simultaneous extraction of glycogen 
 which, to a certain extent, occurs when water is employed, and which 
 would lead to the introduction of error throngli the production of 
 sugar under the process of treatment with sulphuric acid. 
 
 Observation, conducted upon blood derived_from different sources, 
 shows that the kind of sugar found in all parts of the circulation, with 
 the exception of the portal system, possesses a cupric oxide reducing 
 power that is not, as a rule, increased, and, if increased, only slightly 
 so, by boiling with sulphuric acid — a chaiacter which implies, broadly 
 speaking, the existence of glucose. This, I may state upon the 
 strength of a very large number of observations, is the kind of sugar 
 present under ordinary or natural conditions, but, as will be sub- 
 sequently shown, under certain deviations from the ordinary state, 
 as, for instance, after the administration of anassthetics, the inhala- 
 tion of cai'bonic oxide, &c., the sugar met with is usually one 
 possessing a cupric oxide reducing power more or less below that of 
 glucose. 
 
158 THE BLOOD IN KELATIOX TO SUGAK. 
 
 Aeicular glucosazone crystals from the blood of the general circuhitioQ 
 (rabbit). Magnified 400 diameters. 
 
 The blood of the portal system, however, diiSers from that of the 
 other parts of the circulation, and, at the same time, resembles, as 
 will be seen from the analyses to be given later on, the solid organs 
 and tissues of the body. Its condition was fully referred to in a pre- 
 vious part of this work, and it was there shown that it ordinarily 
 contains, not only after the ingestion of carbohydrate food, but like- 
 wise after animal food (and even in some instances the condition has 
 been observed at a time of fasting), a sugar with a lower, and it may 
 be a considerably lower, cupric oxide reducing power than that of 
 glucose. 
 
 The blood, then, excluding that belonging to the portal system, 
 contains sugar in the form, broadly speaking, of glucose, and in this 
 respect it holds a position differing, so far as my observations have 
 extended, from that existing in the other parts of the economy. 
 
 A7noimt of Sugar present in Blood. 
 Having spoken of the nature of the sugar in the blood, I will now 
 pass to the consideration of its amount. Upon this point considerable 
 
AMOUNT OF SUGAR IN BLOOD. 159 
 
 diversity exists in the statements that have been made by different 
 observers. The question of the amount of sugar naturally present in 
 the blood is one that must be regarded as possessing more than an 
 inti'insic importance on account of the meaning it may have in rela- 
 tion to considerations standing outside the simple question of fact 
 appertaining to the blood itself. It may therefore be looked upon as 
 a point upon which no doubt should be allowed to exist. The 
 enquiry requires to be approached and carried out in a scrupulously 
 guarded and careful way, but, with the adoption of proper measures, 
 experience would lead me to say, the information wanted may be 
 easily and reliably obtained. The manipulative process involves two 
 distinct steps of procedure, each of which calls for the bestowal of 
 close attention. Not only is it necessary that the method of analysis 
 should be such as to yield reliable results, but also that the blood for 
 analysis should be collected in such a manner as to afford a repre- 
 sentation of the natural state. 
 
 Analytical ijroficiency in the early days of research in relation to 
 the physiology of sugar in the animal system had not attained a 
 position to permit of satisfactory quantitative determinations being 
 made in an albuminous and coloured product like blood. Advance, 
 however, has in this, as in so many other directions, taken place, and 
 I think it may now be considered, with reference to the point iu ques- 
 tion, that a position has been reached leaving little or nothing to be 
 desired. 
 
 Aqueous ext^'action of the sugar, with the adoption of appropriate 
 measures for the separation of colouring and albuminous matters, if 
 resorted to, will yield a liquid to which the ordinary process of sugar 
 estimation may be applied, but, unless the nature of the sugar present 
 is known, the result obtained will not supply the information required 
 for the expression of the amount. In the absence of a knowledge of 
 the nature of the sugar existing, it is necessary that the process of 
 alcoholic extraction should be employed, in order that the sugar may 
 be obtained free from glycogen, and so permit, after the usual treat- 
 ment with sulphuric acid, of a trnthful expression of its amount being 
 given under the form of glucose. 
 
 When the process of extraction is carefully can-ied out, and the 
 ammoniated cupric test is employed for the subsequent estimation of 
 the sugar, the degree of accuracy attainable by experienced hands is 
 
160 ' THE BLOOD IN HEI.ATION TO SUGAi;. 
 
 such as almost to excite surprise, looking at the complex and coloured 
 nature of the original product dealt with. In support of this state- 
 ment, I may refer to the results given in au early part of this work, 
 when the subject of analytical procedure in general was under 
 consideration (p. 79). Examples arc there introduced showing the 
 close accord that is obtainable in the figures from duplicate analyses. 
 
 The conditions existing in connectiou with the collection of the 
 blood for analysis constitute au item of consideration, it may be, of 
 greater importance than the analytical procedure itself, inasmuch as 
 neglecting to give due attention to the requisite precautions may give 
 origin to greater error than would be likely to arise from a faulty 
 analysis. How rapidly sugar may be adventitiously produced in the 
 liver and lead to the presence of an abnormal amount in the blood 
 has been already shown, and in obtaining a specimen for examination 
 fallacy from such a source must be avoided by the collection being 
 made under conditions to secure a representation of the natural 
 state. 
 
 This matter, as is known, I drew attention to upwards of thirty 
 years ago. In a communication published in the Transactions of tlie 
 Royal Society for 1860, I showed that the condition which had been 
 previously taken as representative of the natural state, widely differs 
 in reality from it. With the occurrence of death, an alteration in the 
 amount of sugar present in the blood speedily ensues, but this had 
 not hitherto been recognised and taken into account. Thus, through 
 ohe post-mortem being regarded as expressive of the ante-morttm, 
 state, a false foundation existed for the physiological doctrine which 
 happened to be constructed upon what had been observed. At the 
 outset a qualitative examination was all that the resources at com- 
 mand permitted to be made, and what was considered to be the 
 characteristic reaction to be looked for from the blood of the inferior 
 cava and right side of the heart was one attended with a plentiful 
 reduction of the copper test. The amount of sugar now revealed by 
 quantitative determination as actually existing in the blood collected 
 from these parts in an ordinary way after death, depends upon the 
 extent to which it may happen to have been influenced by the post- 
 Tnortem production of sugar in the liver. A varying quantity, from 
 about that naturally belonging to the living state to one largely 
 exceeding it, may be found. 
 
AMOUNT OF SUGAR IN BLOOD. 161 
 
 The point under consideration is well illustrated by the results 
 obtained iu a recently couducted experiment, of which the following 
 are the particulars. A dog was suddenly killed by pithing, and the 
 chest immediately opened. The heart was then grasped at its base 
 with the hand, and a ligature applied so as to prevent any further 
 ingress or egress, and thus permit of the blood contained in its 
 cavities close to the moment of death being obtained for exam^luation. 
 By an incision above the ligature, the heart was excised, and the 
 blood which it contained subsequently collected. With the excision 
 of the heart, the blood present in the large vessels of the system 
 flowed into the chest. This was dipped oat, and a portion taken for 
 analysis. The following are the results that were yielded by the 
 respective specimens. 
 
 Sugar per 1009, 
 expressed as glucose. 
 
 Blood from the cavities l before siilpluiric acid 0'850 
 
 of tlie heart J after ,, 'STIJ 
 
 Blood collected from "1 before ,, 2 'ISO 
 
 tlieehest /after „ . „ 2-237 
 
 The amount of sugar found in the blood of the general circulation 
 under a natural and tranquil state of the sj'Stem presents but little 
 variation, and, as will be seen from the details to be introduced later 
 on, is less than what is met with in the solid organs and tissues. 
 From a collection of upwards of 100 observations, conducted at 
 various times over a number of years, upon the dog, cat, rabbit, 
 sheep, ox, horce and pig, the amount of sugar naturally PitESKNT in 
 
 THE BLOOD OF THE GENERAL CIKCULATION MAY BE STATED TO EANOE from 
 ABOUT 06 TO I'D, OE A LITTLE OVER I'O, PER 1000. 
 
 Most of the determinations upon which the above statement is 
 based were made with the ammoniated cupric test. In many, how- 
 ever, the gravimetric process described at p. 69 was employed. By 
 this process the copper thrown down from the Fehling's solution 
 used is collected, dissolved, and subsequently deposited by galvanic 
 action upon a platinum cylinder for weighing. Although there are 
 sufficient grounds for considering that full reliance may be placed 
 upon the information supplied by the ammoniated cupric test, it is 
 nevertheless satisfactory to have it corroborated by a diffeient kind 
 of analytical procedure ; and further so when, as illustrated by the 
 examples given at p. 80, the accuracy of both processes is confirmed 
 
1G2 THE BT.OOI) IX IJEI.ATIOX TO SUCAi;. 
 
 by tlie close accord iu the figures obtainable under tbeir application 
 to the same specimen of blood. 
 
 The blood, then, of the general circulation possesses a constitution 
 in relation to sugar presenting but little variation whilst ordinary or 
 natural conditions exist. Disturbed states of the system, however, 
 quickly occasion the presence of an increased amount, but the kidneys 
 perform an eliniinative office like that which they discharge ia the 
 case of urea. Under any increase of sugar ia the circulation, the 
 urine is immediately influenced to a proportionate extent, and the 
 escape of sugar thus occurring constitutes a provision for keeping 
 down accumulation, as is exemplified by the elimiiiatioa that is 
 observed to take place in diabetes. 
 
 In former times, when less facility existed for the quantitative de- 
 termination of the sugar of the blood, the amount corresponding with 
 what I have represented as naturally present during life was usually 
 spoken of as a "trace," the expression being founded upon the slight 
 reaction yielded by the copper test. T do not think previous attempts 
 had been made to determine what this "trace" meant, expressed in 
 figures, but in my communication contained in the Transactions of 
 the Royal Society for 1860, I gave the results I had obtained from 
 the analysis of three specimens of the blood of dogs, and stated that 
 the quantities stood respectively at 0-470, 0-730, and 0-580 per 1000. 
 These amounts, it will be seen, although obtained upwards of thirty 
 years ago, coincide closely with those yielded by the present improved 
 methods of analysis. 
 
 1 consider there ought not to be any disagreement, certainly at the 
 present time, about the amount of sugar present in blood ; and, should 
 a discordance exist, it is more likely to depend upon something con- 
 nected with the collection of the blood than upon the analytical 
 procedui-e. The figures given by some observers stand in close 
 accord with, and by other- observers even a little lower than, my 
 own. A striking want of uniformity is noticeable in the results 
 obtained by Bernard, and, whilst placing the lowest point of range 
 at 1 per 1000, he says (' Comptus Rendus,' 1876, p. 1409) that in the 
 normal state the sugar varies from 1 to 3 per lOOO. Seegen repre- 
 sents (he amount as oscillating between 1 and 2 per 1000, and 
 remai'ks that it is only exceptionally that it exceeds 2 per 1000. The 
 state of the urine suffices, I consider, to show that these ranges of 
 
PRECAUTIONS IN COLLECTING I'.LOOH. ] 63 
 
 Bernard and Seegen cannot be otberwise than foimJed upon error. 
 The larger quantities are incompatible witb the state presented by 
 healthy urine. They mean, as is rendered evident by reference to 
 the table at p. 192, representing the condition of the blcod in cases 
 of diabetes, the existence of a state that would be attended with the 
 presence of a large amount of sugar in the urine. 
 
 A contrast exists between the blood of the portal system and that 
 of the general circulation. Whilst the amount of sugar in the former 
 is in a direct manner influenced by the ingestion of carbohydrate 
 matter, no such intluencc is exerted upon the contents of the general 
 circulation. 
 
 1 have mentioned that precautions must be observed in collecting 
 the blood for examination, in order to obtain a representation of the 
 natural state. If the collection be made from an artei-y or vein 
 during life, the animal must be at the time in a state of tranquility. 
 Obstruction of the breathing, violent struggling, and the administra- 
 tion of an anaesthetic suiEce, through their disturbing effects upon 
 the system, to produce an increase of sugar in the blood. 
 
 Bernard noticed that the blood of the jugular vein of an animal 
 contai ned more sugar after muscular efforts provoked by holding the 
 nose for a short time so as to impede the respiration than it did 
 before. I also, in an experiment performed some years ago, found 
 that blood taken from a dog which had been subjected to obstruction 
 of the breathing for balf-an-hour possessed a strongly saccharine 
 character, and, in another instance, where the experiment was carried 
 on for a longer period, that the urine even had acquired a saccharine 
 impregnation sufficient to give a strong reaction with the test for 
 sugar. In like manner, after the administration of an ansesthetic, 
 the urine may be found to give even a fairly strong saccharine 
 reaction with the copper test. I took the opportunity at one time to 
 institute observations upon the urine of patients in Gay's Hospital, 
 before and alter the inhalation of chloroform, and found in every 
 instance a decided effect, in some even a strong effect, produced in 
 the direction mentioned.* 
 
 In obtaining blood from the killed animal for examination, the 
 
 * The cupric oxide reducing effect of urine after the administration of chloroform 
 is now stated to be due to gljeuronic acid, a body closely allied to and supposed to 
 be derived from dextrose, but presentrng a nither liigher state of oxidation. 
 
 M 2 
 
164 TIIK RLOOP I\ IJELATIOX TO SUGAK. 
 
 collection must be made bjfoi-e time has been allowed for its con- 
 stitution in relation to sugar to becouie altered from that appertain- 
 ing to life. 
 
 In the laboratory the conditions are under the command of the 
 experimentalist, and the method of killing employed should be one to 
 occasion death as instantaneously as possible. After the deetraction 
 of life, say by pithing, a scalpel, or pair of scissors, should be 
 instantly thrust into the chest, and the heart and large vessels freely 
 incised. The chest being then quickly opened, the required quan- 
 tity of blood should be at once dipped out or otherwise procai'ed for 
 examination. 
 
 At the slaughter-house different methods of killing are adopted. 
 The method to be chosen for securing the attainment of the object 
 in view, is one in which death is occasioned purely by hsemorrhage. 
 In the case of the sheep, the neck is pierced with a knife, and the 
 blood drained off by severance of the vessels. The first portion of 
 the blood that escapes is the proper .specimen for examination. The 
 bullock slaughtered by the Jewish method affords another in- 
 stance of killing by hEemorrhage. By a ^single incision with a long, 
 sliarp knife, all the soft structures of the neck in front of the 
 vertebral column are divided. An immense gush of blood from the 
 arteries takes place, and, as in the case of the sheep, the first portion 
 should be collected. 
 
 In the course of an inquiry I was some time ago conducting, I was 
 led to submit to examination specimens of blood from the cut bullock 
 obtained, one at the first instant of its escape, and the other a few 
 moments later. The specimens were subjected to the gravimetric 
 process of analysis, and, as will be seen from the subjoined figures, 
 a slight difference was found to exist between the two in the direc- 
 tion of a larger amount of sugar in the second portion, showing how 
 the lapse of an apparently insigiiiticant amount of time suffices to 
 brincf about an altered condition. 
 
COLLECTION OF BLOOD KOR ANALYSIS. 165 
 
 Blood of Bullock hilled hy Jewish Method, collected at the Commencement 
 and at a later Period of the Flow. Gravimetric Process of Analysis. 
 
 Sugar per 1000 parts. 
 
 ' ' ;-^ 
 
 First collection. Second collection. 
 
 Duplicate Duplicate, 
 
 analyses. Mean, analyses. Mean. 
 
 Obserration 1 j ^ /^i ^ 1 -549 | ^ ,j.^|i 1 -583 
 
 Ob-rvation2 {^''^ }o-G24 {^^-gl }o-679 
 
 After the employment of the pole-axe method of slaughterintj 
 higher iagures are ordinarily ohtained, and, concordantly, the method 
 involves the lapse of a longer time before the blood is vi^ithdrawn. 
 The animal is first felled by the blow of the axe, and through the 
 opening made a cane is then passed down the spinal canal to crush 
 the medulla oblongata and spinal marrow, a proceeding which not 
 only effectually kills outright, but puts a stop to the occurrence of 
 reflex movements. An incision is next made into the lower part of 
 the neck, and the knife passed on into the chest so as to penetrate 
 the superior vena cava, or possibly the right auricle of the heart, 
 and permit the blood to escape. Sulijoined are the results derived 
 from the analysis of four specimens obtained in this way. In con- 
 nexion with these specimens the remark is recorded that instructions 
 were given to my assistant to get the incision and collection made 
 with as little loss of time as possible after the felling of the animal. 
 In two of the observations the figures happen to about agree with 
 those obtained under the methods of slaughtering previously referred 
 to. In the other two, however, the higher kind of figures are presented. 
 
 Blood from the Bullock Slaughtered by the Pole-axe. Gravimetric 
 
 Process of Analysis. 
 
 Sugar per 1000 parts. 
 
 Duplicate analyses. Mean. 
 
 Observation 1 { 0-597 } 5!'(i 
 
 O bservatiou 2 | *? ''I^^ 1 '(ifiS 
 
 [^ U ■ Ob J J 
 
 Observations 1 1 -070 1 1 -053 
 
 Observation i j J.'^g^ |. 1 -OM 
 
166 THE liLOOI) IN KKLATION TO SUGAR. 
 
 Arterial and Venous Bluod in relation tu Sugar. 
 
 Bernard made the statement* tliat a lai'ger amount of sugar is 
 present in arterial than in venous blood, and the inference has been 
 drawn that a disappearance, occurring as a result of the functional 
 disposal of ca\'bohydrate matter in the system, takes place during the 
 transit from the arterial to the venous system. Considerable discord- 
 ance, however, is to be observed in the experimental results upon 
 which the statement has been based, and I notice an instance amongst 
 them in which an identity existed in the amount of sugar found in 
 the blood of vein and artery. According to the particulars given of 
 the experiment, a first collection of blood was made, from which the 
 figures obtained were 1'2.50 per 1000 for the venous, and 1'480 per 
 lOOO for the arterial, blood. A second collection was afterwards made, 
 when it was fonni that the figures stood at 1'560 per 1000 for both 
 the venous and arterial blood. In the instance where the largest 
 amount of difference was observed, it appears from the details fur- 
 nished that the experimental procedure adopted was as follows : 
 Blood was withdrawn from the i-ight crural vein, and immediately 
 afterwards the corresponding artery was opened and blood collected 
 from it. The results derived from the analysis of the two specimens 
 are stated to have been 0730 per 1000 for the venous, and 1'450 per 
 1000 for the arterial, blood, representing a difference of 0720 per 
 1000 between the two — a difference, that is to say, about equivalent 
 to the whole quantity of sugar which, according to my own observa- 
 tions, is found n.iturally to exist in the blood of the dog, the animal 
 upon which the experiments were conducted. 
 
 The question that is being considered is one of great importance 
 on account of the reasoning that may be based upon it. It happens 
 at the same time to be one in connexion with which fallacy may most 
 easily creep in through the difficulties attending the experimental pro- 
 cedure. Owing to the readiness and rapidity with which the blood 
 becomes charged with an increased amount of sugar, as an effect of 
 distuibod states of the system, error is certain to arise, unless the 
 most scrupulous and guarded care is exercised with regard to the 
 manner m which the collection of the respective specimens of blood 
 
 * Bernard, ' Cnmptes Rendus,' Tome Ixxxiii, No. G, p. 373 ; and ' Lemons sur le 
 Diabcte.' Paris, 1877. 
 
AKTKKIAI, AND VEX0U8 BLOOD. 167 
 
 is made. To obtain a trutbfiil representation of the ii xtural relative 
 state of arterial and venous blood, the specimens to be compared 
 must be collected absolutely at the same instant. Should the collec- 
 tion happen not to be absolutely simultaneous, the position is open for 
 the occurrence of an alteration in the amount of sugar contained in 
 the entire circulation, and this naturally would be read off as repre- 
 senting a difference in the relative amount present in the blood of the 
 artery and vein. It is further desirable that before the collection of 
 blood is made the animal should have been allowed to recover from the 
 influence of the auiBsthetic, and the effect of any struggling that may 
 have attended the operation, so that a settled state of the contents of 
 the circulatory system may have become established. 
 
 With a full realisation of the rigorous care and attention requiring 
 to be bestowed upon all the details of the enquiry, I conducted the 
 experiments which are to be found recorded in part in the ' Pro- 
 ceedings of the Royal Society ' for 1877 (vol. 26, p. 346), and in full in 
 my Croonian Lectures " On Certain Points connected with Diabetes " 
 (pp. 71 et seq.), delivered at the Eoyal College of Physicians, in 1878, 
 and published in the same year. In each of the experiments chloro- 
 form or ether was administered for the operative procedure of exposing 
 the vessels, and the vessels chosen were the carotid artery of the one 
 side, and the jugular vein of the other. After their exposure, and 
 the required isolation from the adjacent tissues, a ligature was passed 
 underneath them, and a knot tied in such a manner as to leave a 
 loose loop surrounding them of sufficient length to serve for subse- 
 quently drawing them forward without giving pain to the animal, 
 and thus without occasioning any struggling or disturbance. A 
 period of an hour and a-half or two hours was allowed to elnp-e 
 after this operative procedure for the system to recover from the 
 influeuce of the ansesthetic. At the end of this time, without the 
 einployment of any forcible restraint, and whilst the animal was 
 seated quietly on a table, the vessels were drawn forward, and blood 
 collected simultaneously from each. The process of analysis was 
 then at once commenced, and in the seven observations conducted 
 the following results were obtained. 
 
](i8 
 
 TIIK liLUUD l.N itiOI.Al'loX TO SUCUl!. 
 
 Gomparative Examinalion of Arterial ar.d Venous Blood collected 
 siin^dtaneoushj from the Dog diirimj Life. Gravimetric Process <f 
 Analysis. 
 
 Sugar per lOUO parts. 
 
 Arterial blood. Venous blood. 
 
 Duplicate 
 
 analvsps. 
 
 Mean. 
 
 Uasoi'vatioii 1 in- SI" i 
 
 01'-—^ {0-85! }•-'■ 
 
 Obse,->atio>.3.. .. [l'^^^^ }o- 
 
 0<^-""'-'^ { 0-899 }'-' 
 
 '^''^"■^'"'''^^'5 {v081 }l' 
 
 Observation 6 { J .|^^ }l- 
 
 Observation 7 1 1 • 1 "1 1 M 
 
 Duplicate 
 analyses. 
 r -808 
 10 -788 
 
 j 0-896 I 
 
 10-86.3 /" 
 
 /0-918 1 
 
 rO-859 \ 
 
 10-873 j" 
 
 jl-102 I 
 
 j 1 -240 1 
 
 1 lost i ^ 
 
 Meau. 
 I- -798 
 
 On casting the eye through the above list, it will be noticed that a 
 clo.se conformity exi.sts in the figures for the corresponding specimens 
 of arterial and venous blood. In some, the difference presents an 
 excess on the side of the arterial blood ; in others, on that of the 
 venous. In each case, it does not amount to more than may be 
 legitimately considered as falling within the limits of variation aris- 
 ing from the analysis, for it is not claimed that absolute accuracy is 
 attainable. It must be borne in mind, with reference to the matter, 
 that about 20 grams of blood were taken for analysis, and that the 
 figures represent parts per 1000, so that what may be an exceedingly 
 slight error in the analysis becomes magnified about fifty times in the 
 multiplication employed for the expression of the result. A differ- 
 ence, for instance, of one-tenth of a milligram in the actual analysis 
 would become a difference of 0005 in the result expi-essed. The 
 duplicate analyses give a trustworthy character to the evidence, 
 beyond what it would otherwise possess, and the closeness noticeable 
 in the counterpart results affords strong testimony of the precision 
 attainable by the analytical process employed. In observation 6 one 
 of the results for the venous blood is missing, owing to an accidental 
 
AinEi:iAL .VXD VENOUS 15L00D. 169 
 
 loss of some of the precipitated suboxide having occuri-ed in the per- 
 formance of the analysis. In observations 5, 6, and 7 the amount of 
 sugar encountered stands higher than what is found to exist under 
 ordinary circumstances. This, it may be considered, is attributable 
 to the effect of the ansesthetio. If blood be withdrawn whilst tho 
 animal is actually under the influence of the ansesthetic it is possible 
 that upwards of 2 parts per 1000 may be found, and, from the 
 results referred to, it would appear that even after the lapse of an 
 hour and a half or two hours the sugar may not have fallen to its 
 standard amount. 
 
 Looking now at the results, taken altogether, we find that the mean 
 amount of sugar, given by calculation from the mean figures 
 furnished by tho seven observations, stands at 0'995 per 1000 for the 
 arterial blood, and 0997 per 1000 for the venous. The difference 
 between the two thus amounts to 0-002 per 1000, and it happens, as 
 is seen, that the excess, such as it is, falls on the side of the venous 
 blood. 
 
 By another mode of experimenting that suggested itself to me as 
 open for employment, blood was obtained from artery and vein as 
 expeditiously as possible after death, so as to anticipate the altered 
 state induced by the post-mortem production of sugar. Four such 
 experiments were performed upon dogs. The animal was in each 
 case pithed, and, instantly afterwards, a scalpel was drawn across the 
 artery and vein determined upon, without any attempt being made to 
 isolate them. The blood that simultaneously flowed from the respec- 
 tive vessels was collected in capsules. The danger to be guarded 
 against in tbe experiment was from the possibility that the flow 
 mifht not be precisely even after the first gush, and that, in carrying 
 on the collection, a little blood might be included which had under- 
 gone a slight degree of post-mortem modification. Attention was 
 therefore given that the collection was not carried further than the 
 withdrawal of the quantity absolutely required for the piurpose of 
 examination. 
 
 In observation I, the collection was made from the jugular vein of 
 one side of the neck, and the carotid artery of the other. In conse- 
 quence of the experience gained in this experiment the crui'al arteiy 
 was substituted for the carotid in the other three. Its more super- 
 ficial position rendered it more accessible for division. The jugular 
 
170 THE IlLOOD IN liELATION TO SUGAK. 
 
 was still retained as Hie vessel for yielding tbe venous Llood. Since 
 the blood througbout the ai'terial system possesses at a given moment 
 the same constitution, it is obvious that any artery that is most con- 
 veniently situated for the performance of the experiment may be 
 taken. In connection with observation 4, it is recorded that a little 
 difficulty occurred in collecting the arterial blood, through its flowing 
 slovs'ly from the divided vessel, and that the last portion was dark in 
 colour. In this condition it may possibly have just commenced to be 
 influenced by the ■post-mortem influx of sugar from the liver. 
 
 Comparative Examinntion of Arterial and Venous Blood, collected 
 simultaneously, instantly after Death. Gravimetric Process nf Analysis. 
 
 Sugar per 1000 parts. 
 
 Arterial blood. Venous blood. 
 
 Duplicate Duplicate. 
 
 aniil\ PCS. Mean, analyses. Mean. 
 
 Observation! {o'ms } 0-926 {"iggy 1 0-900 
 
 Observation 2 {^i^jJJ jo-79.'; J^™^ |o-r92 
 
 Observations (o'sl? lo'S-tS i^'-lH 1 0-850 
 
 Observation 4 {^-.^l^ jo-g.! [HH }o-797 
 
 Tbe results derived from these four observations present, it is 
 noticeable, a less even character than those belonging to the previous 
 set. The mean amount of sugar given for the arterial blood is 847 
 per 1000 ; and for the venous 0-834 per 1000. The difference stands 
 at O'OIS per 1000, the higher figures being furnished by the arterial 
 blood. 
 
 Placing now the eleven observations together we get 0-941 per 
 1000 as the expression of the mean amount of sugar found in the 
 arterial blood, and 0'938 per 1000 in the venous. It thus appears, for 
 the whole of the observations, that the sugar in the arterial blood 
 exceeded to the extent of 003 per 1000 that in the venous. 
 
 The conclusion, I consider, may be drawn from the foregoing ex- 
 periments that no material difi'erence exists in the amount of sugar 
 present in arterial and venous blood. As a corollary, it follows that 
 
BLOOD AFTER WITIIIUiAWAL. 171 
 
 no support is given to the view that carbohydrate matter in the form 
 of sugar is allowed io reach the general circulation, for conveyance 
 as a functional operation to the systemic capillaries to be disposed of 
 by the tissues. 
 
 Professor Seegen, who widely differs from me upon other points, is, 
 I find, in accord with me upon the one which has just been con- 
 sidered. In the French translation, which is before me, of his 
 recent work on animal glycogenesis,* he says " II resulte de la que, 
 contrairement a I'opinion de CI. Bernard et de Chauveau et d'accord 
 avec les recherches de Pavy et autres, il n'y a pas de difference appre- 
 ciable entre le sang arteriel et le sang veineux quant a la proportion 
 de Sucre qu'ils renferraent." 
 
 Blood after Wilhdraival, in Belalioii to Sugar. 
 
 I liave now finished what I have to say upon the question of the 
 disappearance of sugar- from circulating blood, and I will proceed to 
 consider the question of its disajipearance from blood after with- 
 drawal from the system. 
 
 In correspondence with the statement that was made with regard 
 to cii'culating blood, it was further asserted by Bcrnardf that a dis- 
 appearance of sugar takes place in drawn blood, sufficient in extent 
 and rapidity to furnish additional support to the theory of carbo- 
 hydrate disposal to which attention has above been given. 
 
 At quite an early period of my investigations, and long before the 
 matter which is being discussed was broached, I gave attention to 
 the subject of the disappearance of sugar from drawn blood, and, from 
 what I observed, I mentioned that a disappearance occurred, which 
 seemingly ran concurrently with the changes that lead on to decom- 
 position. I further mentioned that I had observed, with blood con- 
 taining much sugar, an acid reaction produced, which I suggested was 
 probably attributable to the formation of lactic acid. I also noticed 
 that in the presence of fibrin and corpuscles the disappearance took 
 place with greater rapidity than when serum alone was dealt with. 
 
