Cornell University Library The original of tliis book is in tlie Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003166653 \PRmENTED BY TSE AUTSOE. ADD E E S S RELATION OF FOOD TO WORK, ITS BEAEING ON MEDICAL PEACTICE ; DBLITBKED BEIOEE THE BRITISH MEDICAL ASSOCIATION, IN THE DIVINITT SCHOOL AT OXn&fi, ON THE EIFTH OE AUGUST, 1868, THE EET. SAMUEL HAUGHTON, F. E. S., M.D. DUEL., D. C.L. OXOK., rELLOW or TRINITY COLLEGE, DUBLIN. " IlidiciJum acri Fortius et melius magnas plenimque aecat res." )Jv5' buBLIlsfrX PRINTED AT '|r'iife/ir,])f:^T:EksiTY PRESS, BY M. H. GILE. 1868. ADDRESS OK THE RELATION OF FOOD TO WORK, AND ITS BEARING ON MEDICAL PKACTICE, &c. &c. Mb. President and Gentlemen, Man, like other animals, is born, grows, comes to maturity, reproduces his like, and dies ; passing in his lifetime through a cycle of changes that may be compared to a secular variation, by a metaphor borrowed from the science of Astronomy, while, in his daily life, he passes through a smaller cycle of changes that may be called periodic. From the time of the publication of Bichat's celebrated Essay on Life, and Death, it has been admitted that man and other animals possess a double life, animal and organic, presided over respectively by two distinct, though correlated centres of nervous force ; of these, one thinks, moves, and feels ; the other merely cooks ; receiving the food supplied, changing and elaborating it into elements suitable for the use of the animal life. In the lower forms of animals, the organic life becomes almost coextensive with the whole being of the creature,, a2 ( 4 ) which simply digests, assimilates, and excretes; but barely feels or moves. In the higher forms of animals, and more especially in man, the animal life dominates over the organic life, which becomes its slave, and exhibits the remarkable phenomena of mechanical force, of geometrical instinct, of ani- mal cunning, and finally, in man himself, produces intellectual work, rising to its highest form in the religious feeling that re- cognizes its great Creator, and bows in humility before Him. It is a simple matter of fact, and of every day observation, that all these forms of animal work are the result of the re- ception and assimilation of a few cubic feet of oxygen, a few ounces of water, of starch, of fat, and of flesh. The general question of the relation of Food to Work would involve a consideration of the possibility of throwing a bridge across the gulf that separates the organic from the animal life, so as to connect the products of nutrition (taken in its widest sense) with the work of every kind accom- plished by the animal life, whether mechanical or intellec- tual. We resemble the spiders of the heather on a summer morning, that float their gossamer threads into the air from the summit of a branch, in the hope that some stray breath of wind may fasten them to a neighbouring tuft, and enable the hungry speculator to extend the range of his rambles and his chance of food. Already a few feeble threads connect the chemistry of our food with the mechanical work done by our muscles ; when these shall have been securely fastened, from the higher vantage ground thus acquired, our little bridge of knowledgemaypossiblybe extended to embrace the phenomena of the geometrical instinct of the bee, or the cunning of the beaver : and our successors may even dare to speculate on the changes that converted a crust of bread, or a bottle of wine, in the brain of Swift, Moli^re, or Shakespeare, into the con- ception of the gentle Glumdalclitch, the rascally Sganarelle, or ( 5 ) the immortal Falstaff. At present such thoughts would be justly regarded as the dreams of a lunatic, and I must crave your indulgence for having mentioned them. The history of science is, however, filled with such dreams ; some never realized ; others converted by time into realities so common- place, that the genius of their originators is habitually for- gotten or underrated. During childhood and youth, the food that we eat is used for the double purpose of building up the tissues of the bones, muscles, brain, and other organs of the body ; and of supplying the force necessary for Work done, whether me- chanical or intellectual. In adult life, the first use of food almost disappears, for the bones, muscles, brain, and other organs, have already reached their full developement, and act simply as the media of communication between the Food received and the Work developed by it. Let us take, as illustrations, the muscles and brain, re- garded as the organs by means of which Mechanical and In- tellectual Work is done. These organs resemble the piston, beam, and fiy- wheel of the Steam Engine, and, like them, only transmit or store up the force communicated by the steam in one case, and by the products of the food conveyed by the blood in the other case. The mechanical work done by the steam engine must be measured by the loss of heat expe- rienced by the steam in passing from the boiler, through the cylinder, to the condenser ; and not by the loss of substance undergone by the several parts of the machinery on which it acts. In like manner, the mechanical or intellectual work done by the food we eat is to be measured, not by the change of substance of the muscles or brain employed as the agents of that work, but simply by the changes in the blood that supplies these organs — that is to say, undergone by the Food used, in its passage through the various tissues of the bodv. ( 6 ) befare it is finally discharged in the form of water, carbonic acid, or urea. The Divine Architect has so framed the animal machine, that moves and thinks, that the same blood, v^hich by its che- mical changes produces movement and thought, also repairs the necessary waste of the muscles and brain, by means of which movement and thought are possible ; just as if the steam that works an engine were able, without the aid of the engineer, to repair the wear and tear of its friction and waste spontaneously ; but no greater mistake is possible in Physio- logy, than to suppose that the products of the changes in the blood, by which Mechanical or Intellectual Work is done, are themselves merely the result' of the waste of the organs, whether muscles or brain, on the exercise of which that Work depends.* The ancients, who derived all their knowledge from ob- servation, and not from experiment, were well aware of the double duty imposed upon food in early life — of producing both the secular and the periodic variations of the body ; or, in .other words, of promoting growth, and of developing work. * The very bMII with ■which provision is made for the repair of the waste of the organ used as the instrument of Work may mislead the observer into suppos- ing that the -vrork itself may be measured by the waste of its instrument. Thus, it has been shown by Mr. A. Macalister, of Dublin, that the heart, which has im- posed upon it the necessity of working day and night without ceasing, during life, is furnished with double the usual supply of blood through the coronary ar- teries, which are injected twice for every single beat of the heart. If, indeed, it were possible to assume that all muscles wasted equally for equal quantities of work, and also to measure separately the jffoduots of that waste, we might then assume the waste of the organ as the measure of its work. Neither of these assumptions, however, can be admitted, for it can be shown that different mus- cles act under different conditions, more or less^advantageously, so that equal wastes would represent unequal works ; and also, it is impossible to separate in practice the products of waste of muscles from those of the general changes of the blood.. ( 7 ) Their practical knowledge is summed up by Hippocrates in the aphorism— " Old men bear want of food best ; next those that are adults ; youths bear it least, more especially children ; and, of these, the most lively are the least capable of enduring it."