 When the assertions of Bernard to which I have been directing 
 
 • ' La Glycogenie animale,' by Professor J. Seegen. Translated by Dr. Halm : 
 Paris, 1890, p. 100. 
 
 t Bernard, ' Coraptes Kendus,' 19th Juin, 1876, p. 1-106. 
 
172 THE BLOOD IN RELATION TO SUGAR. 
 
 atteuti'on were marie, I not only conducted the experiments I have 
 referred to in relation to circulating blood, but also carried my investi- 
 gations to drawn blood ; and, in the prosecution of the enquiry, I was 
 now aided by the methods of quantitative analysis which were not at 
 my command when my original observations weie undertaken. The 
 experiments are to he found recorded in the ' Proceedings of the 
 Royal Society ' for June, 1877 (Vol. XXVJ, p. 346), and April, 18/9 
 (Vol. XXVIII, p. 520). 
 
 In giving a representation of what was found, I will first cite the 
 particulars of five observations in which the blood was allowed to 
 stand for moderate lengths of time at the ordinary temperature. The 
 observations, it will be noticed, were conducted at different periods 
 of the year, and thus under the existence of somewhat different 
 temperatures. 
 
 Bluod after Standing, compared loith Bhiod taken Immediatehj. 
 Gravimetric Process of Analysis. 
 
 Sugar per 1000 parts. Percentage 
 Mean of two loss of 
 
 analyses. Bugar. 
 
 January 29th. 
 
 Taken immediately 0'786 — 
 
 „ after 1 hour -7.39 6 '0 
 
 April 25th. 
 
 Taken immediately '700 — 
 
 „ after 1 hour -670 4 -3 
 
 May 18th. 
 
 Taken immediately '76(3 — 
 
 „ after 1 hour 0-7.51 2-0 
 
 „ after 23 hours -285 62 '8 
 
 May 2nh. 
 
 Taken immediately 786 — 
 
 „ after 1 hour Q- 728 7 -4 
 
 „ after 24 hours 0-302 61 '6 
 
 May 26th. 
 
 Taken immediately 921 — 
 
 „ after If hours 793 13 9 
 
 In another set of experiments blood was allowed to stand for 
 longer periods of time. In these the sugar was determined by the 
 
P.[>001) AKTEl; WITHDRAWAL. 173 
 
 ammoniated cupriu test, and not by tlie gravimetric process, winch is 
 oidy adapted for the examination of blood in a fresh state. With 
 the occurrence of decomposition, the ammonia generated interferes 
 with the deposition of the cuprous oxide, and thus in the case of the 
 gravimetric process gives rise to a vitiated result. In the case, on 
 the other hand, of the ammoniated cupric test, which in its principle 
 of operation depends upon the solvent action upon the cuprous oxide 
 exerted by ammonia, decomposition produces no vitiating effect and 
 accordingly stands as no barrier to its employment. By this method 
 of analysis, therefore, the examination can be conducted at any 
 period, no matter whether the blood be in a fresh or a decomposed 
 state. In these experiments the. product for titration was obtained 
 by the sulphate of soda method (vide page 59) resorted to for the 
 gravimetric process, that is by boiling with sulphate of soda to 
 coagulate albumiuous and colouring matters, filtering, thoroughly 
 washing the coagulum, and bringing the liquid to a knowQ volume. 
 The following examples may be selected and given to represent tlie 
 character of the results obtained. 
 
 Blood after prolonged Standing at the ordinary Temperature compared 
 
 with Blood taken Immediately. Sugar determined by the Ainmo- 
 niated Cupric Test. 
 
 Percentage 
 
 Sugar per loss of 
 
 1000 parts. sugar. 
 Blood of bullock — 
 
 Day of withdrawal 0-775 — 
 
 1 day afterwards 0-334 5fi-9 
 
 2 days , -253 67 -4, 
 
 5 „ „ 0-231 70-2 
 
 Blood of bullock — 
 
 Day of withdrawal 1 - 111 — 
 
 1 day afterwards 717 35 "5 
 
 2 days ,, 0-5-15 510 
 
 3 „ , 0-294 73-5 
 
1/4 THE BLOOLi ]X REI.ATIOX TO SUGAR. 
 
 Blood icilh added Glucose siihjected to prolonged Standing at the 
 ordinary Temperature. 
 
 Pcreenlage 
 
 Sugar per loss of 
 
 1000 parts. sugar. 
 Blood of bullock — ■ 
 
 In fres-h state 776 — 
 
 After addition of sugar 3 '636 — 
 
 On the following day 2 -811 22 7 
 
 On the third day -296 91 9 
 
 On the sixth day 0-228 92 7 
 
 The original blood, to which no 
 sugar had been added, ex- 
 amined on the sixth day ■223 70 
 
 In other experiments the blood was exposed to a temperature about 
 equal to that of the body, and at the same time was subjected to the 
 influence of currents of difFerent gases. In order that the results 
 might be expressed by larger figures, and any effect produced tlius be 
 rendered more visible, some glucose was added at the commencement 
 of the experiment. 
 
 Blood with added Sugar exposed to a moderately elevated Temperature 
 and to the Influence of Currents of different Gases. 
 
 Percentage 
 Sugar per loss of 
 
 1000 parts. sugar. 
 
 Sheep's blood in a fresh state, with added 
 sugar — 
 
 Taken at once 1 '850 — 
 
 After standing 7 hours at a 
 
 slightly raised temperature. . . 1*550 16 '2 
 
 After the passage of oxygen for 
 7 hours at a slightly raised 
 
 temperature 1-52d 17 6 
 
 After the passage of carbon di- 
 oxide for 7 hours at a slightly 
 
 raised temperature 1 "525 17 6 
 
 After the passage of hydrogen 
 for 7 hours at a slightly raised 
 temperature 1"570 151 
 
BLOOD AFTEU WITHDRAWAL. 175 
 
 Percentage 
 Sugar per loss of 
 
 1000 parts. sugar. 
 
 Sheep's blood in a fresli state, with added 
 sugar — 
 
 Taken at once 1 'GSi — 
 
 After standing 2i hours at 3S' C. 1 • 4:9 10 7 
 
 After the passage of oxygen for 
 
 2i hours at 38° C 1-285 21-4 
 
 After the passage of carbon di- 
 oxide for 2i hours at 38° C. . . 1 -lOO 32 7 
 
 Sheep's blood in a fresh stite, with added 
 sugar — 
 
 Taken at once 1 • 607 — 
 
 After standing 7 hours at 38" C. 1 342 19. 5 
 
 After the passage of oxygen for 
 
 7 hours at 38' C 0-992 40-0 
 
 After the passage of carbon di- 
 oxide for 7 hoiu-s at 38° C. . . . 1 '042 37 ■ 5 
 
 Sheep's blood in a fresh state, with added 
 sugar — 
 
 Taken at once 1 • 475 — 
 
 After standing for 6| hours at 
 
 38°C 1-324 10-2 
 
 After the passage of oxygen for 
 
 6^ hours at 38° C 1134 23-2 
 
 After the passage of carbon di- 
 oxide for 6k hours at 38° C. . . 1 - 209 18 
 
 Sheep's blood in a fresh state, witli added 
 augar — 
 
 Taken atonce 1-775 — 
 
 After standing 6i hours at 38° C. 1-567 11-7 
 
 After the passage of oxygen for 
 
 6i hours at 38° C 1475 16 9 
 
 After the passage of carbon di- 
 oxide for 64 hours at 38° C. . . 1 "492 15-9 
 
 Sheep's bloofl in a decomposed state, with 
 added sugar — 
 
 Taken at once 1 -324 — 
 
 After standing 6 hours at 38° C. 0-667 49 -S 
 
 After the passage of oxygen for 
 
 fi hours at 38° C OGOG 542 
 
 After the passage of carbon di- 
 oxide for 6 hours at 38° C -65 1 50 -6 
 
176 THE liLOOD IX KKLATIOX TO SUCAIi. 
 
 Looked at iu their entirety, tliese exjierimeutal results sliovv that 
 an arivancing disappearance of sngar takes place iu drawn blood. 
 Beyond this nothing definite can be said, and nothing I consider is 
 deducible to warrant the conclusion that wliat is noticed to occur 
 can be interpreted as having any physiological bearing. With an 
 unstable body like sugar existing in contact with a complex organic 
 product like blood, it is nothing more than might be expected that 
 such disappearance as is observed should occur, and no need exists to 
 briiig into the question the operation of living action. 
 
 In the experiments where blood was subjected to the influence of 
 the transmission of currents of different gases, it is noticeable that a 
 greater disappearance of sugar occurred in the specimens that were 
 so treated than in the counterpart specimens which were simply 
 allowed to remain at rest. It is not, however, discoverable that 
 more effect was definitely produced by one gas than by another, and 
 it may be considered probable that the greater loss attendmg the 
 employment of the gas was due to the physical efftct of the molecular 
 movement occurring. 
 
 The largest loss is observable where the blood employed was in a 
 decomposed state. This is only in accord with what might be looked 
 for. 
 
 A point to be noted in connection with the ob.servations is that the 
 blood invariably retained a certain amount of cupric oxide reducing 
 power. In no instance, even where evidence of advanced decomposi- 
 tion existed, did the reducing power of the product fall below from 
 0'2 to 03 per 1009, expressed as glucose. What, in short, occurred 
 was that the reducing power fell until the point named was reached, 
 after which no further change ensued, however long the blood was 
 kept. From this, the conclusion suggests itself that the blood con- 
 tiins a certain amount of something besides the sngar possessing 
 c ipric oxide reducing power, which, unlike sugar, resists the de- 
 structive influence of the decomposing matter around. If this is the 
 c.ise it follows that the sugar actually existing in the blood is less by 
 G"2 to 03 per 1000 than what has been represented under the 
 assimption that the cupric oxide reducing effect observed is due 
 solely to sugar. i 
 
 Let.ine^s Theory regardlTig Glyrolysia in Blood. — From the results of 
 obscrv itions on the disappearance of sugar in drawn blood, Le])ine 
 
ALLEGED GLYCOLYSIS IN BLOOD. 1*77 
 
 has founded an argument in which he contends for the occurrence of 
 glycolytic ferment action in the blood during life. Much discussion 
 has recently taken place upon this matter. The view is of a nature 
 to be likely to attract attention, seeing that it aims at accounting for 
 the destruction of the sugar assumed under the glycogenic doctrine 
 to reach the general circulation — a necessary provision for obviating 
 the existence of diabetes as a general state. Weighty objections have 
 been raised by various authorities to the experiments and conclusions 
 of Lepine, looked at upon their own merits. There is, however, the 
 further point, which has not been considered by others, that if, as 
 follows from what has been adduced in this work, sugar does not 
 reach the general circulation as the glycogenic doctrine implies, the 
 raison d'etre of a glycolytic ferment in the blood does not exist, and 
 the question about glycolysis in the blood is devoid of the jihysiological 
 significance that would otherwise belorg to it. 
 
178 
 
 THE URINE IN RELATION TO SUGAR. 
 
 Presence of Suijur in Healthy Urine. 
 
 I have incideutally referred to tlie elimiuation of sugar that takes 
 place from the blood through the medium of the urine. I will now 
 proceed to fully consider the relationship existing between blood and 
 urine with regard to sugar. Whilst it is universally admitted that 
 the blood contains a certain amount of sugar, the urine is in ordinary 
 language spoken of as free from it. It is true that on testing a 
 specimen of normal urine with Fehling's solution — the sugar test in 
 common use — no reaction is obtained. This must not, however, be 
 taken as proving the complete absence of sugar. There is a limit to 
 the sensitiveness of every test, and in the case of sugar the amount 
 present may be too small for the test to reveal it. Moreover, with 
 urine, other materials are present which exert an influence upon the 
 test contributing in some measure to mask the indication of sugar. 
 Observation shows that an amount of sugar distinctly recognisable in 
 a pure aqueous solution may not be recognisable when existing in 
 urine. In water there is nothing to interfere with the deposition, and 
 consequently the ready perception, of any suboxide that may be 
 formed. In urine, on the other hand, the ammonia developed by the 
 action of the potash of the test upon the nitrogenous matter present 
 may suifice to hold in solution the suboxide produced when only 
 small in amount. In may thus happen that no precipitate at all is 
 produced, when in reality a certain a.mount of reduction has taken 
 place. The only actual effect under the circumstances to be perceived 
 is a certain extent of fading of colour, which it may be is so slight as 
 to be barely appreciable, from the diminution of the oxide of copper 
 by its conversion into suboxide. It is of course only where the 
 quantity of sugar present is minute that it is liable to be concealed in 
 this way. Where the amount is large the suboxide produced is 
 beyond the capacity of the ammonia generated to dissolve it, and it 
 then falls as the well-known precipitate belonging to the action of the 
 test. 
 
SUGAR IN HEALTHY URINE. 179 
 
 Although it may thus be found that no reaction is perceptible on 
 testing healthy urine with the copper solution, the presence of sugar 
 is nevertheless susceptible of being demonstrated by appropriate 
 means. Briicke, it is known, some years back devised a process for 
 the separation of sugar by throwing it down in combination with 
 oxide of lead. The process is an eminently satisfactory one, and by 
 its means sugar, to however minute an extent it may be present, can 
 be extracted and placed in a position to be easy of recognition. By 
 operating upon a sufficiently large quantity of urine, an amount of 
 sugar is obtainable which admits not only of recognition but likewise 
 of quantitative determination. I will here give the main points of 
 the process, and for full details upon the whole subject may refer to 
 an article written by me " On the Recognition of Sugar in Healthy 
 Urine," which was published in the ' Guy's Hospital Reports ' for 
 1876. 
 
 The urine is first treated with neutral followed by basic acetate of 
 lead. The effect of this is to lead to the precipitation of the uric 
 acid, sulphuric acid, phosphoric acid, hydrochloric acid, and, doubt- 
 less, some other constituents of the urine, as lead compounds, the 
 sugar remaining in solution. Filtration is performed, and the filtrate 
 is treated with ammonia, and a further quantity of acetate of lead, 
 unless a large excess of it has been in the first place added. The 
 sugar falls in the precipitate now produced, through the formation of 
 a definite, insoluble compound of sugar and oxide of lead. The pre- 
 cipitate is then collected, and, in order to secure the complete removal 
 of ammonia, washed until the washings no longer produce any effect 
 upon reddened )itmus paper. The next step is the liberation of the 
 sugar from the compound existing in the washed precipitate. This 
 may be effected by the agency of hydrochloric, sulphuric, or oxalic 
 acid, but a somewhat coloured product is the result, and it has been 
 suggested that the possibility may exist of tlie formation of sugar by 
 the action of the acid upon some other constituent of the urine carried 
 down with the lead precipitate. A more colourless, and therefore 
 better, product is yielded by sulphuretted hydrogen. Although its 
 application involves the occupation of considerable time, it constitutes 
 decidedly the preferable agent for employment. The washed lead 
 precipitate is subjected to the action of a stream of the gas until the 
 sugar compound is completely broken up, which may be assumed to 
 
 N 2 
 
180 THE URINE IN KELATION TO SUGAR. 
 
 have occurred when the product has acquired an absolutely uniform 
 black colour throughout. Filtration is next performed, and the 
 excess of sulphuretted hydrogen expelled by heat. The liquid is 
 then reduced to a small bulk, either over the water-bath or in tne 
 vacuum of an air-pump. 
 
 The product thus obtained is in a strongly acid state, and presents 
 a considerable amount of colour. Neutralisation with carbonate of 
 soda leads to the gradual deposition of a coloured substance, which 
 should be removed by filtration. If any evaporation by heat is sub- 
 sequently resorted to, the liquid should first be made slightly acid with 
 acetic acid to guard against any destruction of sugar through the 
 influence of alkalinity. To place the product in a more suitable 
 position for the application of chemical tests, colour should be E.till 
 further removed by the agency of animal charcoal, the charcoal em- 
 ployed having been well purified from lime. It must, however, be 
 remembered that animal charcoal uot only absorbs colouring matter 
 but tends also to take up and hold sugar with some tenacity. 
 Thorough washing is therefore required in order to fully recover the 
 sagar. 
 
 As stated in the article (" Recognition of Sugar in Healthy 
 Urine ") to which I have referred, I applied the process that has 
 just been described in outline, and satisfied myself of the truth of the 
 assertion that in the product yielded sugar is to be found. I spared 
 no pains to obtain adequate quantities of the isolated material to operate 
 upon. The process of extraction was carried on from day to day for 
 a considerable time, as fresh portions of urine were obtained, and 
 altogether, in the course of the numerous observations undertaken, 
 fully 100 litres passed under examination, in quantities of two or 
 three litres at a time. Attention was given to secure that all the 
 urine was derived from healthy persons, and the precaution was 
 further taken of examining each collected portion with Fehliug's 
 solution, and rejecting any that gave the slightest indication of a 
 reaction. 
 
 Subjected to examination by the application of the undermentioned 
 tests, the product behaved in the following manner: — 
 
 Boiling with a solution of potash was attended with the production 
 of the deep brown colour known to occur in the presence of glucose. 
 
 The addition of a few drops of nitrate of bismuth, and then of a 
 
SUGAR IX HEALTHY URINE. 181 
 
 solution of potash or soda (Bottger's test) gave a white precipitate, 
 which became black on boiling-, in accord with the effect produced by 
 sugar. 
 
 Boiling with Fehling's solution gave rise to the production of an 
 immediate and copious precipitate of the reduced oxide of copper. 
 For thi.s, however, the complete removal of the ammonia used in the 
 preparation of the product was necessary. With incomplete removal, 
 the neat and decided reaction otherwise observed was replaced by 
 decoloration and delay of precipitation till after somewhat prolonged 
 boiling. It is to be remarked also that where lime, derived from the 
 employment of animal charcoal which had been imperfectly freed 
 from this principle, was permitted to be present, an interference with 
 the proper reaction of the test was occasioned by the semi-gelatinous 
 precipitate it produced. 
 
 The tests which have been referred to can only be said, strictly 
 speaking, to afford presumptive evidence of the existence of sugar. 
 The occurrence of fermentation, however, manifested by the produc- 
 tion of alcohol and carbonic acid gas, may be regarded as supplying 
 absolute proof of its presence. On exposing the product derived from 
 the urine to the influence of yeast, I expected, looking at the statements 
 that had been made and the reactions afforded by the other tests, to 
 meet with decided evidence of the occurrence of fermentation, and 
 was surprised to find that it did not ensue. Not only had fermenta- 
 tion been described as taking place, but estimations of the amount of 
 sugar present had been made through the carbonic acid gas evolved. 
 That the fault was not on the part of the yeast I employed was shown 
 by the brisk fermentation which occurred when a portion of it was 
 placed in an aqueous solution of grape sugar and exposed to the suit- 
 able temperature. At a loss to account for the negative results that 
 I obtained, I tried the effect of exjjerimenting with urine to which 
 sugar had been purposely added. Again the result was of a negative 
 character. It thus became presumable that there was something 
 connected with the state of the product which checked the activity 
 of the ferment. I noticed t^at a strongly acid condition existed, and 
 it occurred to me to ascertain whether this might exert an arresting 
 influence on ferment action. I thus was led to neutralise the prodiict 
 with carbonate of soda, and I then found that fermentation actively 
 proceeded. Through not having recognised, therefore, the necessity 
 
182 THE URINE IN KELATION TO SUGAB. 
 
 of giving attention to this point, I failed in my first attempts to 
 obtain fermentation. The circumstances observed stand, it is to be 
 remarked, in accord with the statement of Pasteur, that acidity 
 opposes vphilst alkalinity favours the occurrence of fermentation. 
 
 In addition to the evidence already brought forward founded upon 
 methods of testing with which we have been long familiar, further 
 evidence is now adducible, derived from the application of other 
 methods which have been recently discovered to constitute valuable 
 tests for sugar. 
 
 Phenylhydrazine, already frequently referred to in this work, is 
 an agent which forms crystalline compounds — osazones — with the 
 various sugars. A convenient method of applying the test to healthy 
 urine is the following : — The sugar is thrown down in the manner I 
 have already had occasion to describe (p. 179), by the hydrated oxide 
 of lead. The precipitate containing the lead compound is washed 
 with water (it is not here necessary as for the application of the 
 copper test to wash to such an extent as to get rid of the whole of the 
 ammonia), dissolved in acetic acid to liberate the sugar, and the solu- 
 tion treated with sulphuric acid for the precipitation and separation 
 of the lead. After filtration, the liquid, which already contains the 
 acetic acid wanted, is treated with phenylhydrazine in the requisite 
 proportion, heated on the water-bath for about an hour, and after- 
 wards set aside to cool. In the course of some hours osazone 
 crystals separate out. Subjoined are photo-engravings from micro- 
 photographs of osazones from different kinds of urine. 
 
SUGAl! is HKALTHY UKINE. 
 
 183 
 
 Osazoi c crystals from the sugar of healthy human uriuo. 
 Magnified 400 diameters. 
 
184 
 
 THE t'lilNK IX KKLATION TO SUGAE. 
 
 Osazone crystals from the sugar of horse's urine. Magnified 400 diameters. 
 
SUGAR IX IIKALTIIV URIXE. 
 
 1S5 
 
 t Osuzouc crysials Iroui the sugar of llii' unae of llio dog fed on auimal food. 
 Mafruified 400 diameters. 
 
 Osazone crystals from the sugar of rabbit's urine. Magnified 400 diameters. 
 The globular masses consist of free phenyl-hydrazine. 
 
186 THE UltlNE IN RELATION TO SUGAR. 
 
 Benzoyl chloride constitutes anotiier recently introduced, test 
 which possesses the character of extreme delicacy. The reaction is 
 founded upon the formation of an insoluble compound with sugar. 
 When shaken up with healthy urine it gives a white granular pre- 
 cipitate resembling that yielded with a solution of glucose. 
 
 The accumulation of evidence which has been presented may be 
 considered, I take it, to absolutely set the question that has been 
 discussed at rest, and leave no room for doubt about healthy urine 
 containing a certain amount of sugar. That such should be the case 
 is, indeed, only in accord with what might be looked for, in view of 
 the fact, about which there is no dispute, that a certain amount of 
 sugar is present in the blood. 
 
 Amount of Sugar present in Healthy Urine. 
 Satisfied upon the point that sugar was to be regarded as a con- 
 stituent of normal urine, I subsequently sought to obtain information 
 with regard to its amount. At the time of my first giving attention 
 to the subject the ammoniated cupric test had not been introduced 
 and I employed the gravimetric process which has been previously 
 referred to in these pages. Under the circumstances existing, this 
 process is open to the risk that the full extent of cnpric oxide reduc- 
 tion may not be represented by the suboxide collected, in con- 
 sequence of a little ammonia having escaped removal in the washing 
 of the precipitate containing the lead oxide compound. With the 
 ammoniated cupric test, it happens that no such risk of misrepre- 
 sentation of cupric oxide reduction is incurred, and it altogether 
 affords a far more ready and advantageous method for application, 
 Moreover, we are here placed upon different ground, for the test 
 admits of being directly applied to the urine itself, thus dispensing 
 with the previous separation of the sugar. The uric acid possessing, 
 as it is known to do, cupric oxide reducing power, requires to be first 
 removed, and this may be effected by precipitation with the neutral 
 followed by the basic acetate of lead. Without the employment of 
 the latter some of the uric acid fails to be precipitated, and may be 
 subsequently recognised by crystallisation, contrary to what is the 
 case when the basic as well as the neutral acetate has been employed. 
 The sugar passes with the filtrate, from which the surplus lead is 
 removed l/y sulphuric acid cautiously added till it no longer pre- 
 
URINARY AND BLOOD SUGAR PROPORTIONATE. 187 
 
 cipitates. After filtration potash is used to render alkaline, and 
 titration is then performed with the test solution. If the cupric 
 oxide reduction found to occur be read off as pi-oduced entirely by 
 sugar, the amount of this principle ordinarily existing in healthy 
 urine may be said to stand at about 0'5 or a little over per 1000. 
 
 Relation of the Sugar of the Urine to that of the Blood. 
 
 Under the presumption that a negatiTO behaviour with the ordinary 
 mode of testing was indicative of an absence of sugar, Bernard con- 
 tended that up to a certain point sugar might exist in the blood with- 
 out passing off with the urine. 
 
 In support of this, he stated that if half a gram of grape sugar 
 per kilo, of body-weight were injected into the jugular vein of a 
 rabbit none appeared in the urine, whilst if a gram per kilo, were 
 employed a certain amount was to be found. He went furthei', and 
 asserted that in the dog the blood might contain 2'4'0 per 1000 of 
 sugar without any being discoverable in the urine, whilst if it con- 
 tained 2'60 per 1000, sugar was to be met with. The mean, or 2"50 
 per 1000, he spoke of as representing the amount that could be 
 tolerated in the blood without passing off with the urine. With refer- 
 ence to this last statement, it may be safely assumed that his experi- 
 mental basis was at fault, for, as will be seen later on, 2o0 per 1000 
 of sugar in the blood constitutes a condition that is attended with the 
 escape of a notable amount of sugar with the ui'ine. In the case of 
 the injection of the half gram and the 1 gram of sugar per kilo, into 
 tbe circulation of the rabbit, the difference observable resolves itself 
 into a question of whether the amount reaching the urine sufficed to 
 be revealed by the sensitiveness of the test or not. 
 
 In reality, up to a certain point, sugar may exist in the urine 
 without being indicated by the ordinary mode of testing, and the 
 difference between nrine which does, and that which does not, give a 
 reaction is simply a difference of degree as regards amount, instead 
 of, as it presents the appearance of being, a difference of kind. 
 
 In Bernai'd's experiments sugar was injected into the circulation 
 and the urine subsequently examined with the ordinai-y copper test, 
 a test which, as I have pointed out, has a limit of sensitiveness that 
 permits a certain small amount of sugar to escape being revealed. 
 With the urine of the rabbit especially, which is often much loaded 
 
188 THE URINE IN RELATION TO SUGAR. 
 
 •with solid matter, tlie development of ammonia in the application of 
 the test may be such as to conceal a considerable amount of sugar. 
 This I have ascertained by comparing the reaction with that given 
 by the ammoniated cupric test. As much as 5, C, or 7 per 1000, or 
 even more, may be shown to be present by the ammoniated cupric 
 test, without anything but an obscure reaction being given with 
 Fehling's solution. 
 
 I have undertaken a set of experiments with the view of penetrat- 
 ing further into the matter under consideration. Sugar was injected 
 into the circulation, and the sugar present in the blood determined, 
 in some instances immediately, and in others at the end of different 
 periods. Where the mine was obtainable, quantitative determina- 
 tions of the sugar which it contained were also made. The animals 
 experimented upon were rabbits of about 2 kilos, weight. From 15 
 to 20 c.c. of honey solution, containing definite quantities of glucose 
 (determined by titration), were in each case injected into the jugular 
 vein. In order that the normal state might as nearly as possible 
 prevail, the employment of an anesthetic was purposely avoided. 
 Steps were taken to secure that the animal remained tranquil during 
 the operative procedure ujaon the vein, and, as a matter of fact, but 
 little notice seemed to be taken by it of what was done. For obtain- 
 ing the blood, the animal was killed by pithing, the chest opened, and 
 the right heart incised, the whole being done as rapidly as possible 
 in order to preclude the influence oi post-mortem change. The results 
 of the experiments stood as follows : — 
 
 Injection of 1 (/ram of Glucose per kilo, of Body Weir/ht. 
 
 Rabbit I— Sugar per 1000, 
 
 Killed at once ; no urine obtainable. expressed as glucose. 
 r^ -T 1-1 1 f before sulphuric acid ,. 5 '050 
 
 Cardiac blood i ,t r . r^nr, 
 
 |_ alter ,, ,, 5 000 
 
 Rabbit II— 
 
 Killed at once ; no urine obtainable. 
 
 /-IT Li J r before sulphuric acid 5 ' 5.55 
 
 Cardiac blood I ^j^^_. ^' ^^ ^_ 5.2^3 
 
 Rabbit Ill- 
 Killed 30 minutes after the injection ; 
 no urine obtainable. 
 
 „ ,. ,, , r before sulphuric acid 2 '450 
 
 Cardiac blood I ^fj^^ '„ , 2-703 
 
URINARY AND BLOOD SUGAR PKOPORTIONATE. 189 
 
 Sugar per 1000, 
 Rabbit IV — expressed as glucose. 
 
 Killed 1 hour after tlie injection. 
 
 <-i J' Li 1 f before sulphuric acid 1 "460 
 
 Cardiac blood I _^f^^^ '„ , 1-666 
 
 Urine obtained J before sulphuric acid 55 "160 
 
 after death . \ after „ „ 55 "160 
 
 Rabbit V— 
 
 Eilled li hours after the injection. 
 
 n T t,i 1 f before sulphuric acid 1 '243 
 
 Cardiac blood i r. ^ t .roo 
 
 1_ alter „ „ 1533 
 
 Urine obtained / before sulphuric acid . 11 '370 
 
 after death . t after „ , 21-150 
 
 Injection of 0-5 gram of Glucose per kilo, of Body Weight. 
 
 Rabbit VI— Sugar per 1000, 
 
 Killed at once; no urine obtainable. expressed as glucose. 
 
 /-I 1- ui J r before sidphuric acid 2-380 
 
 Cardiac blood in o. 
 
 lafter „ „ 2-548 
 
 Rabbit VII— 
 
 Killed 30 minutes after the injection ; 
 no urine obtainable. 
 
 Cardiac blood | ^f,"'" «^^P''""« ^"'"^ 1-573 
 
 1_ after „ „ 1 -573 
 
 Rabbit VIII— 
 
 Killed 1 hour after the injection. 
 
 Cardiac blood | ^f "''^ ^ulpl^u'-ic acid 1 -390 
 
 (_ after „ , 1 370 
 
 Urine obtained J before sulphuric acid 11 -370 
 
 after death . t after „ 17-8GO 
 
 These experiments fail to support the proposition of Bernard re- 
 garding a tolerating capacity of the system for a certain amount of 
 sugar. The re.sults obtained were such as might naturally be looked 
 for with the introduction of a diffusible substance like sugar into the 
 circulation. Where 1 gram per kilo, was injected, and the blood was 
 examined immediately, the amounts discoverable are observed to 
 stand in close conformity. From the amounts found immediately 
 after the injection, both of the gram and the half gram quantities, a 
 steady fall is traceable in those met with at subsequent periods. At 
 the end, however, of an hour and a half the fall had not reached the 
 point representative of the normal condition. The urine, where it 
 was obtainable, showed the presence, even after the injection of the 
 half gram per kilo., of a considerable amount of sugai', and in one of 
 
190 THE URINE IN RELATION TO SUGAR. 
 
 the experiments after the injection of the one gram the quantity 
 amounted to 55 per 1000. 
 
 It must not escape notice, in experiments of the nature under con- 
 sideration, that the state of the bladder, as regards fullness or 
 emptiness at the time of the injection, will form an important factor 
 in determining the character of the result obtained, by influencing 
 the extent to which the urine secreted after the injection is diluted 
 by that previously existing. 
 
 A point deserving a passing comment is that in some of the 
 instances a sugar with a lower ciipric oxide reducing power than 
 that of glucose was present, notwith.standing glucose was the form 
 of sugar injected. 
 
 In another series of experiments, Isevulose derived from the 
 recently devised process of manufacture was injected into the circu- 
 lation in place of the glucose (mixture of dextrose and laevulose) of 
 which honey consists. 1 gram to the kilo, of body weight was the 
 quantity used, and the steps of operative and analytical procedure 
 were precisely the same as in the experiments recorded above. 
 
 Injection of 1 gram of Lcevulose per kilo, of Body Weight. 
 
 Eabbit I— Sugar per 1000, 
 
 Killed at once. expressed as glucose. 
 
 „ ,. , , , r before sulpliuric acid 4387 
 
 Cardiac Hood | ^^^.^^^^ '_ ^_ g.^^^ 
 
 tlrine obtained / before sulphuric acid 3571 
 
 after death . \ after ,, „ 6'2.50 
 
 Eabbit II— 
 
 Killed 30 minutes after the injection. 
 
 „ ,. , , , r before sulphuric acid 2'523 
 
 Cardiac blood I ^^.^^^ ,, „ 2-577 
 
 Urine obtained J before sulphuric acid 97'402 
 
 after death, t after „ „ 71-091 
 
 Rabbit Ill- 
 Killed 1 hour after the injection. 
 
 „ J. , , , f before sulphuric acid 1-893 
 
 Cardiac blood -i r. i onn 
 
 { alter ,, „ 1 800 
 
 Urine obtained /before sulphuric acid 37037 
 
 after death . 1 after „ „ 35-333 
 
 Eabbit IV— 
 
 Killed IJ hours after the injection. 
 
 rt js- ui 1 r before sulphuric acid 1-603 
 
 Cardiac blood j^jj^^. i^_ _ ^.g,^ 
 
 Urine obtained /before sulphuric acid 80-303 
 
 after death . \ after „ , 25-900 
 
URINARY AND BLOOD SUGAR PROPORTIONATE. 191 
 
 On looking through these results and comparing them witli those 
 belonging to the preceding series in which 1 gram per kilo, of 
 glucose from honey was injected, it is noticeable that no significant 
 diiference in the amount of sugar found in the blood exists between 
 the two. It fortunately happened that urine was procurable from 
 each of the rabbits after death. In that obtained from rabbit II, the 
 proportion of sugar was strikingly large, whilst with rabbits III and 
 IV a notable amount was also found. The conspicuous point of 
 difference observable from the preceding series is in the fall in the 
 amount of sugar occasioned by boiling with sulphuric acid. This 
 effect of the treatment with acid is only in harmony with the known 
 property of Isevulose in becoming more easily destroyed or lost by the 
 action of heat and acids than dextrose. From the urine of rabbit I, 
 in which only the sugnr naturally belonging to the healthy state was 
 present, the figures obtained after the treatment with sulphuric acid 
 are higher than those yielded before the treatment. The inverted 
 condenser, it may be remai-ked, and not the autoclave, was employed 
 in the case of all the urines. 
 
 As the outcome of all that has preceded, not only may it be said 
 that sugar normally exists in the ux*ine, but further that it is present 
 in pi'oportion to the amount contained in the blood ; and this holds 
 good for the slight fluctuations occurring under ordinary conditions 
 as well as for the larger amounts occurring in connection with 
 diabetes. 
 
 In illustration of this last assertion, I may give the results of 
 some observations which I conducted some years ago upon persons 
 suffering from diabetes, and which were recorded in the Croonian 
 Lectures, " On certain points connected with Diabetes," 1878, p. 80. 
 Blood obtained by cupping was analysed, and the urine passed during 
 the corresponding twenty-four hours' period was collected, measured, 
 and examined. 
 
 In the appended table the particulars are arranged so as to show 
 the salient points belonging to each observation. Case I was that of 
 a patient suffering from a severe form of diabetes, and subsisting at 
 the time upon a diet of ordinary mixed food. II and III were also 
 severe cases, and in these, observations were conducted when the 
 patients were upon an ordinary mixed diet, and again when the sugar 
 to be eliminated had been diminished by the exclusion of starchy and 
 
192 THE UIUNE IN RELATION TO SUGAE. 
 
 sacchai'ino matter from the food. Case IV was one of a milder type, 
 and the sugar passed under a partially restricted diet was less than 
 that passed under the restricted diet in the other cases. 
 
 Nothing could show more clearly than these results that the 
 amount of siigar appearing in the urine stands in proportion to the 
 amount existing in the blood. The urine in reality constitutes the 
 channel of exit for the sugar which is abnormally present in diabetes, 
 and in this way affords the natural provision for keeping down the 
 amount within the system. Such being what is noticeable with 
 reference to the sugar belonging to diabetes, it would indeed be 
 strange if a different princii^le prevailed with reference to that 
 belonging to health, and if, with a diffusible substance like sugar, the 
 contention of Bernard held good that a hard and fast line existed 
 between escai:)e and non-escape with the urine. The fact, indeed, is 
 that a small iimount of sugar, as has been shown, exists in healthy 
 urine, in harmony with the small amount existing in healthy 
 blood. As the amount rises in the blood so it rises in the urine, 
 without any absolutely sharp line of demarcation existing between the 
 normal and abnormal states. The transition, in fact, from health to 
 disease, instead of being abrupt, takes place by gradations of an 
 insensible nature. 
 
URINARY AND BLOOD SUGAR PROPORTIONATE. 
 
 193 
 
 
 '/.-; 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 PH^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 r;-' 
 
 o ^ 
 
 « lO vo 
 
 O O 00 « 1 
 
 
 
 CO -1< <M 
 
 l^ CO Ttl -J. 1 
 
 
 
 I> >0 CD 
 
 
 
 
 
 
 
 
 . • 
 
 w 
 
 3J '"^ 
 
 O "5 5-1 
 
 4). (i-i rt ^ 1 
 
 
 
 
 
 
 
 
 t. Cl 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 == 3 
 
 
 
 
 
 
 r/} -^ 
 
 
 
 
 
 
 
 
 
 
 
 
 11 
 
 r-( 00 -f< 
 
 OJ C3 rH CD 
 
 
 O O ^3 
 
 m -i" rt I- 
 
 
 
 C5 Ti* f-H 
 
 CO <o 00 ^ 
 
 
 - o 
 
 O 05 to 
 
 03 ^ -f CO 
 
 
 a^o 
 
 
 
 
 
 
 
 
 
 
 
 li' 
 
 g 
 
 " 
 
 : ' " 
 
 
 t. o 
 
 to 
 
 
 
 
 rf .a 
 
 o o « 
 
 t~ 00 rH (35 1 
 
 
 = -f 
 
 ^ 0? i-O 
 
 ^ lO -^ 1> 1 
 
 
 W ^5 
 
 in CO ^ 
 
 
 00 cq 
 
 fl 
 
 
 !>. CD »l 
 
 Srt 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 to £> 
 
 C 
 
 
 CD CO CO -fl 
 
 
 11 
 
 c 
 
 II 
 
 O O O O 
 
 
 
 
 
 
 02 SB 
 
 
 
 
 
 
 ^ 
 
 
 
 
 
 
 P. oi 
 
 
 
 
 
 
 tH 
 
 
 
 
 
 -^ 3 
 
 
 
 
 
 
 ■"^ 2 
 
 or 
 
 -? t- 
 
 Oi c 
 
 ^ Ol 
 
 
 d ""* 
 
 c 
 
 t^ o 
 
 t^ I^ 
 
 O 'O 
 
 
 s ■* 
 
 
 ■* -* 
 
 05 -t 
 
 !>. OD 
 
 
 
 CD 
 
 CD CO 
 
 1.0 (^ 
 
 
 
 cl^'' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 '^ -3 
 
 
 
 
 
 
 
 
 'C3 -— 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 T-l 
 
 
 
 
 
 
 
 Case II. 
 
 Mixed diet. 
 Eestricted ( 
 
 Case III. 
 cpd diet 
 
 1 
 
 Case IV. 
 
 Partially resti 
 Partially restr 
 
 
 
 ^ 
 
 si 
 
 g« 
 
 
 
 
 
 
 
 
 
 in 
 
 00 C-1 
 
 __. .£ 
 
 '^■9 
 
 
 
 
 K>, 
 
 *J o 
 
 Oi M 
 
 
 
 5 
 
 
 00 ? 
 
 .BM 
 
 
 
 J 
 
 
 a.2 
 
 ^ S 3 
 
 
 
 
 S a 
 
 3 3 
 
 S^ 
 
 
 
 
 1-= 1-5 
 
 1-5 hs 
 
194 
 
 MUSCLE IN RELATION TO SUGAR. 
 
 In accord with what is noticeable elsewhere throughout the system, 
 muscle contains a certain amount of sugar. I have made a large 
 number of observations upon the sugar belonging to it, and will here 
 furnish a representation of the information which has been obtained. 
 
 Mammalian Aimnals. —The following digest gives the main points 
 of information derived from 115 determinations of muscle-sugar in 
 tlie dog, rabbit, cat, sheep, horse, and pig. 
 
 Nature of Sugar. 
 As regards the nature of the sugar met with, it is to be stated that 
 the cupric oxide reducing power belonging to it stood, in the great 
 majority of instances, below that of glucose. The ordinary range of 
 reducing power was from about 45 or 50 to about 80, as compared 
 with that of glucose at 100. The average was found to be about 65. 
 
 Osazone crystals from the sugar of muscle (bullock). 
 Magnified 400 diameters. 
 
NATURE OF SUOxAR IN MUSCLK. 
 
 195 
 
 Osazoue cnstuls from the sugar of leg muscle (dog). Magnified 400 diameters. 
 
196 
 
 MllSf'LE IN RELATION TO SUGAB. 
 
 Osazone crystals from tlie sugar of cardiac muscle (dog). Magnified 400 iliameters. 
 
 Amount of Sugar. 
 
 The amount of sugar, estimated in the form of glucose, stood in 
 the largest number of instances at from 2 to 4 per 1000, In no 
 instance was the quantity found to be less than 1 per 1000. Rarely 
 was it observed to exceed 5 or 6 per 1000. Upon one occasion, how- 
 ever, as much as 9 per 1000 was found. The instance falls in the 
 series of analyses given a little further on of muscular tissue taken 
 
AMOUNT OF SUGAR IN MUSCLE. 197 
 
 from different parts of a dog, and applies to the muscle of the hind 
 leg. The accompanying glycogen figures stood, it was likewise 
 noticeable, unusually high. Another large amount that I find re- 
 corded was yielded by the muscular tissue of the diaplu'agm of a dog, 
 the figures for which stood at 3'800 per 1000 before treatment with 
 sulphuric acid, and 7'100 per 1000 afterwards. In this case, as in 
 the other, muscular tissue taken from different parts was examined. 
 The analytical figures for the other parts were of an ordinaiy char- 
 acter. The amount of the accompanying glycogen was below the 
 usual. 
 
 To ascertain whether an ordinarily conducted examination fur- 
 nishes a correct representation of the amount of muscle-sugar existing 
 during life, a piece of muscle was in several instances removed 
 quickly after death, and placed in a freezing mixture, whilst another 
 piece was taken in an ordinary way. No difference of a definite 
 nature was encountered. The following detailed account of an 
 observation may be giren : — 
 
 Cupric oxide 
 reducing power of the 
 Sugar per 1000, sugar present in 
 
 expressed as relation to that of 
 
 Rabbit — glucose. glucose at 100. 
 
 Muscle of fore-leg — 
 
 -r. 1- f before sulphuric acid . . 1 '747 "1 
 
 Frozen portion I ^j^^^ \, „ .. 2-730 | 
 
 Unfrozen por- f before „ „ . . 1 "983 
 
 tion 1 after „ „ .. 2-567 
 
 Muscle of hind-leg — 
 
 Tj ,. /before „ „ .. 2-130 "I-q 
 
 Frozen portion I ^jj^_. j' - ..3-640 F^ 
 
 Unfrozen por- J before ,, ,, •• 2-427 loi- 
 
 tion 1 after „ „ .. 3-640 /°' 
 
 Amount of Sugar hi Muscular Tissue derived from different parts. 
 
 The muscular tissue taken from different parts of the same animal 
 was sometimes found to present considerable variation in relation to 
 the amount of sugar present. The following is aa example in 
 illustration : — 
 
 }77 
 
198 MUSCLE IN KELATION TO SUGAK. 
 
 Cupric oxide 
 reducing power of the 
 Sugar per 1000, sugar present in 
 
 oxjiressed as relation to that of 
 
 glucose. glucose at 100. 
 
 Dog- 
 Muscle of tongue. . . . { !;[^;^ ^"Ipliunc aeul 2 -458 J g^ 
 
 ,. , /before „ „ 1-662 1^, 
 
 diaphragm I ^fj^^. >_ j_ 2-259 f^^ 
 
 , ^ r before „ „ 2-855 1,., 
 
 '■™-t •••• latter „ „ 4-700 J''^ 
 
 , . , , /before „ „ 6-502 "1 ^.„ 
 
 lund-leg.. I^ftp^ „ „ 9-292 | ''' 
 
 Nothing was deducible from tlie observations pointing to the 
 existence of any specific diifereuce associated witb a difference in the 
 kind of animal. 
 
 Question of the Influence of Food. 
 
 No effect was traceable to food, e.xcept that in a group of instances 
 ■where sugar was administered in conjunction with other food a rather 
 higher range of figures was presented. 
 
 Non-Mammalian Anivi.als : — I have given a summai-ised, instead of 
 a detailed, representation of the observations conducted upon the 
 mammalian animal, on account of the large number to be dealt with. 
 Those upon other animals, being comparatively few, may be given 
 in full. Two points are noticeable in connexion with them. The 
 amount of sugar is in general less, and its cupric oxide reducing 
 power, especially in the case of the crustacean animal, lower — in 
 some instances indeed conspicuou.sly lower — than in the mammal. 
 
 Cupric oxide 
 reducing power of the 
 Sugar per 1000, sugar present in 
 
 expressed as relation to that of 
 
 glucose. glucose at ICO. 
 
 Fuwl- 
 
 Muscleofbreast|'^f/"™^"'P'""-''^'''^"l---- If^ 1 
 
 [_ Jiitcr ,, „ . . . 1 -i *o40 J 
 
 '• ^ Latter „ „ .. .. 1-930 J 
 
 { 
 
 Grouxc — 
 
 ■ before „ „ • . . . 1 130 
 ^aft«r „ ,, 2-730 
 
 Muscle of breast ■{ 
 
MUSCLE OF VARIOUS ANIMALS. 
 
 1!*0 
 
 Tortoise- 
 
 Muscle I ^t''"' s"lpl'"'-i= «"^' 
 
 Tortoise — 
 
 Muscle . 
 Frog— 
 
 Muscle . 
 Frog- 
 
 Muscle . 
 Salmon — 
 
 Muscle . 
 Cod— 
 
 J before 
 |_ after 
 
 J before 
 t after 
 
 / before 
 \ after 
 
 J before 
 \ after 
 
 Muscle I^f"'''' 
 
 l_ after 
 
 Turbot— 
 
 ^-'^ {'j!:r 
 
 Mackerel — 
 
 f before 
 ' ■ \ after 
 
 Muscle 
 Plaice — 
 
 •««■ 1 /"before 
 
 ^"'•^l^ 1 after 
 
 Fel— 
 
 n r 1 f before 
 
 Muscle ■{ p, 
 
 l_ after 
 
 Muscle / before 
 
 (another portion) \ after 
 
 Lobster — 
 
 Muscle of tail. . ■{ J, 
 
 t after 
 
 , f before 
 " ^'1*^ {after 
 
 J before 
 \ after 
 
 Lobster — 
 
 Muscle of tail. . 
 
 , f before 
 claw J. „, 
 
 \^ alter 
 
 Lobstei — 
 
 Muscle of tail. . 
 
 claw 
 Crab— 
 
 Muscle of claw 
 Crab— 
 
 Muscle of claw 
 
 / before 
 t after 
 f before 
 \ after 
 
 f before 
 \ after 
 
 / before 
 \ aftei' 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 C'upric oxide 
 
 reducing power of th 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 . . 1 -220 
 .. 1-810 
 
 \g7 
 
 . . 1 -272 
 .. 2-254 
 
 J56 
 
 .. 0-970 
 . . 3 -030 
 
 |32 
 
 .. 0-975 
 . . 2 -330 
 
 |42 
 
 . . -530 
 .. 2-300 
 
 |23 
 
 . . -830 
 .. 2-170 
 
 |38 
 
 . . -830 
 . . 1 -460 
 
 |57 
 
 .. 2-469 
 . . 4 -502 
 
 |55 
 
 .. 2-453 
 . . 3 -240 
 
 |75 
 
 . . -800 
 . . 2 -030 
 
 |39 
 
 . . -700 
 .. 1-810 
 
 |38 
 
 . . 1 -037 
 . . 1 -720 
 
 jeo 
 
 .. 0-780 
 . . 2 -730 
 
 |28 
 
 .. 0-620 
 .. 1-660 
 
 |37 
 
 .. i-7f;o 
 
 . . 2 -090 
 
 |83 
 
 .. 0-230 
 . . -743 
 
 |31 
 
 . . -270 
 .. 0-624 
 
 |43 
 
 .. 1-500 
 . . 1 -500 
 
 jioo 
 
 . . 1 -482 
 . . 2 -392 
 
 |62 
 
200 
 
 THE SPLEEN IN RELATION TO SUGAR. 
 Representative examples from a collectiou of twenty observations. 
 
 Cupric oxide 
 reducing power of tlie 
 Su^ar per 1000, sugar present in 
 
 expressed as relation to that of 
 
 Spleen of horse 
 Spleen of sheep 
 Spleen of dog . . 
 Spleen of dog . . 
 Spleen of dog . . 
 
 /before sulphuric- acid, 
 t after „ „ . 
 
 ... 1 
 . .. 1- 
 
 /before 
 
 \ after „ „ . 
 
 ... 1- 
 
 / before „ „ . 
 t after „ „ . 
 
 ... 1- 
 
 ... 1- 
 
 f before „ „ . 
 t after „ „ . 
 /before „ „ . 
 laitcr „ „ . 
 
 ... 2- 
 ... 3 
 
 glucose. 
 
 634 
 
 984 
 77 
 587 
 827 
 032 
 777 
 342 
 8111 
 
 glucose at 100. 
 
 Osazone crystals from the sugar of the spleen (horse). 
 Magnified 400 diameters. 
 
201 
 
 THE KIDNEY IN RELATION TO SUGAR. 
 
 Repi-esentative examples from a collection of fifteen observations. 
 
 Cupric oxide 
 
 Kidney of liorse. . 
 Kidney of liorse. . 
 Kidney of dog . . , 
 Kidney of dog . . . 
 Kidney of sheep. . 
 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 reducing power of tbe 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 J before sulpliuric acid. 
 \ after „ „ . 
 
 . . 1 -572 
 .. 2-575 
 
 jei 
 
 J before ,, ,, . 
 L after „ „ . 
 
 . . -896 
 .. 1-132 
 
 |79 
 
 /before ,, „ . 
 t after 
 
 .. 1-685 
 . . 2 -229 
 
 |76 
 
 /before „ ,, . 
 I after „ „ . 
 
 . . 1 -12.3 
 .. 1-765 
 
 |64 
 
 /before „ „ . 
 \ after „ „ . 
 
 . .. 0-960 
 .. 1-380 
 
 |70 
 
 Osazonc crystals from the sugar 'of the kidney (lior.scJ. Slagnified 400 diameters. 
 
202 
 
 THE PANCREAS IN RELATION TO SUGAR. 
 Represeutative examples from a colleetiou of eigliteen observatious. 
 
 Pancreas of liorso 
 
 {I 
 
 before sulplnirie acid 
 ■t'tcr 
 
 Pancreas of sliecp < ,., 
 
 Pancreas of 
 
 slieep -j 
 
 before 
 after 
 
 ■n c , f before 
 
 Pancreas of dog.. I ^fjg^. 
 
 ■D c J f before 
 
 Pancreas ot dog. . -i ,. 
 
 Sugar per lOOO, 
 expressed as 
 glucose. 
 1-463 
 2-688 
 -7.31 
 1-388 
 0-712 
 0-725 
 0-812 
 1-433 
 2-314 
 3-343 
 
 C'upric oxide 
 
 reducing power of the 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 1 54 
 
 }- 
 
 \m 
 
 7 
 69 
 
 }' 
 
 THE LUNG IN RELATION TO SUGAR. 
 
 Four observations. 
 
 Lungs of 
 Lungs of 
 
 Lungs of 
 
 Lungs of 
 pups 
 
 dog.. 
 
 dog . . 
 ftetal 
 
 f before i 
 \ after 
 J before 
 ■ "[after 
 
 {before 
 after 
 / before 
 \ after 
 
 Liljihuric acid 
 
 Sugar per 1000, 
 expressed as 
 glucose. 
 1 -545 
 2-183 
 3-186 
 4-870 
 0-917 
 1-406 
 1-631 
 1 -725 
 
 Cupric oxide 
 
 reducing power of the 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 l71 
 
LUNG IN KELATION TO SUGAK. 
 
 203 
 
 Osazone crystals from the augax' of the hiug (tlog). Magnified 400 diameters. 
 
204 
 
 THE BRAIN IN RELATION TO SUGAR. 
 
 Representative examples from a collection of six observations. 
 
 Tj • ( 1 r before sulphuric acid 
 
 Brain of dog -( .r^._ "^ 
 
 Brain of dog. 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 \ after 
 
 {before 
 after 
 
 -D ■ r J r before 
 
 ^'•'""°f''°g t after 
 
 780 
 500 
 318 
 705 
 720 
 216 
 
 Cupric oxide 
 
 reducing power of tlie 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 \o2 
 
 THE PLACENTA AND FCETUS IN RELATION TO SUGAR. 
 
 Four observations. 
 
 x)i i I J r before sulnhui-ic acid 
 
 Placenta of dog.. I ^f^^j. i _^ 
 
 Placenta of rabbit ■{ f.. . " 
 
 Foetuses removed"] 
 
 from the uterus [before „ 
 
 of a recently fafter ,, 
 
 killed rabbit J 
 
 Placenta and early J before ,, 
 
 foetuses ofrabbit\ after „ 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 461 
 438 
 263 
 285 
 
 845 
 699 
 
 411 
 
 043 
 
 Cupric oxide 
 
 reducing power of the 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 >■ glucose 
 1 55 
 
 }" 
 
 1 69 
 
205 
 
 ORGANS OF GENERATION OF FISH AND CRUSTACEA 
 IN RELATION TO SUGAR. 
 
 
 
 
 
 Cupric oxide 
 reducing power of the 
 
 Cod — 
 
 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 sugar present in 
 relation to that of 
 glucose at 100. 
 
 Spermatic 
 
 , / before sulphuric acid. 
 ''' "\ after „ „ . 
 
 .. 0-430 
 . . 1 -960 
 
 |22 
 
 Ovary . . . 
 
 
 J before „ „ . 
 t after „ „ . 
 
 . . -630 
 . . 1 -950 
 
 |32 
 
 
 
 Mackerel — 
 
 
 
 
 
 Spermatic 
 
 r before ,, „ . 
 "'•g'^n after „ „ . 
 
 . . 2 -300 
 . . 3 -680 
 
 \g2 
 
 Ovary . . . 
 
 
 / before „ „ , . 
 t after „ „ .. 
 
 . . 1 '530 
 . . 4 -090 
 
 |37 
 
 Lobster — 
 
 
 
 
 
 Ovary . . . 
 
 
 f before „ „ . 
 latter „ „ .. 
 
 .. 3-440 
 . . 7 -380 
 
 |47 
 
 Lobster — 
 
 
 
 
 
 Ovary . . . 
 
 
 / before „ „ , , 
 t after „ „ .. 
 
 . . 3 -600 
 . . 3 -600 
 
 |ioo 
 
 Ova attached t 
 tail 
 
 r before „ „ . . 
 \ after „ „ .. 
 
 . . 1 -430 
 .. 2-570 
 
 |55 
 
 Crab- 
 
 
 
 
 
 Ovary . . . 
 
 
 f before „ „ . . 
 \ after , 
 
 . . 2 -600 
 .. 4-300 
 
 jeo 
 
 Crab- 
 
 
 
 
 
 Spermatic 
 
 f before ,, ,, ■ . 
 o'-g'^n after I „ .. 
 
 . . 2 -020 
 . . 4 -750 
 
 |42 
 
206 
 
 THE EGG IN RELATION TO SUGAR. 
 
 The egg agrees with other animal products in containing a certain 
 amount of sugar. My observations have been conducted upon the 
 egg of the domestic fowl, and I have carried my enquiry to the con- 
 dition existing during the progress of incubation. 
 
 Taking the entire egg and including the shell in the initial weight, 
 the following figures show the amount and nature of the sugar found 
 in three analyses : — 
 
 Fresli egg — 
 
 , J before sulphurie acid. 
 
 t after 
 
 2 r before ,, „ . 
 L after ,, ,, . 
 „ J before „ „ . 
 tatter 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 . .. 1-962 
 
 . . . 1 -962 
 
 . . . 2 -560 
 
 . . . 2 -560 
 
 . . . 2 -554 
 
 . . . 2 -554 
 
 Cupric oxide 
 
 reducing power of the 
 
 .sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 ^ glucose 
 V glucose 
 > glucose 
 
 An examination of the white and yolk separately gave the sub- 
 joined results. The egg taken weighed, including the shell, 63-13 
 grams. The white obtained from it weighed 37-06 gTams, and the 
 yolk 18-75 grams. The .sugar figures respectively yielded stood as 
 follows : — 
 
 White . 
 Yolk . . 
 
 
 Cupric oxide 
 reducing power of the 
 
 Sugar per 1000, 
 expressed as 
 
 sugar present in 
 relation to that of 
 
 glucose. 
 
 glucose at 100. 
 
 f before sulphuric acid ... . 3-418 
 l after „ , 3-262 
 
 j- glucose 
 
 r before „ „ -789 
 
 I after „ , 0-832 
 
 }95 
 
 Nearly mature ova, taken from the ovary and therefore compre- 
 hending only the yolk, gave, on examination, the following figures : — 
 
NATURE AND AMOUNT OF SUGAR. 
 
 207 
 
 Nearly mature ova 1 , » , , • • , 
 
 , , •" » 11 berore sulphuric acicl. 
 
 taken trom the f „f^. 
 ovary J ,, ,, . 
 
 Sugar per 1000, 
 
 expressed as 
 
 glucose. 
 
 . . . -sor, 
 
 ... -808 
 
 Cuprie oxide 
 
 reducing power of the 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 It thus appears that the kind of sugar met with is, in both white 
 and yolk, shown to be practically glucose, and that the white contains 
 a far larger amount than the yolk. For the entire egg the quantity 
 stands at from about 2 to about 25 per 1000. 
 
 The character of the osazone derivable from the sugar of the egg 
 confirms what has just been stated regarding the form of sugar 
 present. Subjoined is a photo-engraving from a micro-photograph 
 of the crystals obtained from an aqueous extract of the white of egg 
 treated with phenylhydrazine. They constitute typical crystals of 
 
 lucosazone. 
 
 Osazone crystals from the sugar of the egg. ilaguilicd -100 diameters. 
 The effect of incubation was studied through the employment of an 
 
208 
 
 THE EGO IN RELATION TO SUOAF. 
 
 incubator. Pains were taken to procure fertile eggs, but many of 
 them, nevertheless, failed to undergo any development. In others 
 development proceeded up to a certain point and then stopped. It 
 further unfortunately happened, in connexion with a batch, that just 
 before the completion of the full term of incubation the temperature 
 was permitted to fall below the proper point, which led to several 
 nearly mature chicks being found dead within the shell. It was 
 found in all cases that, under exposure in the incubator, a loss of 
 weight steadily occurred, amounting, at the end of the twenty-one 
 days term of incubation, to something considerable. In one instance 
 it was noticed to have reached to as much as over 20 grams. To 
 secure a uniform basis of comparison, the initial weight of the egg 
 was taken in making the calculation. If calculated in relation to the 
 diminished weight existing, higher projjortionate figures would be 
 presented, giving a semblance of the occurrence of an increase in the 
 amount of sugar where no increase had actually taken place, or con- 
 cealing a fall where such in reality had occurred. 
 
 When the egg was removed from the incubator, the shell was 
 broken and a careful examination made, to see if any development 
 had occurred. Of the eggs which were found not to have undergone 
 development, several were submitted to analysis, as well as those 
 which had done so. The results obtained ran as follows : — 
 
 Period wlien taken 
 and condition. 
 