* The food consumed in twenty-four hours, including air and water, undergoes a series of changes of a chemical cha- racter before leaving the body, in the form of one or other of its excretions. Some of these changes develope force, and others expend force, but the algebraic sum of all the gains and losses of force represents the quantity available for work. This work must be expended as follows : — 1 . The Work of growth (secular). 2. The Work of maintaining Heat (periodic'). 3. Mechanical Work (periodic). 4. Vital Work (periodic). During childhood and youth the work of growth is posi- tive, for a certain proportion of the food used is employed in building up the tissues of the body instead of being expended in actual work ; it is, in fact, " stored up " in the body, as v.i» viva is stored up by the fly-wheel of machinery, and constitutes a reservoir of force that may be called upon at an emergency requiring sudden expenditure of force, as in case of illness ; or to supply the gradual wasting of old age. In adult life, and in old age, the work of growth ceases completely, except so far as is necessary to repair, from day to day, the small wastes of the organs employed in Work ; so that nearly the whole of the food employed is expended on the periodic work of the body. Hence we can readily see the reason for the aphorism, which asserts that food is more necessary for the young than * ripovTcg ivpopdiTara vtiariirjv ^ipovai, dcvrepov ol KadtariiKOTtQ ijKtaTa /xupaKta, jravriav Si /idXiirra waiSia, Tovriiov Si avTsuv & av Tv\y aiird 'iuVTZv npodviidrepa lovra. — Aph. I. 13.; ( 8 ) for the old, and more required by those of a lively disposition, either of mind or body, than by others. Hippocratic Doctrine of Innate Heat. Hippocrates was well aware of the connexion between food and animal heat, although he erroneously regarded the animal heat as an innate property of the body that caused an appe- tite for food, instead of being itself produced by food ; if we transpose his cause and effect, mutatis mutandis, all his maxims as to animal heat are true. Thus, he says — " Growing animals possess most innate heat, hence they require most food ; but the old have least heat, and therefore require the least fuel."* " The cavities of the body are naturally warmest in Winter and Spring ; .... in these seasons therefore most food must be given ; and since there is more innate heat, more nourish- ment is required ; as may be seen in youths and athletes. "f These maxims, when translated into modern language, ex- press the well-known fact, that the chemical changes of food that take place in the body produce animal heat, and that the necessity for food to supply mechanical work is greatest with the young and active, while the necessity for the production of animal heat is greatest in the cold seasons of the year. The direct connexion of food with mechanical work is ex- pressed in the following maxims : — " There should be no labour when there is hunger "| — * TA ai^avoiteva irXiXcrrov fj^" ri iji^vtov Bep/ibv, TrXeiarrig oiv deXrai Tpoptjc, yepovai Si 6\iyov rA dipjibv, Si& tovto dpa 6\i-yov virtKKav- ficLTwv dfovrai. — Aph. I. 14. t Al KoiXiai xHiiUvoQ xai rjpofi BipjioTarai (piaci Iv ravTyaiv oiv ryoiv utpyffi Kai rot irpotFapfxaTa irXgi'w Sorsov^ Kai yAp to ifjtfVTOv Qepudv nXdarov ixci, rpo^ijg oiv irXtiovog Jloirai. (rti/isiov al iiXtxiai Kai oi aeXrirai — Aph. I. 15. J "Okov XipJf, 01; Sil TTOvsiiv. — Aph. II. 16. ( 5 ) and its converse, " Let labour precede meals."* On principles such as those just given, the training of the athletes was conducted ; and they were compelled to undergo a regular course, commencing with blood-letting, and active purgation,t and consisting of systematic muscular exercise suited to the nature of the contest intended, accompanied by a dietary, of which the chief ingredients consisted of biscuits and pigs' kidneys, washed down by a minimum of water. It is, truly, not much to be wondered at, that those who sur-* vived the training were formidable in the boxing ring or racecourse. The relation of animal heat to respiration is referred to by Hippocrates, in a remarkable maxim. " Those persons have the loudest voices, who have most [innate] heat, for they inspire the largest quantities of the cold air; and the product of two great quantities must be itself great."J Galen believed the heart to be the centre of "innate heat," but he was well aware that increase or diminution of respira- tion caused increase or diminution of heat, and was intimately connected with it. Thus he says : " Since, therefore, the heart is, as it were, the hearth and fountain of the innate heat, with which the animal is per- vaded," &c.§ " The necessity for respiration is the greatest and most im- perious guard of the innate heat."l| * Hovoi aiTitav fiyctaOwirav. — Epid. VI. Sect. iv. 28. t "EXeea iic^vovaiv fiv aicaSaproe Iwv vovijiTy. — Epid. VI. Sect. v. 32. J OliTi nXelaTov r4 Bep/ibv, jMEyaXo^wj'draToi, xai y&p i^uxP^f ^^P vXtla- ToQ, dvo Sk fxeyaXiiiV fisyaXa Kai tcl ^Kyova yivtrai. — Epid. VI- Sect. iv. 32. § fiTret Toivvv rj KapSia TrJQ sfitpvTov BipfiaalaQj y StoiKsirai rd ZSiov^ olov idTia 7-8 TiQ ian xai vny/i k t, X.^De iisu partium, Lib. yi. ch. 7. II rf XPE'« ^VQ avairvoiJQ ri fieyiiTTrj fikv Kai KvpiftiTarrj fvXaKt] r^ff iliipvTov Ofpitaaiag ivriv. — De diff. Reap. Lib. i. ch. 4. ( 10 > " Those persons in whom the innate heat has been much cooled, breathe but little and slowly."* Lavoisier s Theory of Animal Heat. The doctrine of " innate " heat, taught by Hippocrates and Galen, ruled in Medicine for 1500 years after Galen's death ; until it received its death blow from the genius of Lavoisier, who demonstrated in his celebrated memoir read before the French Academy of Sciences in 1783, that the source of "Animal heat is to be found in the combustion of the carbon of the body by the oxygen of the air received into the lungs by respiration. Lavoisier's experiments were repeated and confirmed in 1 822 by Dulong and Despretz ; and have formed the starting point for all modern investigations on the relation of food to work. As already stated, the work done by food in the body may be divided into 1. The Work of Growth. 2. The Work of Animal Heat. 3. Mechanical Work. 4. Vital Work. Lavoisier arranged his experiments so as to exclude almost all the foregoing kinds ofwork, except that of animal heat. A Guinea-pig was placed under a bell glass inverted over a surface of mercury, and a current of fresh air was allowed to circulate through the apparatus, being passed at its final exit through tubes containing caustic potash, which arrested the carbonic acid produced by the animal. In this manner it was easy to ascertain the carbonic acid excreted, by the in- crease in weight of the tubes of caustic potash during the experiment. Lavoisier found that his Guinea-pig, in ten hours, burned, * iiairip Kfli orav lUK^bv kiairveiiiai Kai PpaSeus,-olsiKaviis I^vktui ri ifijivTov 6(pii6v. — De diff. Eesp. Lib. i. oh. 20. ( 11 ) on the average, 3-333 g™is. of carbon; and this quantity of carbon he estimated from other experiments as capable of melting 326.75 grms. of ice at the freezing temperature. The same Guinea-pig was then placed in an ice calorimeter, and left in it for ten hours, during which time the heat of its body- was found to have melted 402-27 grms. of ice at the freezing temperature. If we use, instead of the coefficient of combustion of car- bon employed by Lavoisier, that now generally adopted from the experiments of Favre and Silbermann, the quantity of melted ice represented by 33 grms. of carbon would become 364.78 grms., instead of 326.75 grms. We are, therefore, en- titled to say that the heat of combustion of expired carbon determined by Lavoisier is equal to 36478 .„ - — — = 00.68 per cent. 402.27 of the animal heat developed, which is regarded as 100 parts. Two years later, in 1785, Lavoisier laid before the Koyal Society of Medicine of Paris, an account of further experi- ments, also conducted on the breathing of Guinea-pigs, by which he showed, that of 100 parts of oxygen absorbed by those animals, 8 1 only reappeared in the form of carbonic acid, and 19 parts disappeared altogether. Lavoisier consi- dered that these 19 parts of oxygen were employed in the body in the combustion of hydrogen, the product of such combustion being water. If we use Lavoisier's datajust givenj and the known atomic weights of carbon, oxygen, and hydrogen, we shall have, for 81 parts of oxygen in the form of carbonic acid, and 19 parts- of oxygen in the form of water, the following quantities of carbon and hydrogen consumed by the respiration of his- Guinea-pig in the same time : — ,,, , <5 X 81 TT J 19 Carbon = ;— Hydrogen = -~ 16 ■' ° & ( 12 ) Multiplying these numbers by the Heat Coefficients of Favre and Silbermann, we find — Heat' produced by Carbon = — - — x 8080 Heat produced by Hydrogen = -^ x 34462 8 It has been already shown that the heat developed by the- combustion of carbon in Lavoisier's experiment amounted to 90.68 per cent, of the heat emitted by the animal; hence the heat produced by the combustion of the hydrogen will amount to ^„ 19 X 34462 16 90.68 X -^ — I X 2 — 5 a-^ = 30.24 8 6 X 81 X 8080 ^ By adding together the heats due to the carbon and hydrogen, we find that Lavoisier's experiments, when fairly interpreted by the data of modern science, give the following results : — Heat produced by the combustion of carbon and hydrogen, 120.92 Animal Heat 100.00 Finally, in 1789, Lavoisier published further experiments, by which he showed conclusively that the consumption of oxygen by the body is notably increased by three causes — 1°. By a lowering of the external temperature. 2°. By the act of digestion. 3°. By muscular exercise. The experiments of Lavoisier were repeated in 1822 by Dulong and Despretz, and their results, when corrected, like those of Lavoisier, by using the modern heat coefficients of carbon and hydrogen, are as follows : — The mean ofDulong's experiments on 16 animals and birds is 90.6 per cent, of the animal heat given out — the ( 13 ) lowest number, 85.5, belonging to a kitten 60 days old ; and the highest number, 99.4, belonging to a puppy co days old. M. Degpretz obtained an average of 92.3, from 16 mam- mals and birds; his highest number being 10 1.8, derived from an old female rabbit; and his lowest number being 84.2, de- rived from 4 owls. The foregoing experiments left no doubt remaining in the minds of men of science as to the substantial truth of Lavoi- sier's doctrine of animal heat ; and led immediately to a num- ber of supplementary experiments, amongst the most remark- able of which were those of Regnault and Keiset. Regnault directed his attention especially to the distribu- tion of the oxygen absorbed by animals, between the carbon and hydrogen of their blood, or tissues, which had been laid down by Lavoisier in the proportion of 8i to 19, He found that the proportion was not a fixed one, but varied with the food in a very instructive manner. The average of his experiments on 14 animals, including worms, lizards, and insects, as well as birds and mammals, was — Oxygen combined with carbon, . . 81.7 Oxygen combined with hydrogen, . 19.3 a result nearly identical with that found by Lavoisier. The highest proportion of oxygen combined with hydrogen, oc- curred in the case of chickens fed on meat, and amounted to 32 per cent. ; and the lowest proportion occurred in the case of rabbits fed on bread and oats, and amounted to I per cent. only. Still more recent experiments, made with improved ap- paratus and methods by Pettenkofer and Voit, in Munich, show, like those of Eegnault, that the proportion of the oxy- gen employed in forming carbonic acid, to the whole oxygen absorbed, varies with the food, ranging in the case of a large ( 14 ) dog from 52.4 to 148.2, according as the animal was kept altogether without food, or fed upon a mixed diet of meat and sugar. These investigations have also shown that, under ordinary conditions, it is probable that a dog consumes nearly all the oxygen absorbed in the formation of carbonic acid. Before leaving the subject of animal heat, it is worth while to estimate its amount in a manner that wiU bring it into com- parison with ordinary mechanical work. In Lavoisier's experiment with the Guinea-pig, 402.27 grms. of ice were melted in ten hours ; ftom this fact we find, assuming the latent heat of ice at 142° F., and 772 as Joule's coefficient for converting British heat units into foot pounds. Mechanical work equivalent to the daily animal heat of La- voisier's Chdnea-pig = 402.27 X 24 X 142 X 15-432 X 772 7000 X 10 = 233310 ft. lbs. As the average weight of a Guinea-pig is 4 lbs., the pre- ceding amount of work, representing animal heat, would be sufficient to raise the weight of the animal through a ver- tical height of 23331° 4 X 5280 = 1 1.05 miles. Kanke has shown, by experiments made upon himself, under various conditions of food and fasting, by means of Pettenkofer and Voit's apparatus, that his daily excretion of carbonic acid varied from 660 grms. to 860 grms., showing a mean of 760 grms. His weight was 67 kilos.,jfrom which fact, and the assumption that an English mile is 1600 meters, we obtain, employing the constants already given, the height ( 15 ) through which the combustion of 760 grms. of carbonic acid ■would raise the weight of 67 kilos, in 24 hours — 760 X 6 X 8.080 X 42q , , ., = :p 7 = 0.600 miles. 22 X 67 X 1000 ^ The extreme values of the carbonic acid excreted, viz. 660 grms. and 860 grms. would correspond to the heights of 5.74 miles, and 7.48 miles respectively. Dr. Edward Smith has estimated the daily excretion of carbon from the lungs, in the case of four persons, as fol- lows : — Body Weight. Carbon. Mr. Moul, . . . 173 lbs. . . . 6.735 °^' Dr. E. Smith, . . 196 ,, ... 7.85 „ Prof Frankland, . 136 „ ... 5.60 „ Dr. Murie, ... 133 „ ... 6.54 „ In order to convert the preceding data into vertical miles through which the body weight is lifted, we must multiply the ounces of carbon by the following coefficient, and divide the product by the body weight. _, „ 8080 X 9 X 772 10 X 5 X 5280 ^ ^ log. (coeff.) = 2.1235473 We thus obtain, for the heights through which the carbon consumed would lift the observers — Mr. Moul 5.17 miles. Dr. E. Smith, .... 5.32 „ Prof. Frankland, . . . 5.47 „ Dr. Murie, 6.53 „ Pettenkofer and Voit succeeded in producing a range of carbonic acid excreted by a large dog, weighing 33.3 kilos., from 289.4 grms. to 840.4 grms; the minimum corresponding ( 16 ) to the loth day of fasting from solid food, and the maximum corresponding to a diet of 1800 grms. of meat, 350 grins, of fat, and 1410 grms. of water. It may be easily shown by a calculation similar to the foregoing, that these excretions of carbonic acid correspond to the mechanical works of lifting the weight of the dog through vertical heights of 5.03 miles, and 14.62 miles respectively. Combining together the preceding results, and expressing them all in the natural units of the weights of the animals lifted through a height, we find — Work due to Animal Heat. Man. I. 2. 3- 4- 5- 6 Dr. Eanke (fasting), . . Dr. Eanke (well fed), . . Mr. Moul, Dr. E. Smith, .... Prof. Frankland, .... Dr. Murie, . 5.74 miles • 7-48 „ • 5-17 >. • S-32 „ • 5-47 .. 6. CI Mean, . . . 5.952 miles This result agrees very closely with the - calculation al- ready made from 760 grms. of carbonic acid, in the case of Dr. Eanke ; viz. 6.609 niiles. Work due to Animal Heat. Animals. 1. Guinea-pig, 11.05 miles. 2. r^og (fasting), 5.03 „ 3. Dog (overfed), 14.62 ,, Mean, .... 