 8tli day- 
 Live chick 
 
 9tli day- 
 Live oliick 
 
 11th day- 
 Live chick 
 
 J before sulphuric acid . . 
 ' \ after „ „ .. 
 
 / before 
 1 after 
 
 Sugar per 1000, 
 
 expressed aa 
 
 glucose. 
 
 0-918 
 0-970 
 
 / before 
 \ after 
 
 12tli day- 
 Live feathered / before 
 chick \ after 
 
 14tU day — 
 
 Live feathered /before 
 
 cliick \ after 
 
 Small dead / before 
 
 chick X after 
 
 0-59-t 
 0-59i 
 
 0-733 
 0-789 
 
 0-637 
 0-859 
 
 0-618 
 0-690 
 0-421 
 0-427 
 
 Cupric oxide 
 
 reducing power of the 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 95 
 
 glucose. 
 
 74 
 
 90 
 
INFLUENCE OF INCUBATION. 
 
 209 
 
 Period when taken 
 
 Sugar per 1,000, 
 
 aud condition. 
 
 expressed as 
 
 16th day— 
 
 glucose. 
 
 Live feathered /before 
 chick \ after 
 
 sulphuric acid. ... • 578 
 
 „ .... 0-662 
 
 Evidence of ~1 
 
 
 some ineipi- 1 
 
 
 ent develop- (^before 
 
 „ .... 1-191 
 
 inent, but no [ after 
 
 „ .... 1-253 
 
 distinct em- | 
 
 
 bryo noticed J 
 
 
 19th day- 
 
 
 sman dead f before 
 chick \ after 
 
 „ 0-514 
 
 „ -562 
 
 21st day— 
 
 
 Fair-sized dead "l 
 
 
 chick of (before 
 
 „ 0-391 
 
 Cupric oxide 
 
 reducing power of the 
 
 sugar present in 
 
 relation to that of 
 
 glucose at 100. 
 
 about the 
 10th day 
 
 20th dav— 
 
 Nearly full- 
 sized dead 
 chick 
 
 before 
 after 
 
 21st day— 
 
 Nearly full- I , . 
 
 • "^1 11 berorc 
 
 sized dead > „, 
 
 chick J'^f'" 
 
 21st dav— 
 
 Nearly full- 1 . , 
 
 sized dead ^f^''^ 
 
 chick j ""•-''• 
 
 8th day- 
 Undeveloped 
 
 lOth day- 
 Undeveloped . . 
 
 Ifith day— 
 
 Undcveloiicd .. 
 
 17th day — 
 
 No appearance 
 of develop- 
 ment 
 19th day- 
 No appearance 
 of develop- 
 ment 
 2l8t day — 
 Undeveloped , 
 
 {before 
 after 
 
 r before 
 L after 
 
 r before 
 \ after 
 
 I before 
 I after 
 
 I before 
 f after 
 
 r before 
 \ after 
 
 0-744 
 l-OoS 
 
 0-539 
 0'68S 
 
 0-591 
 0-!S27 
 
 2-4.85 
 2-528 
 
 2-797 
 2-811 
 
 2-450 
 2-206 
 
 0-543 
 0-543 
 
 -656 
 0-035 
 
 1-014 
 1 -218 
 
 99 
 
 glucose, 
 
 glucose, 
 glucose. 
 
210 TJIE EGG IN KELATION TO SUGAR. 
 
 On looking at tbe above results, two points are noticeable — one, a 
 marked and speedy drop in the amount of sugar at the commence- 
 ment of emljryonic development, and the other, an alteration in the 
 character of the sugar, represented by a diminution of cupric oxide 
 reducing power. Two instances, it is observable, occur amongst the 
 undeveloped eggs, in which there was a similar drop in the amount 
 of sugar found, and the question suggests itself, on account of the 
 general accordance in the results, whether there might not here have 
 been some incipient development which had escaped observation. 
 
 The analyses, it may be stated, also included the determination, 
 by the process adopted for the estimation of glycogen, of the carbo- 
 hydrate matter contained in the residue from alcoholic extraction. 
 No alteration was discernible that could be considered attributable 
 to the influence of development. The same, it may be remarked, 
 was found to be the case with the figures expressive of the total 
 carbohydrate encountered. 
 
211 
 
 GLYCOGEN AND PROTEID-CLEAVAGE CARBOHYDRATE. 
 
 I have now to speak of the carbohydrate matter, other than sngar, 
 obtainable from the constituent parts of the animal system. After 
 the removal of sugar by alcoholic extraction, the residue still gives 
 evidence of the presence of carbohydrate. With certain tissues, this 
 carbohydrate consists, undoubtedly, to a greater or less extent of 
 glycogen — a principle the discovery of which resulted from the 
 masterly researches of Bernard. In addition, as I have shown in an 
 earlier part of this work when treating of the glucoside constitution 
 of proteid matter, the residue yields, under the process of analysis 
 which I have been in the habit of employing for the separation and 
 estimation of glycogen — namely, boiling with potash and precipitat- 
 ing with alcohol — a certain amount of carbohydrate material, not 
 identical witii, but closely allied to, glycogen. 
 
 As regards glycogen, it is well-known history that Bernard, in the 
 first instance, recognised it in the liver. Subsequent investigation 
 led to his recognition of it in muscle and in the lungs, whilst in uo 
 other tissue of the adult animal did he meet with it. In the prosecu- 
 tion of further research he detected it in cells belonging to the 
 amnion and placenta, and subsequently found it widely distributed 
 through the tissues of the foetus. From observing its presence in the 
 skin and its epithelial appendages, in the lining surface of the 
 alimentai-y cancl, in the ducts of glands opening into the alimentary 
 canal (not the glands themselves), in the respiratory surface, and in 
 the genito-urinary surface, of the embryo, he was led to regard it as 
 being concerned in the development of the limiting membranes. In 
 the liver he noted that glycogen did not make its appearance until 
 about the middle of intra-uterine life. In foetal structures other 
 than those mentioned, with the exception of muscle, ho did not detect 
 its presence. 
 
 In my own work in connexion with the liver, I, at an early period, 
 had recourse for the extraction and estimation of glycogen to a pro- 
 cess which consisted, as I have previously mentioned, in boiling with 
 
212 GLYCOGEN AND CLEAVAGE CARBOHYDRATE. 
 
 potasb, precipitating' with alcohol, boiling \yith dilute snlphurio acid, 
 and titrating with the amtnoniated cupric test solution. Circum- 
 stances afterwards led to my applying the process to other consti- 
 tnents of the body. I had happened to notice in the case of blood 
 that the residue from alcoholic extraction, on. being treated with 
 boiling water, yielded a product possessing a certain small amount of 
 cupric oxide reducing power be Pore treatment with sulphuric acid 
 and an amount considerably greater afterwards. This, after being 
 put to the test of enquiry, I concluded was due to the presence of 
 glycogen together with a little sugar which had escaped removal by the 
 alcohol. I was led now to apply the potash process made use of for 
 the separation of glycogen from the liver to the residue from the 
 alcoholic extraction of blood, and 1 found that it yielded a non-reduc- 
 ing substance precipitable by alcohol and convertible through the 
 agency of sulphuric acid into a reducing sugar. I afterwards applied 
 the process to the tissues and organs of the body generally, with the 
 result that in each case a similar product was obtained. 
 
 Unaware of wliat I have recently discovered with regard to the 
 glucoside constitution of proteid matter, I looked upon the product 
 obtained as consisting of glycogen. Research, however, has taught 
 me that the proteid entering into the constitution of the blood and 
 other component parts of the body yields, under the potash process 
 employed, a cleavage carbohydrate, which accompanies the glycogen 
 ■where such exists, and in the cases where no glycogen exists stands 
 alone as the source of the cupric oxide reducing product obtained. 
 
 I may mention here that in my former writings I have spoken of 
 glycogen (and, of course, with it was included the cleavage carbo- 
 hydrate from proteid) under the term " amyloid substance." As I 
 have previously stated, I look upon the term " glycogen " as a mis- 
 nomer, on account of the unsound phj'siological basis upon which its 
 application is founded. I have felt that the term " amyloid substance " 
 is one that simply expresses the nature of the material and involves 
 no physiological error, and, therefore, that its adoption in the place of 
 "glycogen " would be exceedingly desirable. The term "glycogen," 
 however, lias become so deeply rooted in chemical and physiological 
 literature, that to avoid complication I have considered it wise to sink 
 my own view on the matter, and have employed it throughout in this 
 work, instead of the term " amyloid substance " which I formei-ly used. 
 
GLYCOGEN AND CLEAVAGE CAEBOIIYDEATK 213 
 
 A new difficulty is created by tlie discovery of the cleavage cai-bo- 
 hydrate from proteid matter, as tbis passes with the glycogen in the 
 results yielded by analysis. I do not at present see bow they are 
 satisfactorily to be separately estimated. The results that follow 
 comprise the figures derived from both materials. When the analyses 
 were undertaken I was unaware of what has since been learnt about 
 the increased cupric oxide reducing power which results from the 
 employment of 10 per cent, as compared with 2 per cent, sulphuric 
 acid when the cleavage carbohydrate is being dealt with. As I have 
 shown (p. 37), the increase is to the extent of nearly doubling the 
 cupric oxide reducing power. It follows, therefore, that in the re- 
 sults given, since 2 per cent, was the strength of acid in all cases 
 employed, the cleavage carbohydrate is considerably under-estimated. 
 Moreover, a further source of uuder-estimation, it must be stated, 
 exists in connexion with the treatment with potash, for I have found 
 that if blood or other proteid-coutaining matter be mixed with 
 potash and allowed to remain in contact with it for several days 
 before being boiled, a larger amount of cleavage carbohydrate is ob- 
 tained than if the boiling is performed at once. The results given are 
 derived from analyses in which the boiling (with 10 per cent, potash) 
 was conducted without any previous prolonged standing, and thereforo 
 represent an amount of material short of what might have been 
 attainably obtained. They must, therefore, be only taken for what 
 they are really worth — that is, not as afEording full or precise informa- 
 tion of the state existing in the individual cases, but as giving an 
 approximate representation of the truth relating thereto, and with 
 this a correct representation of the comparative state of the different 
 specimens examined. It will be understood that the remarks which 
 have just been made do not apply to the estimation of glycogen. 
 Whatever of this principle may be present, is fully and accurately 
 represented by the process employed. 
 
 In the results that follow, then, the figures referring to the cleavage 
 carbohydrate are considerably under-stated. The cleavage carbo- 
 hydrate and glycogen I am obliged to express together, as they are 
 both yielded by the process adopted. For the sake of convenience 
 they will be comprised, assuming that the cleavage carbohydrate, like 
 glycogen, is of an amylose nature, under the term " amylose eai'bo- 
 hydrate," which will thus represent the carbohydrate obtained from 
 
214 GLYCOGEN AND CLEAVAGE CAUBOHYDEATE. 
 
 the residue from wliicli the sugai' has been removed by alcoholic ex- 
 traction. How much may be actually cleavage carbohydrate, or how 
 much, glycogen, it is impossible definitely to say. All I can venture 
 npon stating is that, in the results that follow, anything of account 
 beyond about 2 or 3, or po.ssibly 4, per 1000 may presumably be 
 regarded as due to glycogen. 
 
 Under the description of the analytical steps of procedure given in 
 a former part of this work, I referred (p. 63) to the fallacy that is 
 liable to be . occasioned by the employment of paper filters, through 
 contamination of the product with cellulose. Glass-wool was in- 
 variably employed as a filter medium in the analyses from which all 
 the results that follow were derived. 
 
215 
 
 BLOOD AND VARIOUS STRUCTURES OF THE BODY IN 
 RELATION TO AMTLOSE CARBOHYDRATE (PRO- 
 TEID-CLEAVAGE CARBOHYDRATE AND GLYCOGEN). 
 
 Blood. 
 
 Amongst a collection of observations taken under a variety of cir- 
 cumstances and conducted at various times, I find over a hundred 
 which may be selected as representative of ordinary or natural 
 conditions. In these the average figures yielded for the blood of the 
 general circulation stand at about 1 per 1000 or a little over, expressed 
 as glucose, the ordinary limits being from about 0'8 to 1'3. 
 
 As far as the results before me show, no evidence is afforded of 
 any appreciable influence being noticeable in the blood of the general 
 circulation as the effect of the ingestion of food. In the case, how- 
 ever, of the portal blood, a decided influence is perceptible, which 
 presents itself in its most pronounced form after the ingestion of starchy 
 food. Under these latter circumstances, the figures met with have 
 frequently stood as high as 2 to 2'5 per 1000, and in one case they 
 reached 27 per 1000. In a series of fifty-two observations upon 
 animals taken at a period of fasting, after animal food, and after 
 starchy food, the average figures for the portal and the cardiac blood 
 re.spectively stood as follows : — 
 
 
 Amylose carbobydrate per 1000, 
 
 At a period of fasting — 
 
 expressed as glucose. 
 
 Portal blood 
 
 113 
 
 
 1 12 
 
 After animal food — 
 
 
 
 1-35 
 
 Cardiac blood 
 
 1 08 
 
 After starchy food^ 
 
 
 
 1-79 
 
 Cardiac blood 
 
 1-07 
 
 Sugar introduced by injection into the general circulation appears 
 to lead to an increase of amylose carbohydrate in the blood. In some 
 
216 
 
 GLYCOGEN AND CLEAVAGE CARBOHYDRATE. 
 
 experiments upon rabbits wliere glucose from honey was injected 
 into the jugular vein, not only was a large amount of sugar afterwards 
 found, as shown at p. 189, but also, in most of the instances, an 
 unexpectedly large quantity of amylose carbohydrate. The figures 
 for the latter stood as follows in the several instances : — 
 
 Amylose carbohydrate, expressed as glucose, 
 per 1000 of blood collected from the heart. 
 
 Rabbits 
 kiUed 
 at once. 
 Three rabbits — 
 
 J gram of glucose per 
 kilo, of body-weight 
 injected into jugular 
 
 vein 2-26 
 
 Fire rabbits — 
 
 1 gram of glucose per 
 kilo, of body-weight 
 injected into jugular 
 
 rein 1-25 
 
 1-25 
 
 Rabbits Rabbits Rabbit 
 
 killed killed killed 
 
 after i hour, after 1 hour, after li hours. 
 
 In another set of experiments on rabbits, in which 1 gram of 
 loevulose per kilo, of body-weight was injected into the jugular vein, 
 the figures obtained stood as follows : — Killed at once, I'll; after 
 ^ hour, 154 ; after 1 hour, 1'67 ; and after 1^ hours, 1'67 per 1000. 
 
 D03.— 
 
 , r right leg 
 
 Hi 
 
 2^ 
 3 
 
 left leg 
 
 .fright leg 
 ' l.left leg.. 
 
 Muscle. 
 
 Amylose carbohydrate per 1000, expressed as 
 glucose. 
 
 Kxternal muscles. 
 
 58"! 
 
 53/ 
 
 25 1_ 
 
 13/ 
 
 67 
 
 14 
 
 34 
 
 23 
 
 95 
 
 67 
 
 » (fcetal pups) 11-3' 
 
 1-67 
 
 7-72 
 1-96 
 0-42 
 0-19 
 1-07 
 
 1-64 
 
 Diaphragm. 
 
 29-59 
 
 19 -ei 
 
217 
 
 5 . 
 
 6 . 
 
 Sieep.- 
 
 Fig.- 
 1 .. 
 
 Sabbit.- 
 1 ... 
 
 Amjiose carbohydrate per 1000, expressed as 
 glucose. 
 
 External muscles. 
 
 1 2U 
 
 2 2-69 
 
 3 219 
 
 ' fore leg , 
 hind kw. 
 
 3-22 
 3-26 
 
 0-81 "1 
 109/ 
 
 /foreleg 0-54,1 
 
 * I hind leg -.54 f 
 
 "55 
 •31 
 
 ;-67 
 
 t-50 
 !-18 
 
 113 
 1-26 
 1-42 
 2-15 
 
 1-54 
 1-21 
 
 Diaphragm. 
 
 In several observations upon muscle taken indiscriminately from 
 different rabbits, tlie figures obtained stood as follows: — 313 — 1'97 — 
 1-37— 1-25— 1-04— 1-00 and 0-67 per 1000. 
 
 Cat. — In eleven observations upon muscle taken indiscriminately, 
 the figures respectively obtained were — 14'62 — 9'24 — 7'35 — 6'80 — 
 6-79— 5-72— 5-93— 3-95— 3-20— 1-49 and 1-35 per 1000. 
 
 Fowl. — One observation. Muscle of breast, 0'50 per 1000. 
 
 Chouse. — One observation. Muscle of breast, 050 per 1000. 
 
 Tortoise. — Two observations. Muscle taken indiscriminately. 
 Figures given— 12-11 and 28-62 per 1000. 
 
 Frog. — Muscle obtained from two batches of fi-ogs. Figures re- 
 spectively yielded — 5-40 and 9'68 per 1000. 
 
 Fish. — Seven observations. Salmon 0'87^turbot 1-98 — cod 0'93 — 
 eel 0-37— eel 0-36— mackerel 0-33 and plaice 0-34 per 1000. 
 
218 GLYCOGEN AND CLEAVAGE CARBOHYDRATE. 
 
 Anijlose carbohydrate per 1000, 
 expressed as glucose. 
 
 I • ^ 
 
 Cruslucean. — Muscle of claw. Muscle of tail. 
 
 Lobster 1 4-13 1-62 
 
 2 '2-r& 1-16 
 
 3 0-37 0-42 
 
 Crab 1 1-77 — 
 
 2 6-15 — 
 
 Panceeas. 
 
 Doy.— Five observations. Figures respectively yielded — 2-21 — 297 
 —0-44— 075 and 3-20 per 1000. 
 
 Cat. — One observation. Figures given — 147 per 1000. 
 
 Sorse. — Five observations. Figures yielded — 4!-44 — 595 — 5-03 — 
 3-ti2 and 1-20 per 1000. 
 
 Sheep. — Five observations. Figures yielded — 2'31 — 2'02 — 2'74 — 
 2-15 and 3-54 per 1000. 
 
 Spleen. 
 
 Dog. — Seven observations. Figures respectively yielded — 1'04 — 
 2-36— 2-14— 1-67— 0-76— 2-07 and 1-18 per 1000. 
 
 Cat (spleens from a litter of sucking kittens). — One observation. 
 Figures yielded— 2-86 per 1000. 
 
 Horse. — Four observations. Figures given — 252 — 3 78 — 238 and 
 0-62 per lOuO. 
 
 Sheep. — Seven observations. Figures given — 4'07 — 3'27 — 2'08 — 
 2-77_0-94— 2-15 and 0-99 per 1000. 
 
 Kidney. 
 
 Dog. — Seven observations. Figures yielded — 1-34 — 1-30 — 051 — 
 0-45— 1-02— 1-13 and 0-57 per 1000. 
 
 Cat (kidneys from a litter of sucking kittens). — One observation. 
 Figures yielded— 1-97 per 1000. 
 
 Horse. — Four observations. Figures given — 3-86 — 1-55 — 213 and 
 1-54 per 1000. 
 
 Sheep. — One observation. Figures given — 1-25 per 1000. 
 
 Brain. 
 
 Dog. — Six observations. Figures given — I'OO — 091 — 0'70 — 0-3G — 
 0-51 and 104 per 1000. 
 
VARIOUS OKGAXS AND TISSUES. 219 
 
 LuN<: 
 
 Bog. — Two observations. Figures yiekletl — TiiS and (frotal pups) 
 5-02 per 1000. 
 
 Horse. — One observation. Figures yielded — 4'88 per 1000. 
 
 Intestinal Mucous Membkank. 
 
 T)oi]. — Under fasting. Two observations. Figures given — 3''0 
 and 310 per 1000. 
 
 Under a meat diet. Three observations. Figures given — 4 03 — 
 3-G9 and 3-10 per 1000. 
 
 Babhit. — At a period of digestion. Three observations. Figures 
 given— 1-73— 2-24 and 2-09 per lOOO. 
 
 Placenta and Fcetus. 
 
 Dog. — One observation upon placenta alone. Figures yielded — r83 
 per 1000. 
 
 Babbit. — Four observations. Figures given — placenta?, 22"55 — 
 associated foetuses, 3"12 — foetuses of another animal, 7'37 — placentse 
 and foetuses together, 2'51 per 1000. 
 
 Generative Structuees of Oviparous Animals. 
 
 Fowl. — Two observations. Ovarian egg.s, 4'6.3, and mucous 
 membrane of oviduct, 1179 per 1000. 
 
 Cod. — Two observations. Ovary (hard roe), 4'73, and testis (soft 
 roe), 2-20 per 1000. 
 
 Mackerel. — Two observations. Ovary (hard roe), 3'81, and testis 
 (soft roe), 3-30 per 1000. 
 
 Lobster. — Three ob.servations. Ovary, 811 — ovary, 10'97, and ova 
 adhering to the tail belonging to the same lobster, 800 per 1000. 
 
 Crab. — Two observations. Ovary with ova, 6'70, and testis with 
 ducts, 3-70 per 1000. 
 
 I must repeat what I before stated with regard to the value to 
 be attached to the above figures, namely, that they must only be taken 
 for what they are really worth — that is, as giving a comparative re- 
 presentation of the results obtained from different components of tlie 
 body by the same process of ti'eatment. Glycogen, when present, 
 
220 GLYCOGEN AND CLEAVAGE CARBOHYDltATE. 
 
 may be takeu as fully represenf-ed. The cleavage carbohydrate from 
 proteid matter is, I know, only represented to the extent of about 
 half the amount that is obtainable by using 10 per cent, instead of 
 2 per cent, sulphuric acid for conversion into sugar, and grounds exist 
 for believing that there is more carbohydrate material locked up 
 in proteid matter than is brought into view by boiling with 10 per 
 cent, potash in the first instance and the employment of 10 per 
 cent, sulphuric acid for subsequent conversion. 
 
221 
 
 AUTHOR'S CONCLUSIONS. 
 
 As tbe outcome of what has preceded, the views which have pre- 
 vailed since the promulgation of the doctrine giving to the liver a 
 glycogenic function must be absolutely abandoned. The edifice has 
 been constructed upon a false foundation, and nothing short of its 
 complete demolition will suffice to meet the requirements of physio- 
 logical truth. 
 
 A clearance of the ground is necessary in order that the new 
 material supplied by research may unimpededly be worked into 
 form from a new departure, based upon the sounder methods of ex- 
 perimental procedure placed at our disposal by modern science. 
 
 The experimental results I brought forward upwards of thirty 
 years ago, although standing confirmed by others, have not had the 
 fall meaning attached to them that I conceive should be given. For 
 my own part, throughout the long series of years mentioned, I have 
 never wavered for a moment with respect to the interpretation the 
 results in question should receive. 
 
 Formerly analytical knowledge was not sufficiently advanced to 
 permit of what the experimentalist observed being put into language 
 to secure the production of the same impression upon the mind as 
 would arise from actually seeing the results of the observations 
 themselves. All this is now changed, and quantitative sugar deter- 
 minations can te expressed with such precision as even to excite 
 surprise at what is attainable. I am constrained, therefore, to think 
 that, in view of the assemblage of facts presented in this volume, 
 the convictions which have so irresistibly taken possession of my own 
 mind cannot fail to penetrate into the minds of others. The error 
 existing has, I know full well, taken deep root in the belief of 
 physiologists, but I have no misgiving that, sooner or later, it will 
 come to be entirely eradicated, and that reference to animal glyco- 
 genesis, as it is now understood, will be expunged, except as a matter 
 of history, from works on physiology. 
 
 The question is one of great importance, standing as it does at 
 
222 author's conclusions. 
 
 the foundation of the connexion of the carbohydrates with aliment- 
 ation — in other words, of their disposal within the system — and the 
 comprehension of the nature and origin of tlie wrong action standing 
 at the foundation of the formidable disease — diabetes mellitus. 
 There are two aspects, therefore, presented, giving rise to a demand 
 of a weighty character for exact knowledge. By studying the 
 question from both aspects — physiological and pathological — the 
 investigator is placed in a more advantageous position for compassing 
 its elucidation than when the opportunity is afforded of studying it 
 from one aspect only. 
 
 The more extensive the field of observation, the larger the supply 
 of material upon which to generalise. It will not be disputed that 
 the physician and physiologist combined has a wider range of view 
 before him than either the one or the other separately. The physio- 
 logist works upon ground where normal action is at play, and seeks 
 to find out how the carbohydrates become naturally disposed of. The 
 physician has to deal with a departure from normal action, taking 
 the form of a failtire of power to properly dispose of carbohydrate 
 matter, and to prevent its elimination as sugar by the kidney. 
 
 It may, indeed, be truly said that in the consideration of the 
 physiological question I have derived immense advantage from my 
 experience in connexion with diabetes. Closely watching, as I have 
 done for years past, through the quantitative determination of sugar 
 in the urine, the relation between the sugar eliminated and the food 
 ino-ested, I have been placed in a position I could not otherwise have 
 attained. Without the knowledge thus supplied, I could not possibly 
 have expressed myself in the confident terms in which I consider I 
 am now able to do. 
 
 I will now proceed in a concise manner to review the arguments 
 springing from the facts adduced in this work which stand opposed 
 to the validity of the glycogenic doctrine. As carbohydrate matter 
 must, however, of necessity be in some way or other disposed of in 
 the system, we become confronted with the question of the manner 
 in which its disposal actually takes place. Until recently, all I 
 could assert was that carbohydrate matter became assimilated or 
 placed in a position to be susceptible of utilisation within the system, 
 instead of being allowed to reach the general circulation as sugar. 
 
KEFUTATIOX OF GLYCOGENIC DOCTIilKE. 223 
 
 aud thence to escape as waste material with the urine. By the per- 
 severing prosecution of research, however, I am now placed in a 
 different position. The key has been supplied which enables me to 
 follow the carbohydrates along the path taken by them in their appli- 
 cation to the purposes of life. Nothing but the disclosures of research 
 could have suggested to me the solution that has been presented. To 
 this matter I will direct attention after the clearance of the ground 
 has been effected from the views that have been hitherto entertained. 
 Reference to what has been said about the conditiou of the liver, 
 taken at the moment of death (pp. 133 — 138), and that of the various 
 other structures of the body (pp. 194 — 205), shows that it is not true 
 that the liver during life is, as has been alleged, in a more saccharine 
 state than other parts of the system. Practically speaking, the state 
 of the liver under physiological conditions is not essentially different 
 from that of the other structures I have examined ; and in the 
 case of muscle it has to be said that the amount of sugar present 
 may be very considerably beyond that found in the liver at the 
 moment of death. Sugar, in reality, exists as a normal constituent of 
 all the tissues and organs of the body. The liver, indeed, stands in 
 the same position as other structures, not only as regards the amount, 
 but likewise as regards the nature, of the sugar present. In the liver 
 taken for examination, without any precautions to prevent post- 
 viortem change, glucose is the kind of sugar met with. The sugar, on 
 the other hand, that is found in the liver at the moment of death 
 possesses, as shown by the analyses given (pp. 137 — 138), a cnpric 
 oxide reducing power more or less below that of glucose, in accord 
 ■ with what is seen to be the case in the analyses of the other struc- 
 tures of the body. 
 
 Thus one of the main tenets of the glycogenic doctrine is seen to 
 be absolutely untrue, the foundation for it arising from the error of 
 taking the post-niortem to represent the ante-mortem state. 
 
 Reference, further, to the experimental results representing tho 
 state of the blood belongiag naturally to life (pp. 110 — ^111 and p. 101 
 et seq.) shows that the blood flowing from the liver does not contain 
 more sugar, as it has been asserted to do, than that flowing to it. 
 Sugar is present throughout the contents of the circulation, in which, 
 iu fact, it may be considered to exist as a constitutional component, 
 as iu other parts of the .system. No appreciable difference is found 
 
224 authok's conclusions. 
 
 (pp. 166 — 171) in the amount contained in arterial and venous blood, 
 nor is there less, as has been alleged, in the blood of the portal vein 
 than elsewhere (p. 101 et seq. and pp. 158 — 171). The analyses given 
 show that even after prolonged fasting the portal blood contains 
 sugar similarly to the other parts of the circulation, and that after 
 the ingestion of carbohydrate matter it contains a great deal more. 
 Whilst, speaking precisely, the sugar present in the blood of the 
 general circulation ranges in amount from about 0'6 to about 1 per 
 1000, the amount in the portal blood after the ingestion of carbo- 
 hydrate matter may stand as high as 5, and upwards of this, per 
 1000. 
 
 The effect of what has been said is to show that there is no 
 evidence of the occurrence of the disappearance of sugar from the 
 blood in its transit through the systemic capillaries, assumed under 
 the glycogenic doctrine to take place ; and, correspondingly, no 
 evidence of the transport, as a functional operation, of sugar from the 
 liver to the systemic capillaries. 
 
 The liver, indeed, instead of actually throwing sugar into, or 
 allowing it to pass into, the general circulation, in reality checks the 
 progress of carbohydrate matter onwards. It prevents the fluctuating 
 condition, as regards sugar belonging to the portal blood, from 
 travelling on and being transmitted to the blood of the general 
 circulation. 
 
 Through the instrumentality of the liver, then, the blood of the 
 general circulation escapes being influenced by the ingestion of 
 carbohydrate matter. In the exercise of this office of the liver, the 
 sugar from ingestion contained in the portal blood is stopped and 
 converted into glycogen. Thus much is admitted by all, but it is 
 generally thought that the glycogen becomes subsequently recon- 
 verted into sugar to be transmitted on, serving only as a convenient 
 form of storage carbohydrate material. This implies that the sugar 
 of ingestion after all reaches the general circulation, and it is con- 
 tended that the object of conversion into glycogen is merely for the 
 sake of temporary storage — in other words, that at the time of active 
 absorption the carbohj'drate matter is detained, to be given out slowly 
 afterwards. Let us see how this argument stands the test of 
 criticism. 
 