10.233 miles. ( 17 ) Source of Muscular Work. As soon as it was satisfactorily established by Lavoisier and his successors that the natural combustion of carbon and hydrogen in the blood was sufficient, or somewhat more than sufficient, to account for the animal heat, it became a |matter of great interest to physiologists to ascertain, if possible, how much of the work developed in the blood by chemical changes is employed in producing animal heat, how much in mechanical work, external and internal, and how much in vital or mental operations. At the outset of this inquiry, it received a misdirection from the conjecture thrown out by Liebig, that the excretion of nitrogen (in the form of urea) gave necessarily the measure of the wear and tear of the muscular tissues themselves, which are composed of proteinic or nitrogenous compounds. This conjecture led to Liebig's celebrated classification of food into Heat-producing and Flesh-forming foods, which has been unhesitatingly received until lately, in this country, by physio- logists and physicians. Before investigating the truth or false- hood of Liebig's theory, it is worth while to state the most recent results obtained as to the muscular work per day of which man is capable. From numerous observations, of which some were made by myself on the daily labour of hodmen, paviours, navvies, and pedlars, I have obtained the following mean : — Daily labour of Man = 353.75 ft. tons. = 109549 kil. met. This quantity of work is the exact equivalent of the work done by a man of 150 lbs. weight in climbing through one mile of vertical height, and is, as I have already shown, about one-sixth part of the work expended in producing and main- taining animal heat. I was led to believe, from investigations made to determine B ( 18 ) the quantity of urea excreted in various diseases, that a certain minimum quantity, equivalent to 2 grs. per pound of body weight, -was excreted quite independently of muscular exertion, and I proved that death was preceded in many chronic dis- eases by a fall in the urea excreted to 2 grs. per pound. These investigations were made chiefly on patients dying of advanced kidney disease, in which the excretion of albumen had nearly or altogether ceased, and on patients dying of phthisis. Pettenkofer and Voit found that the excretion of urea in a dog reduced from 33.3 kilos, to 29 kilos, by 10 days' fast be- came 8.6 grms. And, since 29 kilos = 63.8 lbs. 8.6 grms. = 132.7 grs. Excretion of urea = 2.08 grs. per lb. of body weight. Eanke obtained a precisely similar result from observations made upon himself, after long fasting, continued for several days. If these views be well founded, it is plain that part only of the urea excreted can be regarded as due to muscular exer- tion, for 2 grs. per lb. (or 300 grs. for a man weighing 1 50 lbs.) must be set aside as a constant due to vital work, independent of muscular work altogether. Hence it would follow, sup- posing the muscular exertion to be measured by the increased excretion of urea produced by. it, that the urea will not in- crease as fast as the muscular exertion, but it ought to increase regularly, although at a slower rate. With a view to settle this important question, I devised the following observations upon myself in the month of July, 1866, which prove conclu- sively that an increase of muscular exertion, amounting to fourfold, is not accompanied by any corresponding increase in the excretion of nitrogen, in the form of urea. I had previously ascertained by repeated experiments, ex- ( 19 ) tending from i85o to 1865, that my excretion of urea (under ordinary conditions as to exercise, which never amounted to five miles per day), ranged from 465.09 grs. per day, to 537-47 grs- per day. S01.28 mean. This quantity of urea I regarded as my natural physiolo- gical average, and it was so well established, that I thought I should obtain an important result by comparing it with the average found from several days of unusual muscular exer- tion. I accordingly walked for five consecutive days in the hilly districts of Wicklow, noting carefuUy the horizontal dis- tance travelled each day, and the vertical height traversed up and down. The vertical heights were reduced to horizontal distances, on the assumptions (which are well founded) that 20 is the proper coeflB.cient for converting one into the other, and that the work of descent is half the work of ascent. During the five days of observation the work done, ex- pressed in horizontal miles of walking, was as follows: — First Day. Miles. Miles walked, 11.4 Height ascended, .... 1800 ft. = 10.2 21.6 Second Day. Miles walked, 12.0 Height ascended, .... 2400 ft. = 13.7 25.7 b2 ( 20 ) Third Day. Miles walked, 1 1 -6 Height ascended, .... 1400 ft. = 8.0 19.6 Fourth Day. Miles walked, 9-3 Height ascended 1400 ft. = 8.0 17-3 Fifth Day. Miles walked, 10.4 ■Height ascended, .... 1600 ft. = 9.1 19.5 From the preceding statement it follows that the average ■work done each day was 20.74 miles of horizontal walking — the result of which upon the urea excreted was to be com- ,pared with the result already mentioned, as a physiological ■constant determined under circumstances in which the daily muscular work never exceeded 5 miles of horizontal walking. In order to determine the urea, I collected each day all the urine passed, and kept one-fifth part of it ; and at the close of the fifth day examined the mixture formed from the five days' urine. It was found to contain 501.16 grs. of urea per day — a result practically identical with the physiological quantity previously found by me under totally diflFerent con- ditions, viz. J01.28 grs. I was much surprised at this result, for I had previously believed in the theory laid down by Liebig, which attributed the excretion of urea to the disintegration of muscular tissue. ( 21 ) It might be objected to the preceding reasoning, that the combustion of proteinic compounds represented by 501.28 grs, of urea excreted is actually sufficient to produce the mecha- nical force necessary to maintain the muscular exertion of walking 20 or 21 miles per day. 1°. The urea excreted bears to the proteine consumed the proportion of 24 to 79 ; as appears from their chemical com- positions — viz., Urea, . . C, H^ N, 0, . . 60 Proteine, . Cae Hg, N4 O^ . . 395 2°. In 100 parts of proteine there are 53.7 parts of carbon,. and 7 parts of hydrogen ; the total heat due to the combustions of I grm. of proteine is, therefore, Heat Units. 0.537 grm. of Carbon, .... 4.3389 0.070 grm. of Hydrogen, .. . . 2.4123 6.7512 This number, 6.7512) represents the maximum quantity of heat units* that could be produced by the combustion of i. grm. of proteine ; but the term depending on hydrogen in it should be reduced to |ths of its amount, in consequence of the hydrogen already combined with oxygen in the proteine. Hence we find — Combustion of i grm. of Proteine. Carbon, , . . .4.3389 heat units.. Hydrogen, .... 1.3402 „ 5.6791 3". In 100 parts of urea there are 20 parts of carbon, and 6^ * Heat unit = i kilog. of water raised i" C. ( 22 ) parts of hydrogen ; the total heat, therefore, due to the com- bustion of I grm. of urea is 0.20 grm. Carbon, . . . . . 1.6160 0.067 g^"^' Hydrogen, .... 2.3089 3.9249 The term depending on hydrogen, in this result, should be reduced to ^, in consequence of the hydrogen already combined with oxygen in the urea. Hence we find — Combustion of i grm. of Urea. Carbon, . 1.6160 Hydrogen, 11544 2.7704 4°. From the three preceding statements it is easy to see that, for every gramme of proteine consumed, 0.8416 heat units are contained in the urea excreted ; so that The Digestion of 1 grm. of proteine gives out 4.8375 heat- units. It is easy to see that 501.28 grs. of urea excreted corre- spond to 1650 grs. of proteine in the food, or to 106.92 grms. ;. and the total work due to the digestion of this quantity of food may be found by multiplying it by the " Digestion coefficient" already found, and by 423, which is Joule's coefiB.- cient for converting heat-units into kilogr ammeters. Hence we have — Work due to production of 501.28 grs. of urea = 106.92 X 4-8375 X 423 = 218786 k. m. = 704 ft., tons. ( 23 ) This amount of theoretical work produced by nitrogenous food is double the work actually done during the walking excursion. The average work was 20.74 miles horizontal per day, which may be considered as the exact equivalent of lift- ing my weight (knapsack and clothes included = 150 lbs.) through one mile of vertical height. Hence the work actualljr done by me was 150 X 5280 , — = ^?4 ft. tons. 2240 •'^^ This amount of muscular work accounted for almost exactly half the whole theoretical work supplied by the food that goes to form urea, viz. 704 ft. tons. ; but it has been already shown that 2 grs. of urea per pound of body weight is- required to maintain the vital work, including circulation and respiration; this would give (since I weighed 128 lbs.) 256 grs. of urea, required fy Dr. Mayer of Heilbronn, and recently developed with much ability, by Mr. C. W. Heaton, of Charing Cross Hospital, in the Philosophi- cal Magazine for May, 1867, that the blood itself is the seat of all the chemical changes that develope force in the body, has gained favour among physiological chemists, and also met with acceptance among practical clinical observers. Thus the human mind revolves in cycles, and the physicians of the nineteenth century are preparing to sit at the feet of Moses, and learn that the blood of an animal really constitutes its life ; while South African theologians are disposed to re- ( 26 ) ject his authority, because he happened to confound a Rodent with a Ruminant.* Whatever be the kind of food employed, its effect in the production of force must be ultimately measured by the quan- tities of carbonic acid and water produced by its combustion, and there is no more convenient measure of the production both of carbonic acid and water than urea, so far as it goes. I shall prove shortly that every four grains 'of urea excreted represent five tons lifted through one foot ; and I have shown by the preceding investigation that the work represented by urea is not sufficient to account for vital and external work, much less for animal heat. The investigations of Dr. Edward Smith, on the excretion of carbonic acid, enable us to show that the carbonic acid alone is sufficient to account for both vital and external work, and also for the production of animal heat. This may be proved as follows : — Dr. Smith has given results, from which may be deduced the quantities of carbonic acid excreted per minute, during the four following conditions : — 1. Lying in the horizontal position, and nearly asleep. 2. Fasting, and in sitting posture. 3. Walking at two miles per hour. 4. Walking at three miles per hour. 5. Working on the Treadmill, ascending at the rate of 28.65 feet per minute. Carbonic acid per min. 1. Sleep and rest, 5.522 grs. 2. Sitting, 3. Walking at two miles per hour, 4. Walking at three miles per hour, 5. Treadmill, 7.440 18.100 25.830 44-973 * No reasonable person can fail to perceive the ignorance of the great Law- giver, who will apply to him the test first proposed by Swift for Homer; Moses, like the author of the Iliad, was profoundly unacquainted with the disci- pline and doctrines of the Church of England. ( 27 ) The foregoing quantities of carbonic acid per minute may- be converted into vertical miles per hour for the body weight, by multiplying them by the following coefficient :* — 60 X 6 X 8080 X g X 772 ■ 2 5 — — = 0.025263 22 X 196 X 5280 X 5 X 7000 ■' •' log. = 2.40420 Performing this calculation we find — Carbonic Acid. ^''^o^S?^' 1. S-522 grs. 0.1400 mile. 2. 7.440 „ 0.1887 '> 3. 18.100 „ 0.4591 „ 4- 25.830 „ 0.6551 „ 5- 44-973 » 1.1406 „ It is easy to calculate that the external work done in the cases 3, 4, 5, was as follows : — External Work. No. 3. Walking two miles per hour, . o.iooo mile. No. 4. Walking three miles per hour, . 0.1500 „ No. 5. Treadmill, 0.3256 „ Subtracting these amounts of work from the applied work, due to the production of carbonic acid, we find, as the quan- tities left for Vital Work, including circulation and respira- tion, and for the production of Animal Heat, per hour : Vital Work and Animal Heat. No. 3. 0.3591 mile. No. 4. 0.5051 „ No. 5. 0.8150 „ As I have already shown the work due to animal heat per day to be 6 miles ; it follows that the work of animal heat per hour is 0,2500 mile. * Dr, Edward Smith's weight was 196 Iba. ( 28 ) Deducting this amount from the foregoing, we find for the Vital Work done, under the three different conditions — Vital "Work._ No. 3. Walking at two miles per hour, 0.1091 mile. No. 4. Walking at three miles per hour, 0.2551 „ No. 5. Treadmill work 0.5650 ,, This result proves, in a striking manner, the great disad- vantage under which an increased amount of muscular work is done, in a given time ; and it is quite in accordance with other results obtained by me from totally different experi- ments. No two classes of animals can well differ more from each- other than the Cats and Ruminants, one of which is intended by nature to eat the other. They differ in all respects as to food, the Cats requiring a supply of fresh meat and blood for theii health, and the Ruminants being exclusively vegetable feeders ; yet in both classes we find a great developement of muscular power, and of rapid action of muscles, qualities alike necessary to the pursuer and to the pursued. There can be no doubt that muscular work is developed in the Cats from the com- bustion of flesh, and in the Ruminants, mainly, if not exclu- sively, from farinaceous food. It is, however, worthy of remark, that the muscular qualities developed by the two kinds of food, differ considerably from each other. The hunted deer will outrun the leopard in a fair and open chase, because the work supplied to its muscles by the vegetable food is capable of being given out continuously for a long period of time ; but in a sudden rush at a near distance, the leopard will infallibly overtake the deer, because its flesh food stores up in the blood a reserve of force capable of being given out instantaneously in the form of exceedingly rapid muscular action. In conformity with this principle, we find among ourselves an instinctive preference given to farinaceous and fatty foods, or to nitrogenous foods, according as our occupations require- ( 29 ) a steady, long-continued, slow labour, or the exercise of sud- den bursts of muscular labour continued for short periods. Thus Chamois hunters setting out for several days' chase pro- vide themselves with bacon fat and sugar ; the Lancashire la- bourers use flour and fat, in the form of apple dumplings ; while the Red Indian of North America almost transforms himself into a carnivore, by the exclusive use of flesh food; he sleeps as long, and can fast as long as the Puma or Jaguar, and possesses stored up in his blood a reserve of force which enables him, like a cat, to hold his muscles for hours in a rigid posture, or to spring upon his prey, like a leopard leaping from a tree upon the back of an antelope. If the preceding view of the muscular qualities developed by the two kinds of food be correct, important inferences sug- gest themselves as to the food that should be employed in relation to several kinds of work. Of these inferences, I shall select two examples : — 1. The nurses of one of our Dublin Hospitals were for- merly fed chiefly upon flesh food and beer, a diet that seemed well suited to their work in ordinary times, which was occa- sionally severe, but relieved by frequent intervals of complete rest. Upon the occasion of an epidemic of cholera, when the hospital duties of the nurses became more constant, although on the whole not more laborious, they voluntarily asked for bacon fat and milk, as a change of diet from the flesh meat and beer ; this change was effected on two days in each week with the best results as to the health of the nurses, and as to their power of discharging the new kind of labour imposed upon them, 2. I have been informed, on competent authority, that the health of the Cornish miners breaks down ultimately, from failure of the action of the heart and its consequences, and not from the affection of the lungs called "miner's phthisis." The labour of the miner is peculiar, and his food appears to me ( 30 ) badly suited to meet its requirements. At the close of a hard day's toil, the weary miner has to climb by vertical ladders through a height of loo to 200 fathoms before he can reach his cottage, where he naturally looks for his food and sleep. This climbing of the ladders is performed hastily, almost as a gymnastic feat, and throws a heavy strain (amounting from one-eighth to one-quarter of the whole day's work) upon the muscles of the tired miner, during the half hour or hour that concludes his daily toil. A flesh-fed man (as a Bed Indian) would run up the ladders like a cat, using the stores of force already in reserve in his blood ; but the Cornish miner, who is fed chiefly upon dough and fat, finds himself greatly distressed by the climbing of the ladders — more so indeed than by the slower labour of quarrying in the mine. His heart, over- stimulated by the rapid exertion of muscular work, beats more and more quickly in its efforts to oxidate the blood in the lungs, and so supply the force required. Local congestion of the lung itself frequently follows, and lays the foundation for the affection, so graphically, though sadly, described by the miner at 40 years of age, who tells you that " his other works are very good, but that he is beginning to leak in the valves." Were I a Cornish miner, and able to afford the luxury, I should train myself for the " ladder feat " by dining on half a pound of rare beefsteak and a glass of ale, from one to two hours before commencing the ascent. The excretion of nitrogen by the Cats and Ruminants is very different, as might be expected from their food. I have ascertained that the urea discharged by a Bengal Tiger and a Sheep, daily, is as follows : — Bengal Tiger, .... 