 Concisely stated, it is asserted that when sugar from ingestion is 
 
REFUTATION OF GLYCOGEXIC D'OCTRINE. 225 - 
 
 passing in tlie portal blood to the liver it becomes, to a. greater or less 
 extent, temporarily stopped, to be given back into the circulation 
 when the entry from ingestion is not taking place. 
 
 In discussing the point I will, in the first place, direct attention to 
 circumstances existing in the case of the rabbit. In this animal the 
 stomach never becomes empty, as it does in animals generally. 
 Digestion is constantly proceeding, and, even aifter the lapse of 
 twenty-four hours from the ingestion of food, it is found that the 
 portal blood gives evidence of the presence of absorbed sugar by 
 containing more (vide p. 10.3) than naturally exists in the blood of 
 the general circulation. Assuming, a;s may fairly be done, that the 
 i-abbit does not ordinarily pass longer than twenty-four hours with- 
 out taking food, it follows that there will always exist in the portal 
 blood more sugar than in that of the general circulation. This is 
 tantamount to saying that under ordinarily prevailing circumstances 
 there is always a state existing calling for the exercise of a stoppage 
 action, which is not reconcilable with stoppage for temporary storage, 
 but, on the contrary, must involve arrest for application in some 
 other way. 
 
 From the condition of the urine looked at in relation to different 
 kinds of alimentation, which I will in the next place consider, we 
 obtain a strong point of evidence touching not only the limited ques- 
 tion of temporary storage but the whole question of tenability of the 
 glycogenic doctrine. 
 
 Healthy urine contains (p. 178) a certain amount of sugar. The 
 amount is in proportion to that existing in the blood of the general 
 circulation (p. 187). The blood and the urine, indeed, stand 
 throughout in accord with each other as regards sugar. When sugar 
 is present to a larger extent than usual in the contents of the general 
 circulation it correspondingly shows itself in the urine. Thus the 
 condition of the urine in relation to sugar moves with, and in fact 
 serves as an index of, that of the blood. Through the uiine, there- 
 fore, knowledge is supplied concerning the quantity of sugar that is 
 permitted to reach the general circulation. 
 
 Now, with the animal feeder, in which the ingestion of only a 
 limited amount of carbohydrate occurs (and even it may be said, in 
 the fasting animal where no ingestion is occurring) the urine stands 
 in the same position with respect to sugar as that of the vegetable 
 
226 AUTHORS CONCLUSIONS. 
 
 feeder, wbose food contains a large amount of carbohydrate matter. 
 The blood of the general circulation, in conformity with what has 
 previously been said, likewise corresponds in the two cases. With 
 the ingestion of the limited amount of carbohydrate, the blood and the 
 urine contain a certain amount of sugar. With the ingestion of an 
 amount incomparably greater, the same state of things is still 
 encountered. Both the blood of the general circulation and the 
 urine remain uninfluenced by the ingestion of carbohydrate matter, 
 80 long as it does not exceed ordinary limits. But stoppage from 
 entry into the circulation, through storage by the liver, cannot be 
 indeQnitely carried on, and, taking into account a lengthened period 
 of time, it is obvious that, if ingested carbohydrate were in reality 
 transported as sugar to the systemic capillaries, its transit in the case 
 where there has been free ingestion must proportionately add to that 
 existing where the ingestion has only been limited in amonnt. 
 Sooner or later the extra amount must pass through the circulation, 
 and where from day to day the quantity to pass is ten, twenty, or 
 thirty fold greater than under an animal diet, the addition must 
 present a source for the kidney to draw upon and thereby lead to a 
 proportionate presence of sugar in the urine. 
 
 With the limited ingestion associated with animal food, the urine 
 contains, as has been said, a certain amonnt of sugar. Any addi- 
 tional carbohydrate ingested should have the efEect of augmenting 
 this sugar, and of doing so in proportion to its extent. It is not, 
 however, in reality found that under ordinary circumstances the 
 urine gives evidence of being influenced by carbohydrate food. 
 Hence, for compatibility, we have to say that the passage of any 
 quantity of sugar into the circulation from carbohydrate matter 
 ingested within ordinary limits goes for nothing as regards effect 
 upon the urine, whilst influence is exerted by the known small 
 amount of sugar existing in the blood in association with an animal 
 diet and even w t'.i an absence of food. 
 
 The liver, in fact, instead of doing what is claimed for it under the 
 glycogenic doctrine, does exactly the reverse. It neither forms sugar 
 to be discharged into the general circulation and conveyed to the 
 tissues, nor temporarily stores up carbohydrate matter from ingestion 
 to be subsequently allowed as such to pass on. On the contrary, it 
 keeps the general circulation free from the sugar that would otherwise 
 
DIFFERENCE BETWEEN HEALTH AND DIABETES. 227 
 
 enter and sliow itself in the urine. Its office is an ari-esting one in 
 relation to carbohydrate matter, and if it were not for the exercise of 
 this office we should all be in the same position as the diabetic. It 
 furnishes a line of defence against the passage of carbohydrate in a 
 free state into the circulation, and thus prevents the sugar, derived 
 from alimentary absorption, which is contained in the portal blood, 
 from proceeding further. In proportion as the line of defence is 
 ineffectual, sugar will reach the general circulation and then the 
 urine. 
 
 As an outcome, the difference between health and diabetes may be 
 expressed in the following terms : — - 
 
 In health the capacity exists of stopping the onward progress into 
 the general circulation of the sugar derived from ingested carbo- 
 hydrate matter, when the ingestion stands within ordinary limits. 
 When the ingestion exceeds ordinary limits the capacity of arrest, 
 which is not unbounded, may not be equal to effijcting a complete 
 stoppage. A portion may in this way reach the general circulation, 
 and, in proportion as it does so, will appear in the urine. Hence the 
 explanation of the saccharine urine found to occur (p. 116) as an 
 accompaniment of excessive feeding with sugar. In further illustra- 
 tion, I may mention that the highest figures I have obtained for the 
 sugar in normal blood have been with rabbits which had been highly 
 fed with oats. In accord, the urine in these instances has given 
 evidence through the ammoniated cupric test of containing a lai'ger 
 amount of sugar than is ordinarily met with in healthy urine. 
 
 In diabetes, on the other hand, carbohydrate matter is not pro- 
 perly stopped and disposed of, but is permitted, instead, to reach 
 the general circulation in the form of sugar. The faulty state 
 presents itself in all stages of advance. Every grade of diversity 
 exists between the healthy state and the state belonging to the 
 severest form of diabetes. In some instances the capacity of stop- 
 page is only just below the normal. In these it is only when carbo- 
 hydrate matter is rather freely ingested that saccharine urine is 
 encountered. In others more and more impairment of the power to 
 check transmission into the general circulation exists, and in corre- 
 spondence less and less carbohydrate matter can be ingested without 
 appearing in the urine. 
 
 One point is linked with another, and my experience of diabetes 
 
 Q 2 
 
228 author's conclusions. 
 
 counts largely as a help towards enabling me to speak with the pre- 
 cision and confidence I am doing. Besides a large number of cases 
 seen in the course of my many years' hospital practice and in private 
 consultations outside my house, I have, extending up to the moment 
 at which I am writing, a record in my case-books of 2,642 cases seen 
 at home,- in all of which I Itave closely watched, under the most 
 varied circnmstamces and through the quantitative examination of 
 tlm urine, the elimination of sugar in relation: to the food ingested. 
 
 Now, the teachings of this experience point unequivocally to its 
 being contrary to the physiological order of events for ingested 
 carbohydrate to reach the general circulation in a free state to be 
 transnjritted to the systemic capillaries for destruction in some, it 
 must be said, unknown way. No other conclusion, I hold, is permis- 
 sible, and I have no misgiving that sooner or later this view will 
 meet with general acceptance. In fact, it is through the occuiTcnce 
 of what the glycogenic doctrine implies that diabetes is caused, and 
 the symptoms of the disease are due to sugar being allowed to reach 
 the general circulation. In proportion as it does so, a deviation from 
 the natural state is created by the sugar of the blood being raised 
 from its normal standard proportion. 
 
 The effect of dietetic treatment in diabetes stands in strict harmony 
 ■with the view adopted. As I have already said, the disease essenti- 
 ally consists of a loss, or of more or less impairment, of the power 
 which naturally disposes of ingested carbohydrate matter, and pre- 
 vents its reaching the general circulation in the form of free sugar. 
 Of the nature and effect of this power I shall speak later on. 
 
 Through the defective power existing in diabetes, sugar finds its 
 way into the blood of the general system, and, in proportion as it 
 does so, places it in an unnatui-al state, the effect of which is to inter- 
 fere with the performance of nutritive action, and of the processes of 
 life generally in a healthy manner. From the position held by the 
 blood, it is only in accord with what may reasonably be expected that 
 with an altered constitution it should, in proportion to the extent of 
 alteration, carry disturbance everywhere. 
 
 The deviation from the natural state, induced by ingested carbo- 
 hydrate matter being permitted to reach the general circulation, to 
 which the various troubles belonging to diabetes, it must be con- 
 sidered, are attributable, depends as regards degree, in the first 
 
NATURE OF FAULTY ACTION IN DIABETES. 229 
 
 place, upon the extent to which the impairment of the power of stop- 
 page exists, and, in the next, upon the amount of carbohydrate 
 ingested. The one is at the root of the disease, and if it could be 
 rectified all would immediately be set right. The other is under our 
 control, and by proper regulation of the diet much may be done to- 
 wards ameliorating the condition existing. It must be remembered 
 that animal as well as vegetable food contains a certain amount of 
 free carbohydrate; and, as I have shown in this work, sugar is set 
 free by digestion as a cleavage product from proteid matter. There- 
 fore, in all food a supply of carbohydrate matter is given from 
 without. This, in part, accounts for the sugar encountered in severe 
 cases where sugar is passed, notwithstanding restriction to a purely 
 animal diet. 
 
 I have said "in part " accounts for the sugar encountered ; for, in 
 severe cases, thei'e must be something further to be dealt with, seeing 
 that sDgar is even passed apart from the influence of food. There 
 can be no doubt that .sugar is susceptible of being derived from the 
 tissues, and, looking at what I have been led to propound with regard 
 to the glucoside constitution of pr-oteid matter, there is nothing unin- 
 telligible about it. On the contrary, in view of all the circum- 
 stances, it is a reasonable supposition that in connexion with the 
 altered state of things existing, a ferment becomes present endowed 
 with the power of wrongly splitting up the glucoside proteids of the 
 body in the same manner as, for instance, amygdalin is split up by 
 emulsin. 
 
 There is, then, a class of case in which the fault consists only of 
 a loss, or, it may be, varying degrees of impairment, of the power of 
 disposing of ingested carbohydrate matter in such a manner as to 
 prevent its reaching the general circulation ; and another, in which, 
 in addition to this, a condition within exists attended with the 
 splitting up, with sugar as a cleavage product, of the proteids of the 
 body. The former is completely controllable by dietetic manage- 
 ment, the latter only so to a partial extent. 
 
 Most cases, I will not go so far as to say all, are in the incipient 
 state controllable, with respect to the elimination of sugar, by diet. 
 In young subjects it is usual to find that the condition is observed to 
 remain only temporarily controllable. An insidious "something" 
 advances, carrying the case on into a more and more pronounced 
 
230 author's conclusioxs. 
 
 state of development. In subjects of more mature years, on the other 
 hand, if the morbid tendency is not encouraged by allowing the un- 
 natural condition, arising from the continued pervasion of the system 
 ■with sugar derived from defectively disposed of ingested carbo- 
 hydrate, to exist, it is usually observable that tbe case may be kept 
 indefinitely controllable. I may, even, go further and say that, under 
 strict and persevering attention to dietetic management, conjoined 
 with a certain form of drug treatment which I believe affords 
 material help, experience shows that a tendency to restoration is 
 promoted ; and that, as a result, whilst at first no starchy or sacchar- 
 ine food could be taken without giving rise to the elimination of 
 8u<Tar, in the course of time more and more power of properly dis- 
 posing of carbohydrate matter is acquired, leading to the toleration 
 of more and more carbohydrate matter in the food without giving 
 rise to saccharine urine until, it may be, the capacity for the resump- 
 tion of an ordinary diet is re-established. 
 
 It may be safely accepted that the point to be attained for pro- 
 moting the restoration of the power of properly disposing of carbo- 
 hydrate matter is to establish and maintain as close an approximation 
 as possible to the natural state as regards the blood, and thereby the 
 system throughout, in relation to the presence of sugar. On bringing 
 the position to a normal one in this respect, all the symptoms of the 
 disease at once disappear, whilst previously it may have been noticed 
 that they were more or less speedily growing. 
 
 I have seen it asserted, under the erroneous notion of there being a 
 functional transport of sugar to the systemic capillaries, that carbo- 
 hydrate articles of food ought not to be totally withheld even although 
 a considerable voidance of sugar may be occurring. This is equivalent 
 to saying that a deviation from the normal state as regards the blood 
 and the system throughout is to be disregarded. Moreover, even 
 if the premises were sound, the argument is illogical, as the voidance 
 of sugar affords proof that already the blood is surcharged with sugar 
 which is running off as waste material. To add more through the 
 medium of the diet would be simply to increase the surplus existing. 
 It is true, through failure of appetite and inability to take suflicient 
 food under restriction to the list of appropriate articles, reasonable 
 grounds for relaxing the diet may arise, but this is a totally different 
 matter. 
 
KATIONALE OF DIETETIC TREATMENT OF DIABETES. 231 
 
 Restriction from carbohydrate food should uot be carried further 
 than experience shows to be necessary, in the particular case under 
 consideration, to maintain a normal state of urine. The amount of 
 carbohydrate matter that can be taken -without leading to the void- 
 ance of sugar presents considerable variation in different cases, and 
 it happens that if what can be utilised is not supplied, a loss of body- 
 weight and failure of strength ensue. Often the complaint sets in 
 with only a slight diminution of the natural assimilative power, 
 presenting itself under the form of what is spoken of as glycosuria. 
 Under such cii-cumstances only a moderate restriction of diet is 
 needed to meet what is wanted. If more be enforced, loss of weight 
 will probably follow and the appearance be given that the treatment 
 is intlicting harm. By extending the liberty to that which the state 
 of the urine shows may be done without over-stepping the range of 
 toleration, immediate improvement will occur. Sach, in every case, 
 should constitute the principle of action to be adopted. 
 
 It may happen that restriction in diet is needed to be .enforced 
 to the full extent at the commencement of treatment, and not so 
 later on. An interesting sequence is noticeable in these cases. 
 The patient, it may be, has been the subject of diabetes for some 
 time without knowing from what he was suffering. The nature of 
 his malady becomes discovered, and he is placed, as a part of the 
 treatment adopted, on the restricted diet. He had been hitherto 
 steadily losing ground, but now his symptoms disappear ; he gains 
 in weight, and, altogether, in the course of a short time he becomes 
 restored to a greatly-improved condition. The treatment has a,t onoe 
 produced a niarked etTect upon the urine, but perhaps a little time 
 has been requiied to get it entirely free from sugar. It remains now 
 constantly free, and the patient continues to improve in health and 
 strength. After a while it may happen to be noticed that a change 
 begins to set in. Notwithstanding that the urine continues free from 
 sugar, the treatment, which before produced improvement, is now 
 attended with a retrogression in weight, and naturally the patient's 
 mind becomes disturbed from apprehension of a return of his 
 disease. 
 
 Instead, however, of ground for concern existing, my experience 
 informs me that the loss of weight under the circumstances men- 
 tioned is to be taken as an indication of restoration, to a greater oi- 
 
232 AUTIIOIi'S CONCLUSIONS. 
 
 less extent, of tlie power of properly disposing of carbohydrate 
 matter. The power existing, and the opportunity not being given 
 for its exercise, the want appears to be felt by the system. At all 
 events, in these eases I have confidence in concluding that on trying 
 a little starchy food (best, 1 consider, in the form of ordinary bread, 
 as the loss of this may be regarded as constituting the greatest 
 privation) it will be found not to give rise to the appearance of sugar 
 in the urine. On this proving to be the case, the amount should be 
 guardedly and gradually increased, short of leading to a return of 
 sugar. The result noticeable will be a speedy recovery and sub- 
 sequent maintenance of weight. 
 
 Remarkable, but nevertheless correct, to state, in cases where a 
 loss of weight does not, under corresponding cii'cumstances, super- 
 vene, my experience justifies the inference that the power of utilising 
 carbohydrate matter has not become raised, and that, consequently, 
 the inge.stion of starchy food will be followed by the appearance of 
 sugar in the urine. Thus, when the power of making use of starchy 
 food has been restored, and starchy food is not given, a loss of body- 
 weight is observed, whilst such is not noticeable where a restoration 
 of power has not occurred. Information is here supplied which in 
 practice I turn to account as a guide in the details of dietetic 
 management. Every case requires to be dealt with upon its own 
 merits, and for successful treatment a rational and intelligent plan of 
 procedure, founded upon a precise knowledge of the condition of the 
 urine, must be adopted. 
 
 The only point remaining for consideration is the manner in which 
 carbohydrate matter becomes disposed of in the system. This i-eally 
 is the most important point of all in connection with our subject, as 
 it deals with the purposes to which the carbohydrates are applied in 
 the economy ot life. 
 
 The glycogenic doctrine throws no light upon this matter. It 
 falls short of reaching the point. It assumes that carbohydrate 
 matter is thrown into the general circulation in the form of sugar 
 for functional transport to the systemic capillaries, but it fails to 
 proceed further, and to show in what manner the sugar is disposed 
 of. It simply leads into darkness, and nothing but fruitless efforts 
 have been made to obtain light in the direction looked for. This 
 
DISPOSAL OF CARBOHYDRATE BY PROTOPLASMIC ACTIOX. 2.33 
 
 is not, it may be said, to be wondered at, seeing that there is not 
 the functional transport that has been assumed to occur ; and that 
 the facts befoi-e us show that we must seek for the disposal of carbo- 
 hydrate matter before the opportunity is afforded of its reaching 
 the general circulation. To attempt to discover the manner of dis- 
 posal in a situation that the sugar does not naturally reach is not 
 likely to be attended with any satisfactory issue, and those who con- 
 tinue to prosecute enquiry upon such a foundation can scarcely fail to 
 be left endlessly groping in the dark. 
 
 There is no living matter without proteid, and probably even the 
 broader statement may be made, that there is no living matter with- 
 out proteid, carbohydrate, fat, and certain mineral constituents. 
 Carbohydrate matter may thus presumably be looked upon as univer- 
 sally diffused through the living kingdom of nature ; and, so cir- 
 cumstanced, it must have a comprehensive part to play in the 
 economy of life. In speaking of the manner in which it becomes 
 disposed of in the animal system, it seems to me that this considera- 
 tion should be held prominently in view. 
 
 If we look around and give attention to what is happening, it is 
 observable that certain changes are wrought upon carbohydrate 
 matter by the agency of living protoplasm. By virtue of the power 
 with which living protoplasm is endowed, carbohydrate matter located 
 within its sphere of influence is noticed, it may be said, to undergo: — 
 
 1. Transmutation ; 
 
 2. Application to the pi-oduction of proteid ; and 
 8. Transformation into fat. 
 
 The capacity for producing these effects may be regarded as con- 
 stituting a coumon property appertaining to protoplasm in an active 
 state, quite irrespective of which of our conventional divisions of 
 living nature the protoplasm belongs to. Universality of action is 
 traceable without distinction in the animal and vegetable kingdoms. 
 
 I will proceed to speak in detail of the disposal of carbohydrate 
 matter by protoplasmic action under the respective heads enumerated 
 above. From what has to be said upon the subject, I think it will 
 be seen that we need not seek further for the explanation that is 
 wanted to place the matter in a clear and intelligible light. Not 
 only do we find that an adequate explanation is presented to account 
 for the disposal of carbohydrate within the sj-stem, but that the seat 
 
234 author's conclusions. 
 
 of disposal is located just where it properly should be, in order fo 
 permit of escape from the production of a diabetic state — that is, 
 before the entrance to the general circulation is reached. 
 
 1 . — Transmutation. 
 
 The transmutation of carbohydrate matter was dealt with at some 
 length in an early part of this work (p. 18, et seq.), and it was seen 
 that, whilst ferments and chemical agents transmute by increase of 
 hydration — carrying, for instance, the principles of the amylose into 
 the saccharose and glucose groups — the effect of the influence exerted 
 by living matter is to reduce from the higher to the lower states of 
 hydration. For example, the sugar contained in the sap of the plant 
 is observed to be transmuted into cellulose, which constitutes a fabric 
 material of the organism, and into starch, jnulin, &c., which serve as 
 storage materials, and, in reality, contribute in the end to fabric 
 construction. 
 
 Through transmutation, carbohydrate matter meets with its chief 
 application in the vegetable kingdom, the celljilose from which the 
 fabric of the plant is constructed constituting an ultimate product. 
 I do not know whether it is to the full extent realised that the 
 storage carbohydrate of the seed, tuber, &o., passes in reality to the 
 same destination and that the process of storage only represents a 
 temporary halt on the way. By protoplasmic action certainly, and 
 probably by incorporation with nitrogenous matter into proteid and 
 transit through protoplasm, the sugar of the sap becomes transmuted, 
 apparently in each case in a similar manner, into fabric and storage 
 material. The storage carbohydrate, when exposed to conditions to 
 lead oa to its application, becomes first of all hydrolysed by ferment 
 action. Thus reconverted into sugar, it again stands in the position 
 it held in the sap from which it was taken for storage deposition ; 
 and now by the exercise of protoplasmic action in the developing 
 organism it is carried as a final step into cellulose, for it is from the 
 starch of the seed, &o., that the cellulose of the growing structure is 
 derived. 
 
 In the animal kingdom evidence is adducible of the occurrence of 
 transmutation in an analogous manner to what is observable in the 
 vegetable kingdom. Tiansmutation, however, does not here to a 
 
PROTOPLASMIC TKANSMUTATIOX OF CAKBOHYDPATE. 235 
 
 like extent lead on to application to texture construction ; indeed, it 
 is only to quite an insignificant extent that it does so. An example 
 is forthcoming in the deposition of cellulose as a texture basis of the 
 test or outer investment of the tunicata. 
 
 Transmutation, however, comes somewhat largely into operation in 
 reducing sngar to the state of a carbohydrate of lower hydration for 
 storage purposes. Glycogen is the form of carbohydrate into which 
 the sugar is in the animal transmuted, and it is interesting to notice 
 that in the tribe of organisms of the vegetable kingdom, which 
 are wanting in some of the attributes of plants, and present excep- 
 tional analogies to the animal, namely, the fungi, the storage carbo- 
 hydrate exists under the form of glycogen and not of starch. 
 
 A notable illustration in the animal kingdom of transmutation 
 by reduced hydration for storage is supplied by what occurs within 
 the liver. The sugar contained in the portal system, taking origin 
 from the carbohydrate matter ingested, is stopped by the cells of the 
 organ and transformed into glycogen. By transmutation into 
 glycogen the carbohydrate is checked in its onward progress to the 
 general circulation, and subsequently, it may be reasonably assumed 
 from all the knowledge at our disposal, meets with application 
 through one or both of the other methods of disposal of carbohydrate 
 matter by the agency of living protoplasm. 
 
 It is interesting to note that in tracing the sequence of events 
 occurring in the animal system in connection vrith ingested starch, 
 we have the same train of phenomena to deal with as in the growing 
 seed. The starch is first ti-ansrauted by ferment action — by diastase 
 in the one case and the amylolytic ferments of the digestive secre- 
 tions in the other — into sugar, a body susceptible of diffu.sion and of 
 transport in solution. By the portal system the sugar is conveyed to 
 the liver and brought within the sphere of influence of its cell-proto- 
 plasm. Here transmutation of the opposite kind to that before 
 occurring takes place, with the production of glycogen. By diffusion 
 the sugar taking origin from the starch in the growing seed arrives 
 within the reach of the power belonging to the living protoplasm 
 of the embryo, and, .as in the case of the liver, transmutation in the 
 direction of diminished hydration occurs, resulting here in the pro- 
 duction of cellulose. The same train of phenomena may be traced as 
 constituting a part of the life-history of the plant itself. The 
 
236 AfTIIOR's CONCLUSIONS. 
 
 primordial starch produced by the chlorophyll corpuscles in the leaf 
 reaches the sap as sugar, which on arriving at seats of protoplasmic 
 activity is transmuted down in hydration to fabric and storage carbo- 
 hydrate. The sap of the plant, looked at from the point of view in- 
 dicated, stands, it will be observed, in an analogous position to the 
 contents of the portal system of the animal. 
 
 I have referred to the protoplasmic transmutation of sugar into 
 glycogen in the liver. But the ti-ansmutative power by no means 
 e.Yclusively belongs to the liver — indeed, I am disposed to think that 
 it exists as a general property of the protoplasmic matter of the 
 body. Certainly, glycogen is recognisable, and even it may be 
 largely so, in other parts of the body, and it is probably produced at 
 its seat of presence. Every part of the body contains sugar in- 
 trinsically belonging to it, which may come from the cleavage of the 
 proteid matter around. The glycogen may be derived from this 
 sugar, or may possibly constitute a product of the cleavage process. 
 In the multifarious actions occurring in a living part there is, doubt- 
 less, much complexity of result arising from the antagonistic effects 
 of ferment and protoplasmic actions. 
 
 Further evidence is afforded through the kind of sugar found in 
 the urine after the direct introduction of glucose into the system of 
 the carbohydrate-transmuting power of living matter in the direc- 
 tion of a diminution of hydration, taken as represented by a diminished 
 cupric oxide reducing capacity. 
 
 At p. 189 I gave a description of experiments in which glucose, 
 derived from honey and proved by examination to have the same 
 cupric oxide reducing power before and after sulphuric acid, was 
 injected into the jugular vein. In two out of the three instances in 
 which urine was procurable the sugar eliminated was found to be in 
 a state considerably removed from glucose, the initial cupric oxide 
 reducing power belonging to it being considerably less than that 
 shown to exist after treatment with sulphuric acid. The results of 
 other experiments were also given, conducted with Isevulose derived 
 from the recently introduced trade article. Here, however, the 
 destructive action exerted upon the sugar by boiling with sulphuric 
 acid, in accordance with the known effect upon laevulose, >yas such as 
 to lead to considerably lower figures being obtained aftpr than before 
 treatment with the acid. From this counteracting circumstance no 
 
PnOTOPLASMIC TR.VXSMriATIOX OF CAltBOIIYDEATE. 237 
 
 opportuuity was given of ascertaining whether in reality any dimi- 
 nution of cupric oxide reducing power occurred. 
 
 It would hardly have been surmised that such results would have 
 been yielded. They agree, however, with the general tenor of ex- 
 perience set forth in this work which is to the effect that by the 
 agency of living matter the carbohydrates are moved within the 
 system in the direction of lessened cupric oxide reducing power 
 instead of in the reverse direction as happens as a consequence of 
 ferment action. Thus fitting in with and supporting, as they do, a 
 general principle of action shown by other evidence to be in opera- 
 tion, they acquire considerable importance. On this account, in 
 order that the point might be placed beyond doubt, I deemed it 
 advisable to undertake a further series of experiments, and I found 
 that I could simplify the operative procedure by injecting the sugar 
 solution into the subcutaneous tissue instead of into a vein. As will 
 be seen from the results to follow, confirmatory evidence was supplied, 
 and it may be considered to be established that sugar reaching the 
 general circulation as glucose, and thence brought into contact with 
 living protoplasmic matter whilst contained in the vessels and whilst 
 passing through the secreting structure of the kidney, escapes in a 
 form possessed of a lower cupric oxide reducing power than glucose. 
 
 The list comprises seven experiments conducted upon rabbits con- 
 secutively taken. In each ca'Se 1 gram of glucose (derived from 
 honey) per kilo, of body weight was injected into the subcutaneous 
 tissue of the back, the animal being temporarily placed under ether 
 for the performance of the injection. Urine was obtained from the 
 bladder about two hours afterwards. The delicacy of the ammoniated 
 cupric test is such as to permit of very small quantities of urine 
 sufiicing for analysis, and dilution to the extent of 30, 40, or 50 times 
 is requisite. The urine, suitably diluted, was divided into two por- 
 tions, one being titrated at once, and the other after boiling for an 
 hour and a half with 2 per cent, sulphuric acid under the inverted 
 condenser. In each case, as shown by the tabular arrangement given 
 of the results, the sugar present in the urine possessed a cupric 
 oxide reducing power much belo tv that of glucose, although glucose 
 was the form of sugar injected. 
 
238 
 
 AUTIIOK S CONCLUSIONS. 
 
 Nature and amount of Sugar in the Urine after the subcutaneous injec- 
 tion into the Babbit ofl gram of glucose per kilo, of body weight. 
 
 Cupric oxide 
 rediiiing power 
 of tlie sugar 
 Sugar eliminated in 
 
 per 1,000, relation 
 
 expressed to that of 
 
 as glucose. glucose at 100. 
 
 Rabbit I. 
 
 in c ■ i,t ■ 1 r before siJplmrie acid 4808 
 
 10 c.c. ot urine obtained . -^ ,., ' r-.-n 
 
 L alter „ „ 6ow9 
 
 Rabbit 11. 
 
 Q.c c ■ i_i. • 1 r before sulphuric acid 19'84 
 
 o t> ot urine obtained ....■{,■. ' r i ilo 
 
 L alter ,, ,, 51 b9 
 
 Rabbit III. 
 
 o„„ c ■ 1. ■ J r before sulphuric aci 
 o CO. 01 urine obtainea. . -^ j. '■ 
 
 { alter ,, ,, 
 
 acid 39-68 
 
 94-46 
 
 Rabbit IV. 
 
 . c ■ ut • J f before sulphuric acid 34-72 
 
 4 c.e. 01 urine obtained • • -i , f i f Q-44 
 
 Rabbit V. 
 
 Over 15 c.c. of urine 
 obtained 
 
 r befoiv 
 \ after 
 
 e sulphuric acid 21 '74 
 35-72 
 
 Over 30 c.c. of urine f before sulphui-ic acid 10-41 
 
 obtained . 
 Rabbit VII. 
 
 e r befort 
 |_ after 
 
 1923 
 
 , , . . . . ■ 1 f before sulphuric acid 48-/8 
 
 4 1 c.c. of urine obtained. < ,, ' nn.c 
 
 Latter „ „ 110 8a 
 
 The above results very strikingly- show that the amount of cupric 
 oxide reducing power after treatment -with sulphuric acid greatly ex- 
 ceeded that existing before. It is asserted tliat animal gum, an 
 amylose carbohydi-ate, may exist in the urine. If present, it would 
 serve to account for the diiierence revealed in the results obtained. 
 To ascertain if the difference were attributable to such a source, a 
 portion of the urine in three of the experiments was poured into a 
 large quantity of absolute alcohol. The effect of this upon animal 
 gum would be to precipitate it. After standing for twenty-four 
 hours the alcohol was filtered off, evaporated down, and the product 
 subjected to titration with the amnioniated cupric test before and 
 after treatment with sulphuric acid. The results obtained revealed 
 the same kind of difference as was noticed in the original examina- 
 tion, thus rendering it evident that the phenomenon observed must 
 be ascribed to the presence of sugar with a loner cupric oxide reduc- 
 ing power than that of glucose. 
 
ArPLICATION OF CAUBOIIYDRATE TO PROTEID PKODUCTIOX. 239 
 
 I have mentioned that a certain amount of sugar exists in normal 
 urine, and the evidence before me points to the nature of the sugar 
 standing in accord with what has been mentioned above in exerting 
 an increased cupric oxide reducing action after treatment with sulph- 
 uric acid. 
 
 The kind of sugar eliminated in diabetes is, on the other hand, 
 ordinarily glucose. I have had a number of examinations made, and 
 it is only in a few instances that a sugar with a lower cupric oxide 
 reducing power has been met with. 
 
 2. Application to the Production of Proteid, 
 
 The observations of Pasteur upon the growth of yeast may be 
 considered to reduce to demonstration the production of proteid by 
 the agency of protoplasmic action from the incorpoi-ation of carbo- 
 hydrate with nitrogenous matter. The question was considered in 
 an early part of this work (p. 53, et seq.), and it was there shown that 
 yeast cells, which consist of little masses of living protoplasm, placed 
 in a medium composed only of sugar, tartrate of ammonia (nitrate of 
 ammonia, which has no carbon entering into its constitution, and, 
 therefore, renders it absolutely evident that the carbon of the newly 
 formed proteid must be derived from the sugar, may be substituted 
 for the tartrate), mineral matter, and water, grow and multiply — a 
 fact which implies that fresh protoplasm, and hence proteid, must 
 be produced. The conditions here are so simple as to leave no room 
 for hesitation in accepting the conclusion to which they lead up. 
 
 Upon the strength of what is observable in the higher vegetable 
 organisms, it is likewise affirmed in settled terms by vegetable 
 physiologists that carbohydrate matter is utilised in the production 
 of proteid by incorporation with a nitrogenous principle (vide pp. 64 
 — 56). Asparagin, a crystallisable and diffusible nitrogenous prin- 
 ciple widely dispersed through the vegetable kingdom, appears to play 
 an important part in connexion with the operation. Sachs, in his work 
 on the ' Physiology of Plants,' in several places speaks of it as an 
 established point that from carbohydrate matter and asparagin proteid 
 is formed, and further asserts that the converse process of splitting 
 up of proteid with the liberation of asparagin, for fresh service in the 
 same direction, likewise constitutes an operation occurring in associa- 
 tion with metabolic activity. Other nitrogenous principles may take 
 
240 author's conclusions. 
 
 the place of asparagin, and with the supply of the uitrogen-contain- 
 ing compounds, on the one hand, from the soil, and the production of 
 carbohydrate in the leaves from the carbonic acid of the atmosphere 
 and the elements of water through the influence exerted by the sun's 
 rays, we have before us the source of the principles entering into the 
 constitution of proteid matter. 
 
 It is, then, distinctly affirmed that proteid in the plant is con- 
 structed from carbohydrate matter and asparagin, or some other 
 nitrogenous principle, by the agency of protoplasmic power, and, 
 further, that a dissolution of the proteid thus formed afterwards 
 takes place, with the liberation of asparagin, which again enters into 
 the constrnction of proteid by conjugation with fresh carbohydrate 
 matter. Nothing is here said by Sachs about carbohydrate issuing aa 
 a cleavage product from the proteid, although it is spoken of as con- 
 stituting the complementary part to the asparagin in the process of 
 construction. Elsewhere, it is true, reference is made to protoplasm 
 being concerned in the deposition of starch, &c., as storage, and 
 cellulose as fabric material, but the question is not pursued to any 
 further extent. Looking, however, at all the knowledge in our pos- 
 session, I am led to go on and say that the weight of evidence and 
 probability is in the direction of proteid constrnction constituting an 
 important intermediai-y in the physiological progression of carbo- 
 hydrate matter. Through its glucoside constitution, proteid matter 
 stands as an important factor in the play of changes connected 
 with life, into which the carbohydrates enter. 
 
 Let me carry the discussion into the domain of materiality, and take 
 for illustration a growing bud. At the seat of metabolic activity 
 asparagin is produced by the dissolution of previously formed 
 proteid matter. The asparagin thus originating exists in contact 
 with sugar continuously being derived from the starch taking its 
 source in the chlorophyll corpuscles under the operation of the solar 
 energy. Through the instrumentality of the living protoplasm within 
 the sphere of influence of which the two principles are lying, in- 
 corporation into proteid takes place with the contemporaneous growth 
 of protoplasm. Observation testifies that where the protoplasm has 
 existed, fabric cellulose becomes deposited, and, from a review of all 
 the circumstances, it may be looked upon as probable that the depo- 
 sition occurs as the result of proteid cleavage, with the concurrent 
 
APPLICATION OF CAKBOHYDKATE TO PKOTEID I'liODUCTION. 241 
 
 liberation of asparayiu to contribute to a repetition of the operation 
 with, fresh carbohydrate matter, generated by the stax-ch-forming 
 chlorophyll. Under the view presented, the protoplasm of the grow- 
 ing part incorporates into itself the newly formed carbohydrate, and 
 subsequently leaves it behind as lignified cellulose in its track, just as 
 a coral polype incorporates into its substance calcareous matter 
 which it leaves behind in the form of the coral structure as it 
 grows on. 
 
 The account that has been given will equally apply to the growth 
 of the seed and the shoot of the tuber, the only difference being that 
 the new organism di-aws its carbohydrate from storage material in- 
 stead of from a generating source. 
 
 Economy of nitrogenous matter is noticeable in the process de- 
 scribed. A certain amount, it is true, of the protoplasmic nitrogen i.s 
 left behind with the fabric carbohydrate, and in connection with the 
 storage carbohydrate there is evidently a special deposition of nitro- 
 genous matter to meet the requirements of the growth subsequently 
 to take place ; but with the repeated service of asparagin that has 
 been alluded to, an economical provision, as regards nitrogenous 
 matter, exists for bringing about the utilisation of a large amount of 
 carbohydrate material. 
 
 I have drawn proof of the production of proteid by the incorpora- 
 tion of cai'bohydrate with nitrogenous matter through protojjlasmic 
 power, from the actions occurring in the vegetable kingdom. Ac- 
 cording to the view I am propounding, the disposal of carbohydrate 
 matter in the several ways to which I am referring is the result of an 
 attribute or pov/er belonging to living pi'otoplasm, without distinc- 
 tion as to which of the conventional kingdoms of nature it happens to 
 fall into. I will proceed to adduce evidence pointing to the utili- 
 sation of carbohydi-ate in the animal kingdom in the production of 
 proteid matter ; but, before doing so, I may remark that what has 
 been said in this work about the glucoside constitution of proteid 
 matter gives very great support to the whole proposition. Utilised 
 in the formation of proteid, it is only in accord with what might be 
 expected that it should be susceptible of withdrawal under the 
 operation of influences effecting a disruption of the proteid molecule. 
 The two stand in harmony, and mutually substantiate each other. 
 
 We start with the carbohydrate matter derived from ingestion in 
 
242 AUTHOU'8 CONCLUSIONS. 
 
 tlie alimeutary canal. The cliief portion takes rise from free carbo- 
 hydrate contained in the food, but a portion (p. 50) issues from the 
 cleavage of the proteids of the food by the proteolytic ferments of the 
 digestive tract. From whatever source starting, carbohydrate 
 matter in the form of sugar is lying in association with the nitro- 
 genous product of proteolytic ferment action — peptone — within the 
 sphere of influence of the extremely active little masses of protoplasm 
 constituting the cells covering the villi. The circumstances here 
 present no essential difference from those existing in Pasteur's ob- 
 servation. For the yeast cells we have only to substitute the cells of 
 the villi ; and, one kind of protoplasm having the power of conjuga- 
 ting carbohydrate and nitrogenous matter into proteid, it may not 
 unreasonably be looked for that the other should also be endowed 
 with it. 
 
 I have shown that the portal blood, after the ingestion of carbo- 
 hydrate food, contains considerably more sugar than is met with in 
 other parts of the circulatory system. From the application of the 
 analytical procedure for obtaining cleavage carbohydrate from pro- 
 teid matter, it is learnt that higher figures are here also given than 
 by the blood existing elsewhere. This matter is referred to at p. 215 
 et seq., and it is there further seen that, after the injection of sugar 
 into the jugular vein of rabbits, the contents of the circulatory 
 system furnished considerably larger amounts of amylose carbo- 
 hydrate than under other cii'cumstances has been found. The evi- 
 dence upon the point, taken in its entirety, certainly tends to show 
 that the presence of carbohydrate leads to increased results being 
 yielded by the analytical procedure for obtaining cleavage carbo- 
 hydrate, thus falling in with the view propounded regarding the 
 application of carbohydrate to proteid formation. 
 
 What is noticed with regard to peptone stands in harmony with 
 the disposal under consideration of carbohydrate matter. By the 
 proteolytic ferments of the digestive system, the proteid molecule is 
 split up with the production, as is well known, of peptone ; and, as I 
 have shown in an earlier part of this work (p. 50), of sugar. This 
 is the first step in the application of proteid matter as food. Thus 
 broken up into more simple principles, it is jjlaced in a suitable state 
 for the exercise of the synthetic action of the living protoplasm 
 within the sphere of influence of which the products lie. Peptone 
 
APPLICATION OF CARBOHYDKATE TO PROTEID PKODUCTION. 243 
 
 may be regarded as standing in tlie position of asparagin and otlier 
 allied nitrogenous priuciples of the vegetable organism, and also, it 
 may be said, of the tartrate of ammonia in Pasteur's yeast culture 
 liquid, in relation to the production of proteid. Its incorporation 
 with carbohydrate matter by the agency of the synthetic power with 
 which living protoplasm is endowed, suffices to account for the pi'O- 
 duction in the same manner as occurs in living nature generally of 
 the proteid matter into which, by common consent, it is conceded to 
 pass. Nowhere, perhaps, does more active protoplasm exist than in 
 the investing cells of the villi ; and it is doubtful whether sufficient 
 attention has been given to their importance as protoplasmic instru- 
 ments of action in the economy of the living animal. The altered 
 characters they present during digestion, as compared with fasting, 
 testify to their activity. Their number must be extremely great, 
 and if, instead of being spread over a free expanse of surface, they 
 were packed into a glandular mass constructed after the usual 
 fashion, a good sized organ would result. The position they occupy 
 does not in reality detract from the exercise of an assimilative office 
 as effectually as if they were arranged in a compact gland ; and any 
 other position than that of being spread around the alimentary tract 
 would be incompatible with applicability to meet the requirements 
 associated with food. 
 
 Now, peptone disappears from view just where it should do under 
 the view that it is utilised in the production of proteid by the agency 
 of the cells of the villi, or, speaking more generally, the cells belong- 
 ing to the inner surface of the intestinal canal. The presence of 
 peptone is easily demonstrable within the alimentary canal, but it is 
 not to be discovered in the contents of the general circulation, nor 
 even in the portal blood or chyle. Its disappearance is spoken of by 
 physiologists as being involved in a certain amount of mystery ; and 
 it is stated that all that can be definitely said is that the mucous 
 membrane constitutes the seat of its conversion into proteid. Giving, 
 however, to the investing cells of the villi the same power that proto- 
 plasm existing elsewhere is endowed with, there is nothing myste- 
 rious in the disappearance of peptone where observation shows that 
 it occurs. Indeed, with the presence of peptone and sugar in the 
 alimentary canal, and the .synthetic influence of protoplasm within 
 reach to exert its action upon them, the disappearance of the former 
 
 E 2 
 
244 author's conclusions. 
 
 by incorporation into proteid is only what might be looked for. The 
 chief channel through which the newly-formod proteid is conveyed 
 into the system is probably the lactcals ; but, ajiparently, a certain 
 proportion reaches the portal blood. 
 
 Thus, the points that have been referred to respecting peptone give 
 support to the view that has been propounded with regard to the 
 application of carbohydrate matter to proteid formation through the 
 medium of the protoplasmic power of the cells of the villi. 
 
 Other considerations of a more general nature tend to show that 
 the nitrogenous portion of our food is concerned in the assimilation 
 of carbohydrate matter. Where it is deficient, evidence is aiforded 
 that the carbohydrates do not become applied within the system in 
 the same beneficial manner as where it is present in due proportion. 
 The food must contain a certain quantity of nitrogenous matter for 
 the ciirbohydrate portion of it to be tui-ned to proper account. The 
 absorbed material which escapes application by the protoplasm of 
 the investing cells of the villi reaches the jiortal blood and thence 
 the liver ; and it is found that in proportion as carbohydrate food 
 is in excess, so does the liver become charged with transmuted sugar 
 under the form of glycogen. In the laboratory, advantage is taken 
 of this fact when it is desired to procure glycogen in quantity. 
 
 I look upon it that there can actually be no doubt that one of the 
 purposes to which the carbohydrates are applied in the economy of 
 life is participation in the production of proteid matter. Such being 
 the case, the position assigned in Liebig's classification to the nitro- 
 genous constituents of food as exclusively representing the flesh- 
 forming principles, can no longer be considered to hold good. With 
 incorporation into the proteid molecule, carbohydrate matter contri- 
 butes in reality to flesh formation ; and, universally distributed 
 throughout the system in this state, it rejDresents a large amount of 
 locked-up carbohydi-ate existing in the body. Thus circumstanced, 
 it stands in a position to permit of its retention, and possible further 
 utilisation, in contrast to the condition existing in diabetes, where, 
 reaching the general circulation in a free state, it passes oif as 
 unused material with the urine. 
 
 A few pages back I spoke of proteid, through its synthesis and 
 cleavage, constituting a medium for the utilisation of carbohydrate 
 {natter in the vegetable kingdom. The same probably occurs in the 
 
TRANSFORltATION OF CARROHYriRATE INTO FAT. 245 
 
 animal kingdom. For instance, on looking at the various surroimdings 
 of the case, the idea, it seems to me, that most satisfactorily accounts 
 for the origin of the lactose, fat, and casein of milk is that they all 
 constitute cleavage products from proteid matter. Casein, it happens, 
 as I mentioned (p. 32) when speaking of the glucoside constitution of 
 proteid matter, differs strikingly from the other proteids examined in 
 yielding quite an insignificant amount only of cleavage carbohydrate — 
 a condition that harmonises with what might be looked for on the 
 hypothesis of its cleavage origin. The sugar met with in the several 
 structures of the body may take origin from proteid cleavage. In the 
 advanced stage of severe cases of diabetes, some of the sugar elimi- 
 nated is evidently di-awn from the tissues of the body. An excessive 
 cleavage of proteid, arising from the particular state existing, 
 adequately affords the explanation wanted. 
 
 (3). Transformation into Fat. 
 
 The question of whether it is possible for cai-bohydrate matter to 
 be transformed into fat in the animal system was the subject of warm 
 conti'oversy during the first half of the present century, and several 
 names of renown stand associated with it. The settlemcnb then 
 arrived at was in the affirmative, and the advance of knowledge that 
 has since taken place attests the correctness of the conclusion. The 
 animal kingdom, indeed, it may now without hesitation be asserted, 
 stands in the position of a large constructor of fat from the carbo- 
 hydrate matter constituting the primordial organic production sup- 
 plied to the living kingdom of nature by the vegetable organism 
 operating under the influence of the power derived from the sun. 
 
 If it be true, as is believed, that carbohydrate matter represents 
 tbe initial condition of all organic products, the whole of the fat 
 encountered in both kingdoms of living nature must take its origin 
 directly or indirectly from carbohydrate matter. From the nitrogen- 
 containing compounds and mineral matter supplied to the plant 
 through the roots, and the carbohydrate matter produced by the 
 leaves, we have the basis for the construction of the various complex 
 organic products that exist. Now, evidence is adducible from which 
 the conclusion may be drawn that fat is susceptible of taking origin 
 from these complex organic products by dissociation, brought about 
 
246 author's conclusions. 
 
 in the presence of certain conditions. We do not in this case 
 discern, upon a superficial view of the matter, any direct connexion 
 between fat and carbohydrate, but, if carbohydrate is the source of fat 
 and all the carbon compounds of living nature, the fat must, whatever 
 the intermediate stages that may have existed, have tiltimatcly taken 
 origin from it. 
 
 From what has been said, however, in this work about the origin 
 and the constitution of proteid matter, the sequence of events 
 becomes intelligible. In view of chemical experience, there is 
 nothing unreasonable in the proposition that carbon may enter the 
 proteid molecule as carbohydrate, and come out from it in the form 
 of fat. Under one set of conditions the cleavage may be attended 
 with the liberation of a carbohydrate, and, under another, with that 
 of fat. Even with the direct production of fat from cai'bohydrate, 
 there may be passage through proteid matter. Certainly, protoplasm 
 is a necessary factor in the process, and there are grounds for con- 
 sidering it more than probable that the result is attained through 
 incorporation and liberation, rather than by direct transformation. 
 Should the former supposition be right, there is no essential difie- 
 rence between the production of fat, as an act of assimilation, from 
 carbohydrate and the origin of fat, by the cleavage of proteid matter 
 belonging to the textural constituents of the body, which takes jjlace 
 to a prominently marked extent in fatty degeneration. 
 
 The growth of yeast cells in Pasteur's sugar pabulum has been 
 already taken advantage of to illustrate the transmutation of carbo- 
 hydrate matter from a higher to a lower state of hydration, and its 
 application, in the presence of a nitrogen-containing compound, to 
 the construction of proteid. The example in question may also be 
 made use of in connexion with the further point that is under con- 
 sideration, inasmuch as it likewise serves to illustrate the production 
 of fat from carbohydrate. Yeast, as Pasteur and others have shown, 
 contains at least I to 2 per cent, of fat. Its growth in a medium 
 containing no fat, and with sugar as the only possible source of it, 
 which is the case when the nitrate of ammonium is substituted for 
 the tartrate of Pasteur's liquid, affords conclusive proof of the 
 convertibility of carbohydrate into fat. 
 
 The fact of the production of fat from carbohydrate is abundantly 
 attested by examples that can be di-awn from the higher forms of 
 
TRANSFORMATIOX OF CARBOHYDRATE INTO FAT. 247 
 
 vegetable organisation, in some of wbicli it is very extensively 
 carried out. 
 
 In the oily seeds the fat is preceded by starch and sugar. Sachs* 
 says " Before maturity such seeds contain no fat, but only starch and 
 sugar. Such unripe seeds (e.g., of Pceoma) may be detached from the 
 mother plant, and allowed to lie in moist air with the result that 
 the starch disappears and is replaced by fatty oil." Again,t " There 
 is not the slightest doubt that fat is formed in ripening seeds from 
 carbohydrates, particularly starch, since this transformation takes 
 place in the nearly ripe seed, even when taken out of the fruit, when 
 no other material is available under the circumstances for the forma- 
 tion of fat." 
 
 If, as appears in the oily seeds, it is susceptible of demonstration 
 that fat is produced from carbohydrates, it is equally demonstrable 
 that carbohydrates are reciprocally producible from fat. The embryo 
 of the oily seed gi-ows in the same manner, and, in its growth, 
 develops the same kind of structure as that of the starchy seed. 
 The cellulose and other carbohydrates found in the seedling are 
 obviously derived from the fatty reserve in the one case, just as they 
 are derived from the starchy reserve in the other. 
 
 However inexplicable, from a strictly chemical point of view, such 
 transformations may be, the fact is evident that in the oily seeds 
 fatty matter is, in the first instance, produced from carbohydrate, 
 and, subsequently, in the growth of the seedling, reconverted into 
 carbohydrate. 
 
 In the animal kingdom fat is, without question, produced upon a 
 very extensive scale from the carbohydrates. The animal system 
 constitutes, in fact, a laboratory wherein the capacity exists for con- 
 verting carbohydrate matter into fat. In the milch cow, in the 
 fattening of animals for the table, and in the production of the foie 
 gras in the Strasburg goose, we have instances of the extensive 
 operation of the process, and I need not dwell further upon the 
 question of fact, but will proceed to consider that of where and how 
 the change is brought about. 
 
 The ferments of the digestive system place the carbohydrate matter 
 
 * ' Lectures on the Physiology of Plants,' by Julius von Sachs. Translaf.ed by 
 H. Marshall Ward, p. 323 : Clarerdon Press, Oxford, 1887. 
 t Loc. cit., ]). 384-. 
 
24<S author's conclusions. 
 
 of our food in a soluble state, if not already existing so. The small 
 intestine is tlie part of the alimentary tract where absorption of 
 the nutrient matter specially occurs, and, here, the carbohydrate is 
 intimately intermixed with the product of digestion of niti'Ogenous 
 matter. Thus prepared, the carbohydrate product falls, in the 
 process of absorption, within the sphere of influence of living proto- 
 plasm represented by the cells investing the villi. These cells are 
 recognised as the agents concerned in the absorption of fat, but no 
 thought appears to have been given to them as transformers of 
 carbohydrate into fat, although, if we bestow attention to the matter, 
 evidence is seen to be forthcoming suggesting that they, in reality, 
 fulfil this function. 
 
 It is well known that after food rich in fatty matter the lacteals are 
 charged with milky chyle, that the cells of the villi are more or less 
 loaded with fat, and that fat globules pass from these cells through 
 the centre of the villus to reach the current in the lacteal system. 
 
 Observation conducted upon the vegetable feeder after the inges- 
 tion of food rich in carbohydrate matter and poor in fat reveals the 
 existence of a precisely similar state of things. On taking, for 
 instance, a rabbit about four hours after a meal of oats, killing it, 
 and opening the abdomen, coils of the small intestine are seen, 
 especially after a few minutes' exposure, to present a white opaque 
 appearance, with milky streaks or lines upon the surface, due to flow 
 of chyle beneath the peritoneum ; and the lacteals of the mesentery, 
 owing to the milky character of their contents, are conspicuously 
 visible. The receptaculum chyli is also, from the same cause, readily 
 perceptible, and, if cut into, gives exit to a strongly milky fluid. On 
 the intestine being laid open, a more or less densely white condition 
 of the internal surface presents itself to view, due to the extent to 
 which, the mucous membrane is charged with fat, and the villi stand 
 out as opaque projections. 
 
 In order that the condition described maybe satisfactorily visible, it 
 is necessary that favourable circumstances should exist. The animal 
 itself must be in a good healthy state. The food must be of a natural 
 kind and sufficiently rich in farinaceous constituents. Moistened 
 oats, in the case of rabbits, have yielded the most marked results. 
 After fasting, with unfavourable food, and in ill-conditioned animals 
 the appearance strikingly diifers. The intestine is transparent and 
 
TRANSrOEMATIOX OF CARBOHYDRATE IXTO FAT. 249 
 
 watery, and the lacteals are not perceptible. Between this condition 
 and that in which the lacteals are fully injected, any intermediate 
 degree of milky character may, of course, be perceptible. 
 
 From the appearances presented, then, to the naked eye, it is learnt 
 that under suitable food, rich in starchy matter, the same passage of 
 fat through the lacteals occurs as after feeding directly with fat. It 
 seems to me impossible that the quantity of fat observed to be thus 
 entering the system could be derived from that contained in a free 
 state in the food. Analysis of the oats consumed in my experiments 
 placed the amount of fat present at 5 per cent., which agrees with the 
 estimations made by others. 
 
 Upon the facts before us, the following train of reasoning may, I 
 am of opinion, be legitimately set forth. We know, upon irrefutable 
 grounds, that the capacity of producing fat from carbohydrate matter 
 exists within the animal system, and must be extensively in opera- 
 tion. The intestine constitutes the main seat of preparation of 
 carbohydrate matter for absorption and subsequent utilisation, and 
 from the intestine we find fatty matter flowing into the system 
 through the lacteals, which cannot be adequately accounted for, 
 except on the hypothesis of its oi-igin from the carbohydrate matter 
 of the food. Indisputably, the formation of fat takes place some- 
 where in the system, and there is no situation more propitiously 
 circumstanced to meet all the requirements of the problem than the 
 intestinal villi. Moreover, with the seat of formation in this position, 
 the introduction of fat into the system as a production from carbo- 
 hydrate food, is brought into conformity with its direct introduction, 
 preformed, from without. In the one case, the fat is simply absorbed, 
 and reaches the lacteals; in the other, it is jDroduced by assimilation 
 from carbohydrate matter, and then similarly reaches the lacteals. 
 
 If we now pursue the matter further, and give attention to the 
 villi, it will be seen that support is afforded to the view that has been 
 advanced. 
 
 It may be confidently assumed that it is through the operation of 
 protoplasmic action that the transformation is effected. For many 
 years I have been acquainted with the fact that the lacteals are well 
 charged, as above described, with milky chyle after the ingestion of 
 carbo-hydrate food ; but it did not occur to me, until recently, that it 
 was permissible to look to the villi as constituting the seat of the pi'o- 
 
250 author's conclusions. 
 
 ductlon of fat from carboliydrate matter. I had thought that the 
 most likely position for the transformation was in the liver, and, 
 doubtless, as stands in accord with general opinion, the liver possesses 
 the power of exerting more or less eifect in this direction. But, 
 looking to the liver as the special seat of transformation, there came 
 the question of how the fat reached the system. I sought for it in 
 the hepatic vein, and took into account the possibility of its reaching 
 the intestine under the form of the resinoid constituents of the bile. 
 After conducting an extended enquiry into the matter, I failed to 
 obtain evidence reconcilable with the carbohydrate matter of the 
 food being further than to a partial extent disposed of by the agency 
 of the liver. I learnt nothing satisfactory about fat reaching the 
 hepatic vein, and, with respect to the bile, the information obtained 
 failed to sufficiently give the explanation needed. 
 
 It was upwards of twenty years ago that my experiments were 
 conducted. Through the medium of a biliary fistula I collected the 
 bile, and estimated the amount of solid matter passing from the liver 
 to the intestine, under various conditions as regards iugesta. The 
 outcome of the results was quite inadequate to account for the fat 
 manifestly produced in the system from the carbohydrates of the 
 food. I saw sufficient to lead me to the opinion that some, if not all, 
 of the fat produced in the liver cells is metamorphosed into resinoid 
 biliary principles, and, in this form, transmitted to the alimentary 
 canal. Here indications presented themselves of the occurrence of 
 re-conversion into, and subsequent absorption by the villi as, fat. 
 The effect of the acid chyme escaping from the stomach is to throw 
 down the glycocholic acid of the bile when the two arrive in contact. 
 An emulsion-like product is formed, from which it has appeared to 
 me that milky chyle has arisen. Further, under certain circum- 
 stances, I have witnessed in the strictly fasting dog the lacteals 
 coming from a limited portion of the intestine to be charged with 
 milky chyle, and the interior of this limited portion to contain a 
 coloured bilious fluid, from which other parts were free. 
 
 Such was the unsettled position in which the matter formerly 
 stood. A new light has been thrown upon it by the issue of recent 
 enquiry. We look to protoplasm as the agent for effecting the trans- 
 formation. But protoplasm administers to various offices. In some 
 instances its special pui-poso is to produce secretions of diflei-eut 
 
TKANSFORMATION OF CARBOHYDRATE INTO FAT. 251 
 
 kinds, in others it may be designed to undergo metamorphosis into 
 textm-al elements endowed with particular functional attributes. 
 Assimilative power over food principles may be looked upon as con- 
 stituting its most primitive capacity, and, as regards this capacity, it 
 is possible that it does not become annulled when other functions 
 are fulfilled. Evidence, at all events, is adducible standing in sup- 
 port of this view. 
 
 The protoplasm of the cells of the villi may be regarded as speci- 
 ally intended for the performance of assimilative action. If we 
 study the villi microscopically the appearances seen after the inges- 
 tion of food and at a period of fasting are very different. In the 
 fasting state they are covered with a layer of closely set columnar 
 cells provided with nuclei and granular contents. Here and there 
 cells may be discovered containing a few fat particles, but nothing 
 beyond this in the direction of fat is discernible. The appearance 
 presented by the cells is delineated in one of the sketches on p. 253. 
 At a period of digestion numbers of cells become more or less loaded 
 with fat, as shown in the other sketch on the page. Of those which 
 become thus charged, many present a much altered form. The 
 columnar character, it is true, predominates, but the columns are 
 thicker and shorter. Often the cells are conical or pear-shaped. 
 Sometimes they are spheroidal, looking in this state very much like 
 fat-containing cells derived from the liver. Speaking of this re- 
 semblance, the cells of the liver, indeed, appear to play a supple- 
 mentary part in the formation of fat from carbohydrate to that 
 played by the cells of the villi, assimilating the carbohydrate matter 
 which escapes being assimilated in the villi, and which, as a result, 
 is permitted to reach the portal blood. It is interesting to notice that 
 both in the case of the lacteal and the vascular system a second line 
 of protoplasmic matter, consisting of the lymph cells of the absorbent 
 glands, on the one hand, and the colls of the liver on the other, has 
 to be passed before the general circulation is arrived at. 
 