4375 grs. of urea. Sheep, 256 ,, It is worthy of remark, and serves to throw light on the meaning of the excretion of nitrogen from the body, that ( 31 ) causes but slightly connected with muscular exertion in the Euminants increase amazingly the excretion of urea. Thus I have found the following excretion of urea from a Earn during the rutting season : Eam (rutting season), . . . 1493 grs. of urea. This amounts to a sixfold increase of urea, which cannot possibly be accounted for by the food consumed at the time, but requires us to assume a certain storing up of force, repre- sented by nitrogenous compounds, which has been going on for a considerable period previous to the rutting season. A similar and equally remarkable storing up of phosphates and carbonates takes place, previous to the rutting season, in the Euminants that shed their horns, which in the Cermis Megace- ros often weigh 90 lbs. These remarkable phenomena remind us of the maxim of the wise. Hippocrates, who recommends moderation in the use of the gifts of the Golden Venus, as well as in those of Ceres and Bacchus — TTovoi, airla, irora, virvog, cKppoSiata fitrpia, with which may be compared its converse in the Latin pro- verb — Sine Cerere et Baccho, friget Venus : or, as the old proverb says ; When the wolf comes in at the door, love flies out at the window. Application of Theory to Diseased Conditions of Body. The relation of food to work, complicated enough in health, becomes more so in disease, and the problem to be solved by rational theory becomes still more difficult. I can- not attempt even to sketch an outline of this part of my subject ( 32 ) considered in general, but shall content myself with asking your attention to three remarkable examples of disease which illustrate the principles I have attempted to lay down. These diseases are — A. Typhus Fever. ~B. Cholera Asiatica. C. Diabetes mellitus. A. Typhus Fever. — In Typhus fever a prominent symptom is the remarkable elevation of temperature, accompanied by an increased excretion of urea and carbonic acid, by the kid- neys and lungs, indicating (as no food is taken) an increased morbid metamorphosis of the blood and tissues. The tem- perature commonly rises to 104° F., representing an increase of upwards of 5° F. above the normal temperature. If we knew the cause of this increase of temperature, or rather of the increased metamorphosis of which it is the sign, we should know the cause of Typhus fever, and learn to com- bat the disease on rational grounds. At present the cause is unknown, and therefore the physician is forced to treat the symptoms as they appear, instead of attacking the cause of the disease. Let us examine for a moment the terrible sig- nificance of the symptoms. Your patient lies for nine or ten days, supine, fasting, subdelirious ; the picture of weakness and helplessness ; and yet this unhappy sufferer actually performs, day by day, an amount of work that might well be envied by the strongest labourer in our land. The natural temperature of the interior of the body is 100° F., while the temperature of the corresponding parts in Typhus fever is at least 105° F. This seems at first sight a small increase — only 5 per cent, of the whole ; but it is in reality 2J times as great as it appears, and actually amounts to 125 p. c, or one-eighth part of the total animal heat. For ( 33 ) the total quantity of heat given out by the heated body is proportional (from Newton's law of cooling) to the elevation of its temperature above the temperature of equilibrium, to- wards which it tends. If we suppose this equilibrium tem- perature to be 60° F., then the quantities of animal heat given out in Typhus fever and in health will be in proportion of 45 to 40, showing that the animal heat of Typhus exceeds that of health by one-eighth of its amount. We have already seen that the work due to Animal Heat would hft the body through a vertical height of 6 miles per day ; and it thus appears that an additional amount of work, equivalent to the body lifted through nearly one mile per day, is spent in maintaining its temperature at Fever Heat. If you could place your fever patient at the bottom of a mine, twice the depth of the deepest mine in the Duchy of Cornwall, and compel the wretched sufferer to climb its ladders into open air, you would subject him to less torture, from muscular exertion, than that which he undergoes at the hand of nature, as he lies before you, helpless, tossing, and delirious, on his fever couch. The treatment of this formidable disease in former times consisted of purging, vomiting, and bleeding the patient, with the view of eliminating an imaginary poison, and so helping nature to terminate the disease.* In modern times, thank God, the physician either does not interfere at all; or adopts the rational process of retarding the disintegration of the tissues consumed to supply the fever heat, by furnishing in their stead, fuel, in the form of wine and beef tea, sufficient to maintain the increase of temperature imperiously required. t This practice may be justly considered * Novffuv ^iattQ itjTpoi. — Epid. vi. Sect. v. i. t It is not intended by this to assert that a high temperature, 104° to io8°F., must be maintained, in order that the disease may terminate favourably, forjthe very contrary is the fact. The blood, in Typhus, as in other pyrexies, is a fluid C ( 34 ) rational, because the condition of the circulation admits of its application, and it is considered good, because it has been rewarded with success, in the hands of the skilful clinical physician. In concluding this sketch of the prominent symp- tom of Typhus fever, and as an illustration of the eagerness with which every possible combustible in the body is made use of, I may mention, on the high authority of Dr. Stokes, of Dublin, that the very urea excreted by the kidneys is not per- mitted to leave the body without first paying its tax to fever, by being burned into carbonate of ammonia, thus rendering the urine of an advanced case of bad Typhus fever eminently alkaline. B. Asiatic Cholera. — This remarkable disease presents, as every one knows, three distinct stages, viz., possessed of greater oxidising power than it has in health ; in consequence of this, an increased metamorphose of tissues takes place, accompanied of course by an elevation of temperature, which measures precisely the oxidising power of the blood, and the risk to life in Typhus is directly proportional to the rise in temperature. The indications of the sphygmograph are similar to those of the thermometer, a "full dicrotii/' pulse corresponding to a temperature of 103° F., and the pulse of " death agony," with the heart's first sound gone, corresponding to a temperature of 109° F. There is no case on record of recovery from a con- dition marked by such a pulse and temperature. The effects of alcohol, administered in fever, when the temperature does not exceed 105° F., are twofold — immediate and secondary. The immediate effect is to supply a hydrocarbon to the blood, which is decomposed by it in prefe- rence to the body tissues. The secondary effect of alcohol is to change the blood itseU) which thus loses its oxidising qualities ; in consequence of which the temperature falls, the hyperdicrotic character of the pulse disappears, and the destructive metamorphose of the tissues becomes lessened. The statement here given of the effects of alcohol given in Typhus, to the exact amount re- quired by the condition of the blood, in narcotic doses, is home out by clinical observation, and is independent of any theory as to the cause of Typhus. It is not at all improbable that the theory of contagious disease, that each such disease owes its existence to a special living organism, and not to an orga- nic poison, may ultimately prove to be correct. ( 35 ) 1. The premonitory stage of diarrhoea. 