 I do not see that any other conclusion is permissible than that in 
 the cells depicted, from villi of the rabbit fed upon oats, the fatty 
 matter was the product of the influence of protoplasm upon the carbo- 
 hydrate matter ingested. Looked at in their entirety, the points before 
 us stand thus. Beyond all question, as previously stated, the produc- 
 tion of fat largely takes place within the animal system from carbo- 
 
252 author's conclusions. 
 
 hydrate. After carbohydrate food the laoteals are seen to be charged 
 with milky chyle in the same manner as occurs after the direct in- 
 gestion of fat. The protoplasmic cells of the villi intervene between 
 the carbohydrate matei'ial contained in the alimentary canal and 
 fatty chyle contained in the lacteals. These protoplasmic cells, in 
 the presence of carbohydrate food, nre found to become more or less 
 loaded with fat, which finds its way into the lacteal system. Within 
 the villus there is evidently a great protoplasm-generating capacity. 
 Besides the columnar epithelial layer, which, as I have before men- 
 tioned, at the time of assimilative activity assumes, to a greater or 
 less extent, an altered character, a number of lymph or wandering 
 cells are to be seen. The two lie in close juxtaposition, and probably 
 both contribute towards rendering the villi richly provided with 
 protoplasm, propitiously placed for exerting an assimilative action on 
 the food principles prepared by digestion for service in the system. 
 
 At pp. 264, 255, 256, and 257, photo-engravings of micro-photo- 
 graphs are furnished, representing the villi in section, after fasting 
 and after the ingestion of oats. The intestine was in each case 
 subjected to the usual treatment with osmic acid for staining and 
 bringing into view the fat, and then embedded in paraffin for the 
 section cutting. Preparatory to mounting in Canada balsam the 
 sections were faintly tinted with hasmatoxyliu. After fasting, no 
 appearance of fat is presented, whilst, after the ingestion of oats, not 
 only is black stained fat visible in parts of the epithelial layer, but 
 likewise coursing along in the centre of the villus, just as is per- 
 ceptible after the direct ingestion of fat. Thus the channel of actual 
 entry of fat into the system is shown to be the same whether the fat 
 is directly ingested or, on the other hand, produced from carbo- 
 hydrate food. In the one case the protoplasm of the villi takes the 
 fat preformed; in the other it forms it from carbohydrate. In both, 
 the channel of entry is through the lacteals. 
 
TliANSFOKMAnON OF CAEBOHYDKATE INTO FAT, 253 
 
 Plioto-eiigraving from sketch showing appearances presented by cells of villi froni 
 a fasting rabbit. 
 
 Photo-engraving from sketch showing appearances presented by cells of villi froii 
 a rabbit killed four hours after having been fed with oats. 
 
author's conclusions. 
 
 Villi in section, magnified 100 diameters, from fusling rabbit. Treated with osmic 
 acid. No fat perceptible. 
 
TRANSFOKMATION OV CAKBOHYDliATE INTO FAT. 
 
 255 
 
 Villi in section, magnified 100 diameters, from rabbit killed four hours after having 
 been fed with oats. Treated with osmic acid. Blackened fat largely visible. 
 
256 
 
 AU'J'llOIt'.S CONCLUSIONS. 
 
 Point of -viUus iu seutiou, uiagnilieJ GoO diameters, from lusting rabbit. Taken 
 from a portion of tlio section represouled at p. 254. No indication of fat. 
 
TRANSFORMATION OF CAnBOHYDKATE INTO FAT, 257 
 
 Point of villus in section, magnified 600 diameters, from rabbit killed four hours 
 after having been fed witli oats. Taken from a portion of the section repre- 
 sented at p. 255. Blackened fat displayed. 
 
268 , authok's coNciX'sioxs. 
 
 The cells of the liver, as I have intimated, probably supplement 
 those of the villi in producing fat from the carbohydrate which 
 escapes disposal in the villi and reaches the portal vein as sugar. If 
 this be the case, we ought to find in the process of fattening with 
 carbohydrate food that the liver gives evidence of being involved to 
 a greater extent in the operation in question, where the villi and 
 lacteal system are less perfectly developed than under the opposite 
 condition. Xow, this happens to accord with what is actually 
 ohserved. In the bird the villi are much less highly developed than 
 they are in the mammal, and iu the process of fattening (for the 
 production of the foie gras) to which the Strasburg geese are 
 subjected the liver, as is known, attains enormous size from the 
 deposition of fat. In the mammal the case stands otherwise. 
 Many years ago I visited the slaughter-houses to which some of the 
 fat animals exhibited at the Christmas London Cattle show were 
 taken, and was struck with the healthy and fleshy-looking state of 
 the liver and the other abdominal organs. With efficiency on the 
 part of the villi, the liver would escape the tax of work that under 
 other circumstances would be thrown upon it. 
 
 I have for a long time held that what in the human subject is 
 spoken of as fatty degeneration of the liver is in reality the result of 
 conditions leading to excessive functional production of fat. Con- 
 ditions may exist attended with the ingestion of carbohydrate matter 
 beyond the capacity of the villi for dis2:)0sing of it to the usual 
 extent, and thus leave more than the ordinary amount for under- 
 going conversion into fat by the agency of the liver. 
 
 As regards the mode of transformation, by protoplasmic action, of 
 carbohydrate into fat, I consider that it may be reasonably surmised 
 that the process is not a direct one, but one in which the production 
 of proteid plays an intermediate part. It has been pointed out 
 (p. 2-10) that in the transmutation of carbohydrate matter to a lower 
 form of hydration in the vegetable organism, as, for instance, in the 
 deposition of fabric cellulose and storage starch, the weight of 
 evidence and probability is in the direction of its being effected by 
 entering, in the first instance, into the constitution of the proteid of 
 the protoplasm that is instrumental in bringing about the change, 
 and then being deposited in the altered form. Similarly, the proto- 
 plasmic matter of the cells of the villi may first lead to the incorpora- 
 
ti;ansfoi:.mati(ix of cakiioiiydkate into fat. 259 
 
 tion of the cai-bohydriite i.ito proteid, from which, by cleavage, the 
 fat may be afterwards thrown off. 
 
 If we here pause for a momeni: to look at what is observed to occur 
 elsewhere, it will be seen that there is nothing irrational in the view 
 that has been put forward. 
 
 According to the description that is given in physiological works 
 of the secretion of milk by the mammary gland, the alveoli are lined 
 with cells consisting of growing protoplasm, which undergoes meta- 
 bolic change so as to give rise to the appearance within its substance 
 of fat globules of various sizes that become discharged, and constitute 
 the fatty portion of the milk. Protoplasm exists to begin with, and 
 from this the elements of the milk are derived apparently, it may be 
 stated, by a process of splitting up. The cleavage of proteid may 
 give rise not only to the fat but likewise to the lactin and casein, and 
 in support of casein constituting a product, from the antecedent of 
 which carbohydrate has been cleaved, we have the fact, as I men- 
 tioned (p. .32) when speaking of the glucoside constitution of proteid 
 matter, that only an insignificant amount of cleavage carbohydrate is 
 obtainable from it by chemical means, compared with what is obtain- 
 able from albumin and other proteids. 
 
 Again, the same kind of description is employed for representing the 
 deposition of fat in the development of the adipose tissue of the body. 
 The deposition takes place in the cells belonging to the connective 
 tissue. These multiply and become charged with oil globules, which 
 grow larger and coalesce, until ultimately the cell consists of one large 
 spherical oil globule, the protoplasmic remains of the cell forming 
 a thin capsule around it. The protoplasm of the cell thus visibly 
 becomes replaced by fat, which we are driven to look upon as split off 
 from the pre-existing proteid substance. 
 
 In the peculiar disease known as myxoedema, which is attended 
 with an undue accumulation of connective tissue conspicuously 
 infiltrated with a redundance of its proteid accompaniment — mucin, 
 the idea, in view of the doctrine I am advocating, forces itself upon 
 the mind that the condition may be due to an imperfect performance 
 of proteid cleavage and liberation of fat. The province of protoplasm 
 is to construct, whilst the effect of ferment action is to split up. 
 The redundance of connective tissue and mucin may be referable to 
 default existing in connection with the latter process. It may be, in the 
 
2G0 author's coxclusions. 
 
 disease, that there is a want or deficiency of the proper ferment for 
 splitting oif fat from proteid, and that the curative eifect of the 
 thyroid extract treatment is attributable to the want being met by 
 introducing into the system the ferment derived from an external 
 source. 
 
 In the fatty degeneration of muscle it may further be taken that 
 an allied cleavage of fat from proteid occurs. Although the special 
 object of the protojslasm may not be, as in the instances that 
 have been dealt with, to effect the formation of fat, the proteid — 
 indeed, the same may be said of tissue proteid anywhere existing — 
 may undergo dissociation with the liberation of fat when conditions 
 deviating from those which tend to the maintenance of a state of 
 integrity prevail. 
 
 From the train of reasoning befoi'e adduced (p. 24.5) the con- 
 clusion is deducible that the actual source of all fat is the primordial 
 carbohydrate produced by the chlorophyll corpuscles of the vegetable 
 kingdom actuated by the power derived from the sun. Starting 
 with this carbohydrate, the operation of living protoplasm is needed 
 for its conversion into fat, and the first step of the process pre- 
 sumptively consists of incorporation into proteid. The step to follow 
 will be one of cleavage, and this may ensue either at once, as, for 
 example, in the case of the villi, or subsequently, as in the case of 
 the mammary gland, the growth of adipose tissue, and the fatty 
 degeneration of muscular and other structures. 
 
 There may be, it is true, changes taking place within the living 
 system of an ordinary chemical nature, but the two mainsprings of 
 power determining the chemical metamorphoses of life are proto- 
 plasmic and ferment actions. The eifects produced by these are 
 directly opposed. Whilst we witness as the result of the operation of 
 the one a synthesising or constructive effect, the effect of the other is 
 to dissever or split up. It is, doubtless, upon a delicately-adjusted 
 balance of these two operations that the play of changes belonging to 
 life depends. Assuming carbohydrate to have been appropriated by 
 the instrumentality of protoplasmic action to the construction of 
 proteid, we have a body to deal with from which either carbohydrate 
 or fat may be subsequently evolved according to the surrounding 
 determining conditions. The blood supply (embracing the state of 
 the blood which is influenced by that of the arteries through their 
 
TKAXSFOKJIATION OF CAKBOIIYDUATE INTO FAT. 2G1 
 
 musctilar coat governed by the nervous system) probably constitutes 
 a gi-eat factor in the determination of the result. At all events, con- 
 siderations, it will be seen, can be adduced, g'iving support to this 
 conjecture. 
 
 Observation, for instance, sbows that the conditions conducive to 
 fat deposition are sluggish circulation, deficient blood supply, and 
 deficiency of the red corpuscular element of the blood, all of which 
 tend to produce a deficiently-oxygenated state. The fattener of 
 animals knows that, with a given amount of fattening food, his object 
 is more speedily attained by keeping the animal in a state of quies- 
 cence, and, further, in a darkened place, the effect of which is to 
 favour escajJB from the temporary excitations of the vascular system 
 produced by nerve action. The more vegetative the life of the animal, 
 to a greater extent does it become a fruitful fat producer. Both func- 
 tional fat production from carbohydrate and fat cleavage from tissue 
 proteid are favoured. 
 
 In illustration of the effect of deficient blood supply, and also of 
 deficiency of the red corpuscular element of the blood, in pi-omoting 
 the cleavage of fat from proteid, 1 may refer to the fatty degeneration 
 of the muscular fibres of the heart which is observed as an accom- 
 paniment of ossification and other obstructive conditions affecting the 
 coronary arteries, and also of the morbid state known as idiopathic or 
 pernicious anoemia. The occurrence of fatty degeneration — proteid 
 fat liberation — it may be added, under the circumstances named, is 
 nothing more than a phenomenon standing in harmony with a recog- 
 nised pathological principle applicable to the tissues generally. 
 
 In advanced diabetes, proteid cleavage with the liberation of sugar, 
 instead of fat as in fatty degeneration, occurs, and observation shows 
 that an opposite kind of blood influence prevails. 
 
 In mild forms of the affection, and in the early stage of the grave 
 class of case, the tissues do not suffer when the disease is held under 
 by appropriate dietetic management. Under these circumstances, 
 the only fault existing is a defective application or assimilation of the 
 cai'bohydrate matter ingested. That this is the case is proved by the 
 train of reasoning I will proceed to set forth. 
 
 The question presented for solution is whether protoplasmic assimi- 
 lative action is at fault, or whether assimilated carbohydrate is brought 
 back into sugar by the operation of undue ferment influence. As the 
 
262 AUTITOU's CONCLUSIONS. 
 
 tissues, under tlie circumstances named, supply no evidence of being 
 implicated, the exercise of the undue ferment inQuence, if it exist, 
 must be located in the liver ; and, as is known, we have here trans- 
 muted sugar under the form of glycogen to deal with which, if 
 re- trans formed into sugar by ferment action, would account for the 
 phenomenon we are considering. Now, should the result be attribut- 
 able to ferment action, sugar ought to be discharged with the urine 
 after the ingestion of limited as well as of larger amounts of carbo- 
 hydrate. The ferment would operate alike in each case, and lead to 
 sugar production equal to the extent of its power of action. But, in 
 the cases in question, carbohydrate can be ingested up to a cei'tain 
 amount (the amount varying with, and remaining steady in, the 
 individual case) without being attended with the elimination of sugar. 
 There is the capacity of disposing of ingested carbohydrate matter 
 within the system up to a certain point without leading to its run- 
 ning off as sugar. The only difference between such a case and the 
 healthy state is that the capacity is more limited in the one than it is 
 in the other, and we ai'e driven to conclude that the fault must con- 
 sist of an impairment of the power possessed by the system of 
 appropriating the carbohydrate, and preventing its escape from the 
 body as sugar. 
 
 I hold, as enunciated in this work, that protoplasmic action is the 
 agency by which the appropriation of carbohydrate matter is effected, 
 and that the agents of appropriation are the cells of the villi and of 
 the liver. Under normal ciixumstances, carbohydrate is not allowed 
 to pass these lines of stoppage. Conditions leading to its doing so 
 occasion saccharine urine, which stands proportionate in extent to 
 the amount of carbohydrate that escapes arrest, and is thus per- 
 mitted to reach the general circulation. All the facts disclosed hy 
 experience bearing upon diabetes stand in conformity with this 
 assertion . 
 
 I have said that we must look to deficient protoplasmic action as 
 the source of the sugar which passes off as waste material from in- 
 gested carbohydi-ate. It cannot be conceived, however, that the 
 error is due to the protoplasm itself. This, it may be considered, is 
 endowed with an inherent power which, as long as it is in a living 
 state, it retains. For the due exercise, however, of this power proper 
 sui'rounding conditions are needed. The state of the blood I regard 
 
TRANSFOKXrATIOX OF CUiUOIIYDRATES INTO FAT. 2Go 
 
 as a most important factor in relation to this matter. An unduly 
 oxygenated state can be demonstrated to constitute a source of 
 saccharine urine ; and, it is interestino- to note, that carbonic oxide 
 and also, it is to be said, the nitrites — agents which, in each case, pro- 
 duce analogous compounds with haemoglobin to the oxygen com- 
 pound, oxyhsemoglobin — lead to the same result. Now, enough 
 evidence exists to show that an unduly oxygenated condition of the 
 blood, arising from vasomotor paralysis, and explicable by the in- 
 creased transit through the capillaries failing to permit de-ai-terialisa- 
 tion to the ordinary extent to occur, actually exists in connection 
 with diabetes. 
 
 A vasomotor paralysis implicating only the vessels of the chylo- 
 poietic viscera may stand at the foundation of the form of diabetes 
 limited to defective assimilation of ingested carbohydrate. The red, 
 or raw meat, appearance of the tongue, and it may be of the whole 
 interior of the mouth, including the fauces and pharynx, that is some- 
 times seen, affords evidence of vasomotor paralysis of a more 
 extended kind, and in harmony constitutes, as experience shows, 
 an indication of severity. In cases occurring in persons of ad- 
 vanced years, the disposition exists for the complaint to be confined 
 to a defective appropriation of ingested carbohydrate. In cases, on 
 the other hand, occui-ring amongst young persons, whilst, as a rule, 
 defective appropriation of ingested carbohydrate constitutes the only 
 condition existing at first, the affection progresses, and, in the course 
 of time, sugar is eliminated beyond what can be accounted for by the 
 food, and is evidently in part derived from the tissues of the body. 
 The condition which at one time only leads to a manifestation of 
 defective assimilation subsequently, on attaining a more advanced 
 stage, gives rise to dissolution of constructed proteid with the 
 cleavage of sugar, and thus produces the more intensified form of 
 disease that becomes developed. 
 
 It will be observed fi'om what has been said that the cleavage of 
 fat and the cleavage of sugar from tissue proteids are associated 
 with opposite states of the contents of the vascular system. An 
 under-oxygenated state is noticed in association with the one, an 
 over-oxygenated state in association with the other. Probably the 
 processes of fat and carbohydrate cleavage are always being carried 
 on to a certain extent, the carbohydrate cleavage resulting under 
 
264 author's conclusions. 
 
 natural circumstances in glycogen and not sugar, and accounting 
 for the glycogen met with in various textures. 
 
 Reading nature by the light of the evidence that has been set 
 forth, we learn that, as a result of the operations of life, carbohydrate 
 matter becomes (1) transmuted to a lower state of hydration, (2) ap- 
 plied to the production of proteid, and (3) transformed into fat. 
 Some other changes of minor import contributing to subsidiary 
 offices in the economy may take place, but I have no misgiving about 
 carbohydrate matter passing, in the main, in the directions named 
 for application to the pui'poses of life. Observers have hitherto been 
 looking for the acquii-ement of knowledge concerning the manner in 
 which carbohydrate matter becomes disposed of in the animal system 
 by the prosecution of research in the opposite line of inquiry. Fruit- 
 less results have attended, and, I am of opinion, are not likely to do 
 otherwise than continue to attend such efforts. From an abyss of 
 darkness, constituting the outcome of research conducted in the 
 direction of change produced by ferment action and chemical agents, 
 we are led, by research applied in the direction of protoplasmic action, 
 to a clear and intelligible position. Harmony exists throughout, and 
 the whole thing can be epitomised so as to lie in a nutshell. By proto- 
 plasmic action carbohydrate matter, as observation teaches us, is dis- 
 posed of in a certain manner. If not disposed of in this manner, it 
 escapes from the system as useless material, producing the condition 
 belonoins' to diabetes. 
 
I N 13 E X. 
 
 PAGE 
 
 Absorption of sugar from stomach 83 
 
 Achroodextrin 11 
 
 Acrose, a, an artificially synthesised six carbon atom sugar . , 5 
 
 Acid, citric, cane-sugar inverting power of, at body temperature 08 
 
 emjjloyment of, for inversion of cane-sugar 92 — 93, 108 
 
 glycuronic, asserted presence in urine after chloroform 163 
 
 ^-^ hydrochloric, cane-sugar inverting power of, at body temperature 98 
 
 lactic, probable formation of, from glucose in alimentary canal 100 
 
 probable formation of, from lactose in alimentary canal 99 
 
 sulphuric, action of, on carbohydrates 92 
 
 — relative effects of 2 per cent, and 10 per cent, strengths upon 
 
 cleavage carbohydrate 213 
 
 Acids, action of, on cane-sugar 92, 98 
 
 effect on action of amylolytic ferments 83, 85 — 87 
 
 Albumin, egg, cleavage experiments on 31 
 
 ■ preparation and purification for potash cleavage experiments . . 33 — 34 
 
 ■ — preparation and purification for treatment to obtain cleavage sugar 
 
 with sulphuric acid 44 
 
 Alcohol-coagidation does not destroy sugar-producing ferment of liver . . 147 — 154 
 Alcohol, employment in process of glycogen (amylose carbohydrate) exti'ac- 
 
 tion and estimation (33 
 
 strength required for precipitation of prot«id-eleavage product 33 
 
 use of, in extracting sugar 58 — 62 
 
 Ammonia, interference of, with employment of ITehling's solution 178 
 
 principle of action of, in the ammoniated cupric test 71 — 80 
 
 vitiating influence of, in gravimetric sugar determinations 70 
 
 Ammoniated cupric test equally applicable to fresh and decomposing pro- 
 ducts . . , 173 
 
 mode of titration with 75 — 78 
 
 precautions in use of 72, 77 — 78 
 
 precision attainable with 78 — 80 
 
 quantitative determination of sugar by 71 — 80 
 
 reliability shown by close accord in duplicate analyses and 
 
 with the results yielded by the gravimetric process 79 
 
 solution, composition and preparation of 71 — 74 
 
 self-preservative power of 71 
 
 sugar value of 73 — 74 
 
 standardisation of 74 
 
 Amygdalin, example of nitrogenous glucoside 27 
 
 Amylodextriu 11 
 
26G INDEX. 
 
 PAOK 
 
 Araylodextrin, constitution ol' 45 
 
 Amyloid substance, eraplojment of tci-iii 212 
 
 Amylose carbohydrate, employment ol' term 213 
 
 in blood and tissues 215—220 
 
 Amyloses, general description of C — 12 
 
 Analytical procedure for recognition and estimation of carboliyilratos in 
 
 animal products 58— 80 
 
 Animal, cold-blooded, sugar in liver of 110 — 143 
 
 • charcoal, employment of, for decolorising satcliarine products 180 
 
 food as a source of glycogen 1 18 — 121 
 
 both free and cleavage sugar derived from 118 — 121 
 
 sugar in portal blood after 104 
 
 gum 10 
 
 resemblance of proteid-cleavage product to. . , , 35, 41 
 
 the eai'bohydrate from the glucoside mucin 27 
 
 Apparatus for sugar titration, description and figure of 75—76 
 
 Arabinose, a five carbon atom sugar 1 
 
 Asparagin, conjugation with carbohydrate to form protcid , . . 239 
 
 participation in synthesis of proteid in plant 54—55 
 
 Autoclave, employment for aqueous extraction of glycogen from liver 124 
 
 employment in analysis 67 
 
 Beef tea, presence of sugar in 118 — 119 
 
 Bernard, alleged tolerating capacity of blood for sugar 187 — 193 
 
 discovery of glycogen by 211 
 
 glycogenic theory propounded by Ill, 112, 113 
 
 on amoxint of sugar in blood 162 — 163 
 
 on disappearance of sugar from drawn blood 171 
 
 on influence of body temperature on amount of sugar in liver after 
 
 death 141 
 
 statement about sugar in arterial and venous blood 166 
 
 Berthelot on artificial glucosides 53 
 
 Bile, fat from resinoid matter of 250 
 
 influence of, in digestion 84 
 
 Blood after withdrawal, in relation to sugar 171 
 
 alleged tolerating capacity for sugar 187 — 193 
 
 amount of sugar in 158 — 165 
 
 analysis for sugar 150, 161 
 
 and tissues in relation to amylose carbohydrate 215 — 220 
 
 comparison of arterial and venous, in relation to sugar 166 — 171 
 
 evidence given by, of sugar-arresting action of liver 109 — 112 
 
 examination of, for carbohydrate 59 — 64 
 
 facts connected with, refute glycogenic doctrine 223— 225 
 
 hepatic venous, condition of, in relation to sugar 110 — 111 
 
 increases sugar production in washed liver 147 
 
 influence of, on sugar production in liver after death 137 
 
 in relation to sugar 157 — 177 
 
 Lepine's theory of glycolysis in 176 — 177 
 
 nature of sugar in 157 — 158 
 
INDEX. 267 
 
 PAGE 
 
 Blood of general circulation, amount of sugar in 161 
 
 not Tariable as portal, in relation to food 112 
 
 standard amount of sugar in 101 
 
 uninfluenced by ingestion of carbohydrate 103 
 
 of liepatic reins, saccharine state found after death one of main sup- 
 ports of glycogenic theory ■...,... 136 
 
 portal, after animal food gives evidence of absorption of sugar .... 120 — 121 
 
 amount of sugar in 101 — 1U8 
 
 and genei-al, relative amount of sugar in Ill 
 
 carbohydrates from ingestion traced to SI 
 
 nature of sugar in 158 
 
 product of starch digestion in 89 — 90 
 
 supports proteid formation from carbohydrates 212 
 
 the carrier of ingested carbohydrate to the liver 117 
 
 Tariable condition of, as regards sugar in relation to food not 
 
 transmitted to blood of general circulation 112 
 
 post-mortem not to be taken, as regards sugar, as representative of 
 
 ante-mortem state 160 — 161 
 
 precautions requisite in collection for analysis 110, 160, 163 — 165 
 
 state of, influencing fat and sugar production 260 — 261 
 
 Boiling, method for preventing ^os<-»ior/e»! ferment action in liver .... 134 — 135 
 
 Brain, sugar in 201 
 
 Brown and Morris on the dextrins 11 
 
 Briicke's process for separation of sugar from normal urine 179 — 180 
 
 Brunner, glands of . ■ °7 
 
 Cane sugar, absence of cupric oxide reducing power 92 — 93 
 
 an illustration of dehydrating action 21 
 
 chemistry and properties of 12 — 13 
 
 : citric acid the best agent for inversion for quantitative determina- 
 tion ^7 
 
 constitution of, 44 
 
 digestion of • "1 98 
 
 estimation of, in presence of other carbohydrates 93 
 
 form of sugar in portal blood after ingestion of 98 — 99, 108 
 
 inversion, interfering action of sodium sulphate 108 
 
 of, by acids 92, 98 
 
 inverted by dilute acids at body temperature 98 
 
 by ferment in stomach (to small extent) and intestinal walls 94 — 96 
 
 portal blood after ingestion of 107 — 108 
 
 relation to optical rotation 12 — 13 
 
 uninfluenced by salivary and pancreatic secretions 93 
 
 '. — use of, in standardising ammoniated cupric test 74 — 75 
 
 Carbohydrate, amylose, analytical procedure for examination of animal 
 
 products for ""^ "'» 
 
 and fat mutually convertible 247 
 
 appUcatioD to proteid formation 233, 239 — 245 
 
 chemical constitution of o 
 
 dehydration by protoplasmic action S 
 
268 INDEX. 
 
 PAGE 
 
 Carboliydrate, deposition from pvoteid in plant 55 — 57 
 
 destination of, in animal system 232— 264 
 
 effects of protoplasmic action upon 233 
 
 food a source of fat 248 
 
 • sugar in portal blood after 81, 105 — 108 
 
 genesis of 1 — 4 
 
 ingested, a source of glycogen 113 — 117 
 
 incorporation in construction of proteid 53 — 55 
 
 — ^ mode of transformation into fat by protoplasmic action 258 
 
 primordial source of all carbon compounds of nature 245 
 
 reserve of plants, on illustration of dehydrating action 21 
 
 transmutations in living plant 25 — 26 
 
 universal distribution of 233 
 
 used in formation of proteid and fat by cells of villi 121 
 
 Carbohydrates, artificial synthesis of 5 
 
 — — chemical characters and relations of 5 — 16 
 
 classification of 6 
 
 ^^— elementary composition of 1 
 
 general formula for 1 
 
 how naturally disposed of in the animal system 221 — 264 
 
 ingested, liver in relation to sugar from 101) — 131 
 
 portal blood in relation to 101 — 108 
 
 sense in which term used 1 
 
 stopped from reaching general circulation by cells of villi and liver. . . , 262 
 
 synthetic formation in plant 2 
 
 transmutation of 1 8 — 26 
 
 in relation to operations of life 22 — 26 
 
 with decreased hydration 19 — 22 
 
 with increased hydration 18 — 19 
 
 varied number of carbon atoms in molecule of 1 
 
 vegetable kingdom the source of 1 
 
 Carbonic acid, source of cai-bon of carbohydrate 2 
 
 oxide inhalation leads to production of glycosuria 145 
 
 Casein, a suggested cleavage-product from proteid 32, 245 
 
 ' cleavage experiments on 32 
 
 Cells of liver, fat formers 251 
 
 ' of villi, fat formers « • 251 
 
 photo-engraving of, showing appearance of, after fasting . . 253 
 
 after ingestion of oats 253 
 
 Cellulose, behaviour of, with sulphuric acid 7 
 
 — — chemistry and properties of G — 8 
 
 deposition in plant " '* 
 
 dissolving power of fungi upon 91 
 
 formation by yeast cells 3 
 
 in relation to digestion 90—91 
 
 in yeast, an illustration of dehydrating action 21 
 
 resistance of, to solvents 90 — 91 
 
 ultimate transmutation product in plant 2.14 
 
 Chlorophyll corpuscles, formation of starch by 55—56 
 
INDEX. 269 
 
 PAGE 
 
 Chlorophyll corpuscles, seat of primary carbohydrate formation 4 
 
 power of flidng carbon 2 
 
 Chyle, milky, after carbohydrate food 248 
 
 Chyme, neutralisation of, by alkali of bile, &,c 84 
 
 Citric acid, effect of, on lirer-ferment 155 
 
 use of, in inversion of cane-sugar for quantitative determination . 74 
 
 Cleavage-carbohydrate and glycogen from various structures 211 — 220 
 
 . effects of different strengths of sulphuric acid upon 213 
 
 ^-^ of proteid, origin of carbohydrate by 3 — 4 
 
 sugar from digestion of animal food 119 — 120 
 
 Cold-blooded animal, sugar in liver of 140 — 143 
 
 Colloidal properties of starch 81 
 
 Conversion of amyloses and saccharoses into glucose by sulphuric acid, time 
 
 required for G6— 67 
 
 Copper compound from potash proteid-cleavage product 35, 42 — 43 
 
 Cupric oxide reducing power not possessed by cane sugar 92 — 93 
 
 of sugar of portal blood 102 
 
 # 
 Decomposition, effect upon disappearance of sugar from drawn blood .... 173, 176 
 
 Dehydration changes the result of action of living matter 18,19 — 22 
 
 Dextrin, chemistry and properties of 10 — 12 
 
 example of artificially induced dehydration 20 
 
 probable nature of action giving rise to 10 — 11 
 
 production of, in pancreatic digestion of starch 84 
 
 source of 10 — 11 
 
 Dextrins, production of, in process of starch digestion 82 
 
 Dextrose, chemistry and properties of , . 15— 16 
 
 convertible into hevulose 52 
 
 different optical varieties of 52 
 
 sources of 15 
 
 Diabetes, a faulty disposal of carboliydrate matter 222 
 
 association with cleavage of sugar from proteid 229 
 
 due to defective assimilation of carbohydrate 229 
 
 glucose the form of sugar eliminated after ingestion of lactose 99 
 
 inhibitory action of liver 112 
 
 in relation to effects of ferment and protoplasmic actions 262 
 
 • — — mild form, defective assimilation of carbohydrate only 201 
 
 . . toleration to some extent of carbohydrate food 262 
 
 production of sugar from tissues in 263 
 
 • rationale of dietetic management of 228 — 232 
 
 relation of sugar in urine to that in blood 191 — 193 
 
 . to vaso-motor paralysis 263 
 
 severe form, sugar in part derived from proteid-cleavage 261 
 
 teachings of, refute glycogenic doctrine and point to mode of disposal 
 
 of carbohydrate matter 227 — 232 
 
 Diastase, example of unorganised ferment (amylolytic) 19 
 
 Diet, regulation of, in diabetes 228—232 
 
 Digestion, cleavage-sugar from proteid matter produced in 119 — 120 
 
 of cane sugar 91 — 99 
 
270 INDEX. 
 
 PAGE 
 
 Digestion of cellulose ^^ ^1 
 
 of lactose ^" 
 
 of starch 81 — 00 
 
 nece35<ar}' for its absorption S2 
 
 Egg, sugar in 206 — 210 
 
 Enzyme, see ferments, unorganized. 
 
 Erythrodextrin 11 
 
 Erjthrose, a 4-carbon atom sugar 1 
 
 Fasting, sugar in portal blood after 103 
 
 Fat and carboliydrate mutually eourertible 247 
 
 as seen in villi in section after ingestion of oats, photo-engravings of 
 
 micro-photographs 255, 257 
 
 • ■ derived from carbohydrate food 348 
 
 formation from carbohydrate 233, 245 
 
 by cells of villi 121 
 
 ■ iu oily seeds ^ . . 247 
 
 in villi from carbohydrates of food 248 
 
 from carbohydrate by protoplasmic cells of villi 252 
 
 mode of production from carbohydrate by protoplasmic action 258 
 
 of adipose tissue, cleavage from proteid 259 
 
 of milk, a cleavage product from proteid 245 
 
 origin in yeast from carbohydrate 24G 
 
 production of, from carbohydrate by cells of liver 258 
 
 Fatty degeneration of liver a result of excessive fat formation 258 
 
 of muscle fat cleavage from proteid 260 
 
 Fehling's solution, composition of 68 
 
 author's modification of 68 
 
 Ferment action attended with increase of hydration ■ 18 — 19 
 
 influence upon cellulose 19 
 
 in relation to operations of life 22 — 24 
 
 nature of 18 — 19 
 
 proteid-cleavage sugar produced by 49 — 51 
 
 ■ amyloly tic, in certain digestive secretions. 82 
 
 ■ and protoplasmic actions opposed in their effects 260 
 
 reciprocal play of 24 — 26 
 
 ■ • cane sugar inverting, not destroyed by alcohol 95 — 96 
 
 • • — — contained in stomach (to small extent) and intestinal 
 
 walls 94—96 
 
 glucose-forming, in intestine 87 — 89 
 
 of liver, glucose-forming capacity of 146 
 
 pancreatic, experiments witii 84 
 
 (sugar-forming) of liver , 133 — 140 
 
 analogous position to fibrin ferment of blood 146 
 
 Ferments, action of, on cellulose 90 — 91 
 
 • ■ amylolytic 19, 22 
 
 peptonising or proteolytic, in animal and in plant 22 — 23 
 
 production in seeds and buds 25 — 26 
 
INDEX. 271 
 
 PAGE 
 
 Ferments, unorganised 19 
 
 Fermentability, dirersity presented by the various sugars 52 
 
 Fermentation, acetic acid 18 
 
 alcoholic 18 
 
 distinct from ferment action 18 — 10 
 
 lactic acid 18 
 
 occurrence with sugar of normal urine 181 
 
 negative behaviour of proteid-cleavage-sugar 10 — -11 
 
 putrefactive 18 
 
 Fibrin, cleavage experiments on 32 
 
 Filter-paper, danger of using, in dealing with carbohydrates 63, 21-1 
 
 Fischer, E., on optical activity of substances 41 
 
 ' varieties of sugar 52 
 
 • on recovering sugar from an osazone 16, 49 
 
 on tlie phenylhydrazine reaction of sugars 17 
 
 work on synthesis of sugars 5 
 
 Foie gras, result of fat formation from carbohydrate food 247, 258 
 
 Food, carbohydrate, influence on amount of glycogen in liver 127 
 
 Freezing, method of checking post mortem transformation of glycogen. . . 125, 128, 
 
 129, 134—140 
 Frog, illustrating influence of body-temperature at death on amount of sugar 
 
 "in liver 141 
 
 liver rich in glycogen i 131 
 
 Fungi, cellulose-dissolving power of 91 
 
 occurrence of glycogen in 9 — 10, 235 
 
 Galactose, chemistry and properties of 16 
 
 production from lactose 1*^ 
 
 Gastric juice, efTect of, on starch digestion ^^3 
 
 Gelatin, cleavage experiments on 3L 
 
 Generative organs of Fish and Crustacea, sugar in 205 
 
 Genesis of carbohydrate 1 — 4 
 
 Glass-wool, use of, for filtration • , 62, 63—64 
 
 Glucosan, example of artiBcially induced dehydration -0 
 
 formation from artificial glucosides ■ 53 
 
 dextrose 1" 
 
 Qlucosazone, crystalline character of 17 
 
 from sugar of liver taken in ordinary way after death, photo-engraving 
 
 of 140 
 
 Glucose, carbohydrate matter estimated as 127, 148 
 
 escape with urine after injection into circulation 187 190 
 
 form in which ingested cane sugar reaches portal blood 99, 108 
 
 -forming capacity of liver-ferment 1™ 
 
 -forming ferment of intestine ^7 8 J 
 
 . ■ form of sugar in liver after post-mortem change, but not previously .. 138 
 
 in blood of general circulation 1^7 
 
 found in urine aft«r excessive ingestion of cane sugar 11" 
 
 in urine of diabetic after ingestion of lactose •■'•' 
 
 not changed by digestion 100 
 
272 INDEX. 
 
 PA&E 
 GUiieose uot to any large extent pro.luccl from starL^li witliin alimentary 
 
 canal 89 
 
 ' subsidiary production of, by action of saliva on starch 83 
 
 the kind of sugar in the egg 20G— 207 
 
 the sugar usually eliminated in diabetes 239 
 
 Q-lueoses, general description of 15— IB 
 
 ■ optically inactive, in sugar cane 41 
 
 Grlucosone-like body obtained in process for recovering cleavage sugar from 
 
 its osazone 47 
 
 Glueoside constitution of proteid matter - 27 — 57 
 
 ■ — bearings of, in relation to diabetes 229 
 
 — physiological significance of 240 
 
 illustration of cleavage 3 
 
 Glucosides 27 — 57 
 
 artificial 5"^ 
 
 — — physiological interest and importance of 2S 
 
 Gluten from wheat flour, cleavage experiments on 31 
 
 G lycerose, a 3-carbon atom suga r 1 
 
 Glycogen, amount of, in liver after animal food 114 
 
 after diet rich in carbohydrates 114 — 117 
 
 under different conditions and in different animals . 125 — 131 
 
 ^-^ and cleavage-carbohydrate, process for estimation of 211 — 214 
 
 and proteid-cleavage carbohydrate from various structures 211 — 220 
 
 animal food as a source of 118—121 
 
 a transmutation product in animal • 235 
 
 chemistry and properties of 9 — 10 
 
 ■ difficulty of complete extraction by water from liver 122 — 125 
 
 diminution compared with sugar production in liver-ferment experi- 
 ments ., 143 
 
 discovery of 113, 211 
 
 estimated in analysis as glucose 127 
 
 existence in yeast and other fungi 9 — 10 
 
 formation by yeast cells " 
 
 general relations as a constituent of liver 122 — 131 
 
 ingested carbohydrate matter a aource of 113 
 
 in liver an illustration of dehydrating action 22 
 
 in liver from excess of carbohydrate food 244 
 
 in yeast an illustration of dehydrating action 21 
 
 old method of estimation of 114 
 
 physiologically a misnomer 9 
 
 post-mortem transformation of, in liver 128 
 
 process for extraction and estimation of 2S, 63 — G-t 
 
 rapid post-moi-tem transformation of, in liver 125 — 126 
 
 recognition in liver-cells 122 
 
 representative of starch in animal kingdom 81 
 
 the term physiologically a misnomer 212 
 
 Glycogenic doctrine, refutation of 22 1 — 227 
 
 theory (Bernard's), fallacy at the foundation of Ill 
 
 initiation of 112—113 
 
PAGE 
 
 G-lycolose, a 2-cai'bon atom sugar 1 
 
 Glycoljsis in blood, Lepine's theory 176 — 177 
 
 Grape sugar, see Dextrose. 
 
 GraTimetrie process of sugar estimation 69 — 70 
 
 Gummose, sugar from Lnndwehr's animal gum 27 
 
 Horse, tissues rieli in glycogen 130 — 131 
 
 Hy drazones 17 
 
 Hydi'olytic action of acids and ferments 18 — 19 
 
 Incubation, effect on sugar of egg 207 — 210 
 
 Intestinal juice, see succus entericus 87 
 
 Intestine, cane sugar inverting power possessed by 94 — 96 
 
 exceptional state in ruminant 94, 96 
 
 of ruminant, small cane sugar iuTerting power of 94, 96 
 
 Inversion of cane-sugar by acids 92, 98 
 
 Invertin, existence in yeast 21 
 
 example of unorganised ferment 19 
 
 Invert sugar, composed of dextrose and laerulose 13 
 
 formation from cane sugar 13,92 
 
 Kidney, sugar belonging to 201 
 
 sugar elimination by 1 62 
 
 Lacteals, milky injection of, after carbohydrate food 248 
 
 Lactose, action of acetic and citric acids on 13 — 15 
 
 chemistry and properties of 13 — 15 
 
 constitution of 44 
 
 conversion by sulphuric acid into dextrose and galactdsc 15 
 
 cuprie oxide reducing power of 13 
 
 digestion of 99 
 
 • glucose in urine of diabetic after ingestion of 99 
 
 osazones from, under varied conditions 14, 
 
 possibly a proteid-clenvage product 32, 245 
 
 • probably partly converted into lactic acid in alimentary canal 9y 
 
 time required for conversion effected by sulphuric acid 67 
 
 Lievulosan, example of artificially-induced dehydration 20 
 
 formation from lavulose 10 
 
 Lajvulose, chemistry and properties of l(i 
 
 different optical varieties of 52 
 
 escape with urine after injection into circulation , IbO — 191 
 
 — — sources of 16 
 
 Landwehr, on mucin and animal gum 27 
 
 Landwehr's " animal gum," copper compound of 35 
 
 Lieberkiihn, glands of, function of 87 
 
 liiebig's classification of foods as regards carbohydrates untoiiablo 244 
 
 Light, influence on carbohydrate formation 4 
 
 Liver, amount and nature of sugar in, at moment of death and afterwords 136— 1;-19 
 
274 INDEX. 
 
 PAGE 
 
 liiver an agent, for carbohydrate transmutation 235 
 
 cells supplement cells of villi in production of fat from carbohydrate . . 258 
 
 fat formation in , 249 
 
 Liver-ferment, observations on, after alcohol coagulation 150, 15i — 156 
 
 possesses a glucose-forming capacity 146 
 
 Liver, in different animnls, in relation to glycogen 127 — 131 
 
 ingested carbohydrate, a source of the glycogen in 113 — 117 
 
 in relation to sugar 132 — 156 
 
 in relation to sugar from ingested carbohydrates 109 — 131 
 
 ■ in same position as other structures in relation to amount of sugar 
 
 present 144 
 
 general relations of glycogen in 122 — 131 
 
 not, as asserted, the seat of production of sugar from proteid of animal 
 
 food 121 
 
 of cold-blooded animal, amount and natui-e of sugar in 140 — 143 
 
 post-mortem production of sugar in 133 — 140 
 
 • production of fat by cells of 258 
 
 saccharine state found after death one of main supports of Ci-lycogenic 
 
 Theory 136 
 
 so-called fatty degeneration of, a result of excessive fat formation .... 258 
 
 sugar-arresting function of : evidence of afforded by the blood 109 — 112 
 
 evidence of afforded by the organ itself 112 — 118 
 
 sugar-fonning ferment of 133 — 140 
 
 Lung, sugar in 2l'2— 203 
 
 Liver-substance, sugar production in, after coagulation by alcohol 147 — 154 
 
 true state of, stands against glycogenic doctrine 223 
 
 • washed free from blood, sugar production in 146 — 147 
 
 Living matter, special power possessed by 24 
 
 Maltodextrin 11 
 
 constitution of 45 
 
 Maltose, chemistry and properties of 12 
 
 constitution of 44 
 
 ■ conversion by sulphuric acid into dextrose 12 
 
 — — main end product of action of saliva on starch 82 
 
 portal blood after ingestion of 107 
 
 production of, in pancreatic digestion of starch 84 
 
 product of starch transformation 11, 12 
 
 time required for conversiou by sulphuric acid 66 — 67 
 
 Melting points of cleavage sugar osazone, galactosazone, and glucosazone. ... 48 
 Milk sugar, see lactose. 
 
 the fat, lactin, and casein of, cleavage products from proteid 259 
 
 Mucin, " animal gum " the cleavage product of 35 
 
 cleavage experiments on 32 
 
 example of animal glucoside 27 
 
 Mucous membrane, intestinal, glucose-forming power of, even when dried . . 89 
 
 Muscle, sugar in 194 — 199 
 
 Myronic acid, example of sulphur-containing glucoside 27 
 
 Myxoedema, probable result of arrest of proteid-cleavage 259 
 
iKUEX. • 275 
 
 rAOE 
 
 Optical activity, diversity presented by the various sugars 52 
 
 negative behaviour of proteid-cleavage sugar 40 — 41 
 
 Osazones 17 
 
 Osazone crystals from sugar of egg, photo-engraviug of 207 
 
 — • of kidney, photo-eugraving of 201 
 
 ■ ■ of lung, photo-engraving of 203 
 
 of muscle, photo-engravings of 194 — -196 
 
 of normal urine, photo-engravings of ISS — 185 
 
 of spleen, photo-engraving of 200 
 
 from cleavage sugar, after passage of primary potash cleavage product 
 
 through a copper combination, photo-engraving of 42 
 
 • from pepsin digestion of egg albumin, photo-engraving 
 
 of 51 
 
 intermediate body, obtained in process of recovery of sugar from 
 
 cleavage-sugar osazone, photo-engraving of 47 
 
 proteid-cleavage sugar, photo-engraving of 38 
 
 after recovery from lead compound, photo-eugraving of 40 
 
 produced by direct action of sulphuric acid, photo- 
 
 engi-avings of 45 — 46 
 
 sugar in beef tea, photo-engraving of IIP 
 
 ■ of blood of general circulation, photo-engraviug of 158 
 
 of liver frozen instantly after death, photo-engraving of . . . . 138 
 
 of peptonised meat, photo-engraving of 120 
 
 of portal blood, photo-engraving of 107 
 
 . recovered from cleavage sugar osazone, photo-engraving of, . 48 
 
 Papain, example of peptonising ferment in plant 23 
 
 Pancreas, sugar in 202 
 
 Pancreatic extract, experiments with 85 — 87 
 
 juice, amylolytic power of 84 
 
 Pasteur, observations on proteid formation in yeast 239 
 
 on growth of yeast cell by incorporation of sugar 53 — 51 
 
 researches upon yeast 3, 20, 53 
 
 Pepsin digestion of albumin, sugar produced in 50 
 
 Peptone, interference with reaction of copper test 43 
 
 Peptonised meat, presence of sugar in 119 — 120 
 
 Peptone, probable conjugation of, with carbohydrate in villi 242 
 
 Phenyl-hydrazine, application to product of action of sulphuric acid on 
 
 albumin * 43 
 
 behaviour of proteid-cleavage sugar with 39 
 
 of sugars with 17 
 
 reaction given by sugar of normal urine 182 
 
 test, value of 48—49 
 
 value of, as a sugar test, in presence of peptone 119 
 
 Photo-engraving of glucosazone from sugar of liver taken in ordinary way 
 
 after death 140 
 
 • of osazone crystals from sugar of egg 207 
 
276 .INDEX. 
 
 PiOE 
 
 Photo-engraving of osazone crystals from sugar of sijleen 200 
 
 ■ from cleavage-sugar after passage of primary potash cleavage 
 
 product through a copper combination 42 
 
 • ■ — — from pepsin digestion of egg albumin 51 
 
 intermediate body obtained in process of recovery of 
 
 sugar from cleavage-sugar osazone 47 
 
 sugar in beef-tea 119 
 
 ■ ■ of blood of genei-al circulation 153 
 
 ■ of liver frozen instantly after death 138 
 
 of peptonised meat 120 
 
 of portal blood 107 
 
 • • recovered from cleavage sugar osazoiic 48 
 
 of proteid-cleavage sugar osazone 38 
 
 after recovery from lead compound 40 
 
 of sugar titrating apparatus ....-, 76 
 
 Photo-engravings of osazone crystals from normal urine 183 — 185 
 
 • muscle sugar 191 — 106 
 
 from proteid-cleavage sugar produced by dii'ect action of 
 
 sulphuric acid 45 — 46 
 
 Placenta and foetus, sugar in 204 
 
 Portal blood, amount of sugar in 101 — 108 
 
 form of sugar in, after ingestion of cane-sugar 98—99, 108 
 
 — — in relation to ingested carbohydrates 101 — 108 
 
 low cupric oxide reducing povper of sugar in 102 
 
 — nature of sugar iu 158 
 
 ■ jjroduct of starch digestion iu 89 — 90 
 
 sugar in, after fasting, after animal food, after starchy food, and 
 
 after sacchai'ine food 103 — 108 
 
 Potash, action on proteid 28 — 29 
 
 ■ employment of, in process of glycogen (amylose carbohydi'ate) extrac- 
 tion and estimation 63 
 
 injection of, into liver for preventing post-mortem production of sugar 134 
 
 Proteid, action of potash on 28—29 
 
 -cleavage by sulphuric acid 43^49 
 
 — — carbohydrate, more resistant than glycogen to action of sulph- 
 uric acid 65 
 
 . experiments, procedure adopted in 30 
 
 of, into fat, laclin, and casein of milk 259 
 
 origin of carbohydrate from 3 — 4 
 
 . product by potash, copper compound of 35 
 
 diff usibility of 35 
 
 ^_ preparation and properties of 33 — 35 
 
 .^ . resemblance to animal gum 35, 41 
 
 . . . strength of alcohol required for precipitation. ... 33 
 
 sugar, behaviour with phenyl-hydrazine 39 
 
 combination with lead oxide 39 
 
 effects of different strengths of sulphuric acid in obtaining. . 37 
 
 in relation to fermentation and optical activity 40 — 41 
 
 osazone, melting point of 48 
 
INDEX. 277 
 
 PAGE 
 
 Proteid-cleavage sugar, preparation and properties of 36 — 38 
 
 produced by ferment action 491 — 5 
 
 Proteid, eif ect of water at elevated temperature on 32 
 
 formation from carbohydrate by cells of villi 121 
 
 glucoside constitution of, bearings in relation to diabetes 229 
 
 matter, glucoside constitution of 27 — 57 
 
 of haricot bean, cleavage experiments on 31 
 
 production from carbohydrate 233, 239 — 24.5 
 
 sugar contributing to formation of 3 
 
 synthetic formation by incorporation of carbohydrate 53 — 55 
 
 of blood serum, cleavage experiments on 31 
 
 Proteids, various, cleavage experiments on 31 — 32 
 
 Proteolytic action, not province of liver but of digestive ferments 121 
 
 Protoplasm, action on carbohydrate 233 
 
 effects conversion of carbohydrate into fat 216 
 
 functions of 251 
 
 mode of effecting transformation of carbohydrate into fat 258 
 
 participation in deposition of starch 55—56 
 
 vegetable, constructive power of Ij 2 
 
 Protoplasmic action, " metabolic " and " plastic " power of 24 
 
 and ferment actions opposed in their effects 260 
 
 reciprocal play of 24 — 26 
 
 Ptyalin, amylolytic ferment of saliva 82 
 
 example of unorganised ferment (amylolytic) 19 
 
 Qualitative and quantitative sugar testing 68 — 80 
 
 Quantitative determination of sugar by ammoniated oiipric test 71 — 80 
 
 • gravimetrically 69 — 70 
 
 ■ of liver 136 
 
 RafEnose, constituti'>n of 45 
 
 Recovery of cleavage sugar from its osazone 46 — 48 
 
 Ruminant, exceptional position of stomach and intestine in relation to cane- 
 sugar inverting power 94, 96 
 
 Saccharoses, general description of 12 — 15 
 
 Saccharose, see cane-sugar. 
 
 Sachs, on participation of protoplasm in deposition of starch 55 — 56 
 
 on peptonising ferments in the vegetable kingdom 23 
 
 on production of ferments in plants 25 
 
 Salicin, example of non-nitrogenous glucoside 27 
 
 Saliva, amylolytic ferment action of 82 
 
 Schwann, on " metabolic " and '* plastic " power 24 
 
 Seeds, transmutations of carbohydrate in 25, 235 
 
 Seegen, on absence of difference between arterial and venous blood in relation 
 
 to sugar 171 
 
 on amount of sugar in blood 162 — 163 
 
 Sodium carbonate, effect on action of amylolytic ferments 84 — 87 
 
278 INDEX. 
 
 PAGE 
 
 Sodium carbonate diminishes ferment action in liver substance 155 — 156 
 
 sulphate, use in preparing products for analjsis 58 — 59, 62 
 
 ■ not to be used in preparing blood for cane-sugar estimation 108 
 
 restraining influence on inverting action of sulphuric acid 67 
 
 Spleen, sugar in • 200 
 
 Starch, action of alkalies, acids, and ferments ou 9 
 
 ■ action of saliva upon 82 
 
 ■ chemistry and properties of 8 — 9 
 
 conversion into sugar necessary for absorption 81 — 82 
 
 deposition in plant 3 — 4 
 
 digestion of 81 — '.10 
 
 digestion, product of, in portal blood 89 — 90 
 
 first visible primordial carbohydrate product 4 
 
 time required for conversion by sulphuric acid 66 — 67 
 
 Starchy food, portal blood after ingestion of 105 — 106 
 
 Stomach, absorption of sugar from 83 
 
 cane sugar inverting power of, large in rimiinant 94, 96 
 
 slight in animals generally 94—96 
 
 Stomach-contents, cane sugar inverting power of 97 — 98 
 
 Succus entericus, alleged lactose-transforming power of 99 
 
 glucose-forming capacity of 87 — 89 
 
 Sucrose, see cane sugar. 
 
 Sugar, amount and nature of, in portal blood after starch ingestion 89 — 90 
 
 ■ in blood considered generally 158 — 165 
 
 in blood of general circulation 161 
 
 iu general circulation not variable as in portal in relation to 
 
 food 112 
 
 in normal urine 186 — 187 
 
 ■ in portal blood 101—108 
 
 aqueous extraction of, from blood 159 
 
 blood in relation to 157 — 177 
 
 Briicke's process for separation of, from normal urine 179 — 180 
 
 cane, changes of glucose and cane sugar in the growing plant 21 — 22 
 
 ■ different glucoses in fresh and dead plant 41 
 
 change in nature and amount during incubation 208 — 210 
 
 contributing to formation of proteid ^ 3 
 
 determination of nature of 59 — 60 
 
 derived from tissues in severe diabetes 229 
 
 from ingested carbohydrates, liver in relation to 109 — 131 
 
 from proteid of animal food not produced in liver but by digestive action 121 
 
 in arterial and in venous blood 1 66 — 171 
 
 in brain 204 
 
 in egg 206—210 
 
 in generative organs of fish and Crustacea 205 
 
 in kidney 201 
 
 in liver at moment of death and afterwards, amount and nature of . 136 — 139 
 
 in liver of cold-blooded animal 140 — 143 
 
 — in lung 202—203 
 
 in muscle 194-199 
 
INDEX. 279 
 
 PAGE 
 
 Sugar in pancreas -^02 
 
 in placenta and foetus 204 
 
 in portal blood after fasting, after animal food, after starchy food, and 
 
 after saccharine food 103 — 108 
 
 in portal blood, low cupric oxide reducing power of 102 
 
 in spleen 200 
 
 kind of, in urine after injection of glucose 236 — 238 
 
 liver in relation to 132 156 
 
 methods of, extracting for analysis 58 — 62 
 
 nature of, in blood 1 57 — 158 
 
 in portal blood 158 
 
 of blood increased under abnormal conditions 163 
 
 ■ of liver, nature of 125 
 
 of normal urine, fermentability of 18V 
 
 • of tissues, process for ascertaining nature of. 132 
 
 of urine stands in relation to that of blood 187 — 193 
 
 possible existence of unknown modifications or varieties of 44 — 45 
 
 post-mortem production in liver 133 — 110 
 
 presence of, in beef tea 1 18 — 119 
 
 in healtliy urine 1 ' 8 — 186 
 
 present in animal food 118 — 1 19 
 
 production of, in alcohol-coagulated liver-substance 147 — 154 
 
 in liver after removal and washing free from blood 146—147 
 
 in liver during life under certain abnormal conditions 145 
 
 production from the tissues in diabetes 263 
 
 quantitative determination of, by the ammoniated cupric test 71 — 80 
 
 question of disappearance from blood after withdrawal 171 — 176 
 
 rapid production of in liver after death 125 — 126, 144 
 
 same amount in liver as in otlier structures during life 144 
 
 standard amount in blood of general circulation 101 
 
 starch converted by digestion into 82 
 
 stoppage of, by the liver, evidence of, afforded by the blood 109 — 112 
 
 by the organ itself 112 — 118 
 
 testing, qualitative and quantitative 68 — 80 
 
 urine in relation to 1 ' 8 — 193 
 
 Sugars, artificial, with 7, 8, and 9 carbon atoms 1 
 
 with less than 6 carbon atoms 1 
 
 Sulphuric acid, cleavage of proteid by 43 — 49 
 
 different strengths of, in relation to production of proteid- 
 
 cleavage sugar 3' 
 
 use of, in differentiation of carbohydrates 58 — 60, 62 
 
 Sun's rays, influence in production of organic compounds 1,2 
 
 Synthesis of carbohydrates 5 
 
 ' in plant 2 
 
 Synthetic formation of proteid by incorporation of carbohydrates 53 — 55 
 
 Temperature, moderately elevated, effect upon disappearance of sugar from 
 
 dr;iwn blood 1'4 — 175 
 
 Testing for sugar, qualitative and uantitative 68 — 80 
 
280 INDEX. 
 
 rAOE 
 
 Tortoise, liver rich in glycogen 131 
 
 Transmutation of carbohydrates 233 — 239 
 
 in seeds and tubers 25 — 26 
 
 of sugar into glycogen a process of dehydration 117 
 
 Tuber, transmutation of oarboliydrate in 26 
 
 Urine affords an index of the state, as regards sugar, of the blood 162 
 
 diabetic, glucose the form of sugar in, after ingestion of lactose 99 
 
 information derivable from, refutes glycogenic doctrine 225 — 227 
 
 in relation to sugar 178 — 193 
 
 kind of sugar present in, after ir jection of glucose 236 — 238 
 
 novm-il, amount of sugar in 186 — 187 
 
 behariour with Fehling's solution under different circumstances. . 178 
 
 presence of sugar in. 178 — 186 
 
 sugar of, stands in relation to that of blood 187 — 193 
 
 Taso-motor paralysis in connection witli diabetes 263 
 
 Vegetable kiugdom the source of carbohydrates 1 
 
 TUli, cells of, as fat-formers from carbohydrate 248 
 
 as proteid-formers from carbohydrate 242 — 244 
 
 possess power of forming proteid and fat from carbohydrate .... 121 
 
 photo-engraving of appearance of cells of, after fasting. . , . , . 253 
 
 of appearance of cells of, after ingestion of oats 253 
 
 of micro-photograpli representing appearance in section, after 
 
 fasting 254, 256 
 
 ■ after ingestion of oats 255, 257 
 
 Vitellin from yolk of egg. cleavage experiments on 31 
 
 Volumetric method of sugar determination 70 
 
 Water at elevated temperature, effect on proteid 32 
 
 Yeaat cell affords illustration of synthesis of proteid by incorporation of 
 
 carbohydrate 53 — 54 
 
 affords illustration of dehydration by living matter 20 — 21 
 
 cells, illustrating conversion of carboliydrate into fat 246 
 
 illustrating proteid formation from carbohydrate 239 
 
 occurrence of glycogen in 10 
 
 Zoamylin, a more appropriate term than glycogen 9 
 
 Zymogen 19 
 
 Zymolysis, see Fennent action. 
 
 nAEKI80K AND SONS, PRIKTERS IN ORDINARY TO HER MAJESTY, ST. MARTIN S LAKE. 
 
QP701 
 
 Pavy 
 
 P28 
 
 Copy