2. The stage of collapse. 3. The stage of consecutive fever. The stage of collapse exhibits the following symptoms : — vomiting or purging ; muscular cramps ; suppression of bile and urine ; lowering of body temperature to 95° F. ; extreme prostration of strength ; extremities pulseless ; and face Hip- pocratic. When death occurs during collapse, the following symp- toms are usually found, on careful examination of the corpse. The temperature rises to 103° F. ; the muscles give out their characteristic susurrus CCC, and exhibit spontaneous move- ments ; the whole train of symptoms producing the effect of a ghastly attempt at resurrection.* In this disease we have phenomena respecting animal heat, the very reverse of those found in Typhus fever ; the body performing one vertical mile short of its daily work, instead of one mile in excess. The prostration of strength resulting from this deficient combustion is so great, that death is often caused by bringing the patient to hospital in a cab instead of upon a stretcher, by his walking up a dozen steps into his ward, and sometimes even fatal results have followed a sudden effort to sit up in bed to vomit. The rise of temperature after death, and the continuance of muscular susurrus and motion, tend to prove that the im- peded circulation which is the prominent symptom in Cholera collapse, is due to constriction (probably vasomotor nervous) of the capillaries — in consequence of which the muscles are deprived of their supply of freshly oxidised^ blood, the result * It is startling, on making a post-mortem examination of a cholera patient alone, and by candle light, to witness, on the first free incision of the scalpel, the hand of the corpse rise slowly from its side and placed quietly across its breast. c2 ( 36 ) of which is necessarily contraction, and cramp, which produces the excessive agony that •characterizes this disease. All authorities on Cholera, whether their object be to " im- pede" or to "assist" Nature, are agreed that medicines, whether astringent or purgative, are not only useless, ,but dangerous in the stage of collapse. It is useless to give alcoholic fuel to restore the loss of animal heat, for there is no circulation to cause the oxidation of the hydrocarbons. It is equally useless and more dangerous to give opium, to check the remaining purging that exists ; for if vomiting have ceased, your acetate of lead and opium pills lie, as if in the stomach of a corpse, and at the termination of collapse, your patient enters upon the consecutive fever, with perhaps a dozen grains of opium in his stomach, placed there like an explosive shell by your ill-timed zeal, and rapidly passes into a comatose condition, from which he never for a moment ral- lies. His death is always accredited by the Kegistrar to cholera morbus, and not to opium. Purgative sand emetics* in Cholera collapse effect the same object as opium, but with greater rapidity. In the stage of blue collapse, the chances of life and death are almost exactly equal, and the slightest additional loss of force turns the wa- vering beam on the side of death. The effects of a brisk pur- gative or emetic (if they act) upon a patient, unable to climb a dozen steps, or sit up for a quarter of an hour, without fatal syncope, may be easily imagined ; and the use of them can- not be justified by any arguments borrowed from right reason, A remarkable though transient improvement takes place in Cholera collapse by the injection of warm water (brought to the specific gravity of serum by the addition of mineral salts) into the veins or bowels ; the patient loses the cramips, feels * Wheii mustard ia used, its conservative effects as a stimulant sometimes counteract its destructive effects as an emetic. < 37 ) that he is about to recover, speaks to his friends, and often transacts whatever business is necessary ; but speedily falls back into collapse. The improvement in his condition is al- together due to the temperature of the fluid injected, which supplies for a brief period the deficient animal heat, permits a partial oxidation of the blood, restores the capillary circula- tion in the muscles, and so destroys their cramp ; and by sup- plying the deficient work required, removes for the moment the fatal prostration of strength. Any one who has witnessed the remarkable effects of warm liquids thus injected in Cho- lera collapse must feel that recovery would be certain, if the improvement could by any possibility be made permanent. Our hopes for the future, as to the treatment of Cholera, lie, as I believe, in the direction of supplying to the body, di- rectly, its lost animal heat. I have witnessed the happiest re^ suits from an injection of warm salt water into the bowels, assisted by hand friction of the surface with turpentine and* chloroform, and the application of bags of hot salt along the- spine : in cases treated in this manner, we may expect to wit- ness cessation of niuscular cramp, restoration of perspiration to the skin, with increase of capillary circulation, and finally, to reward our efforts, a return of the excretions of urine and bile ; when these reappear, all vomiting and purging cease, and our patient is almost cured. After recovery, the contrast between the Cholera and Fever patient is as great as it was during sickness. The fever patient has been overworked for 9 or 1 5 days without a suit- able supply of food, and when convalescent, experiences a complete exhaustion of strength that lasts for many weeks. The Cholera patient, on the other hand, has been prevented from working, by constriction of the capillary vessels, caused by the absorption of the cholera poison,* andfeels, on recovery, * Whatever this may be, its period of incuhatiou is 49 hours; that of fitryohmne is 22 miuutes. ( 38 ) much like a man that has been half drowned, while the Fever patient resembles a man that has been half starved : the one is able to return to his work in the course of a few days, the other, only after the lapse of as many weeks. There are two popular superstitions prevalent among medical men respecting Nature, which yearly slaughter he- catombs of victims ; viz., that Nature is simple in her opera- tions, and beneficent in her intentions ; she is often both sim- ple and beneficent, but at other times she is unquestionably both complex and malevolent. An Egyptian fable informs us, that the votaries of Goddess Nature were divided in opinion as to whether she was transcendently beautiful, or hideously ugly ; and that, in order keep up this difference of opinion which suits her pur- pose, she always wears a thick veil over her face. " For, with a veil that wimpled everywhere. Her, head and face were hid, that mote to none appear ; That some do say, was so by skill devised, To hide the terror of her uncouth hue From mortal eyes that should be sore agrised ; For that her face did like a Lion show, That eye of wight could not endure to view ; But others tell that it so beauteous was, And round about such beams of splendour threw. That it the sun a thousand times did pass. Nor could be seen, but like an image in a glass." Before trusting Nature in the matter of Cholera, and pro^ ceeding to help her, it would be well to inquire whether she intends to cure the patient by her evacuations, or to put him into his coffin. For myself, I greatly mistrust her, and would wish to ask, previous to assisting her, whether she is really my Mother, or only my Stepmother. Our experience in Dublin has shown, that no more effectual mode of shortening life could be devised in Cholera than the " eliminant" treatment; and it was accoidingly abandoned as soon as tried in that city. ( 39 ), It is much to be regretted, that an authority so deservedly- held in high repute as that of Sir Thomas Watson, can be now- quoted in favour of the treatment of Cholera, by the maxim,, similia dmilibm curantur. So far as Dr. Watson has informed': us, his change of opinion rests upon the statements of others,, and not upon his own experience. He has suddenly become an advocate of the castor oil, rhubarb, calomel, and elimi- nant treatment of Cholera, and writes as follows : — "When I last spoke on this subject in these lectures, I stated that the few recoveries which I had witnessed had all taken place under large and repeated doses of calomel, but I eould not venture to affirm that the calomel cured them. At present, I am much disposed to believe that by its cleansing, action, the calomel may have helped the recovery ; and after all that I have since seen, heard, read, and thought upon the- matter, I must confess that in the event of my having again to deal with the disorder, I should feel bound to adopt, in its- generality, the evacuant theory and practice." Sir Thomas Watson omits to add, that the cases here re- ferred to were only six in number, of whom three died, and three recovered ; which is exactly what might have been ex- pected if he had not interfered at all. Cholera from Bengal visits these islands, at intervals of about 1 7 years, and it is muck to- be feared, that on its next outbreak hundreds of patients will be sacrificed,, in obedience to the dogma that asserts it to be our duty to assist Nature. C. Diabetes mellitus. — This disease furnishes us with one- ©f our best proofs that all the chemical changes, by means of which work is produced, take place in the blood and not in the tissues of the body; and, at the same time,, an examination, of its phenomena explains satisfactorily the regimen and diet which has been found, by experience, most suitable to the diabetic patient. I shall illustrate the disease by a case which, was placed under my controul, by Dr. Stokes, some years ago. ( 40 ) A young man (jet. 20) named Murphy, suffered from fever (Enteric?) in November, 1859, and on recovering, became diabetic ; he was admitted into the Meath Hospital, in Octo- ber i860, where he remained, under my observation, until his death on the 12th January, 1861. He was allowed, for nine weeks, to eat as much as he liked of certain kinds of food, which were varied, week by week, to suit his wants, my object being to obtain, if possible, the natural constants of the disease, undisturbed by external in- terference ; the only medicine used by Dr. Stokes's order being opium, to produce sleep, and a little kreasote occa- sionally, to promote digestion. As the details of this experi- ment have been fully published, I shall confine myself to the final results. His food and excretions were analyzed from week to week, so as to determine the total quantities of sugar- forming and urea-producing food, as well as the sugar and urea actually excreted. During six of the nine weeks, the sugar excreted was in excess of the sugar ingested ; and the means of the whole nine weeks' daily excretion and ingestion of sugar were. Sugar excreted, 9773 E^^- Sugar ingested 9321 ,> Diff 452 grs. During two of the nine weeks of observation, the urea ex. creted was in excess of the urea ingested ; and the means of the whole nine weeks' daily excretion and ingestion of urea were. Urea excreted, . . . . . 1182 grs. Urea ingested, 1349 „ The foregoing facts illustrate strikingly one of the promi. nent symptoms of Diabetes, viz., the canine appetite; the quantity, both of sugar-producing and urea-forming food con- sumed is more than double what is necessary to maintain a ( 41 ) vigorous labourer in perfect health. An examination of the excretions explains the other prominent symptom of Diabetes ; viz., the complete prostration of strength in the patient, not- withstanding the great amount of food consumed. In a state of health, food produces three excretions only, viz., urea, carbonic acid, and water ; in Diabetes, the farina- ceous foods appear in the excretions as sugar, and not as car- bonic acid and water ; and the work necessary to maintain animal heat must be provided altogether at the expense of flesh food, which is the very form of food least fitted to main- tain it. The Diabetic patient resembles a racing steamboat on the Mississippi, whose supply of coals is exhausted, and whose cargo furnishes nothing better than lean pork hams, to throw into the furnace, to maintain the race. It cannot be wondered at that our poor patient, under such disadvantageous condi- tions, fails to keep in the front. , Let us compare together the minimum of work necessary to keep Owen Murphy alive, with the work actually supplied to him by the food digested. I. I have already stated that Dr. Eanke found 660 grms. of carbonic acid excreted daily, in the extreme fasting condition, when he weighed 67 kilos. Now, since 660 grms. = 10185.35 grs. 67 kilos. = i47'7i lbs. we find 69 grs. per lb. of body weight, as the minimum ex- cretion of carbonic acid, consistent with continued life. This quantity of carbonic acid represents a work generated by its production that would lift its corresponding pound of body weight through a height of 6 O 772 60 X — X 8080 X - X — — = 5.716 miles. ^22 5 7000 X 5280 Under ordinary conditions, the greater part of this carbo- ( 42 ) nic acid and work is produced by the digestion of farina- ceous food ; but since, as we have seen, the farinaceous food is excreted as sugar in the Diabetic patient, and therefore does no work at all, the whole of the foregoing work must be done by the digestion of other kinds of food. I have already shown that it follows from Lavoisier's ex- periments (confirmed in a remarkable manner by those of Kegnault), that the work done by the combustion of carbon in the body is to the work done by the combustion of hydro- gen in the proportion of 9068 to 3024, almost exactly 3 to i ; hence we have the work done, by Owen Murphy, as a mini- nimum in health — Due to carbon 5 -7 16 miles. Due to hydrogen, . . . 1.905 „ 7.621 miles. This result is somewhat in excess of the truth, for the same reason that the calculated digestion coefficient of proteine is in excess of that found by Frankland from experiment ; for the combustion coefficients of carbon and hydrogen, in organic compounds, are slightly less than when free. If we are per- mitted to reduce 7.621 miles in the same proportion as in the digestion of proteine, viz., 48 to 43, we shall find — Owen Murphy — minimum of work consists of body weight lifted through, 6.83 miles. Let us now. compare this minimum with the work actu- ally performed by him when suffering from Diabetes, by the digestion of flesh food and production of urea. 2. I have already shown that the work produced by the formation of 501.28 grs. of urea is 704 ft. tons, by calculation from the composition of proteine and urea ; this result should be reduced in the proportion of 48375 to 43155, in order to obtain the work given by Professor Frankland's experiments. ( 43 ) Making this reduction, we find that 500 grs. of urea corre- spond to 626.3 ft. tons of work, or 100 grs. urea to 125.26 ft. tons ; or, in other words — Every four grains of urea excreted correspond to Jwe tons lifted through one foot. '' Owen Murphy excreted, on an average, 11 82 grs. of urea, daily, during nine weeks — which, by the foregoing rule, are equal to 1475 ft. tons = Murphy x a; ; where w represents in miles the height through which the pa- tient could be lifted by the work done per day ; and is equal to 1475 X 2240 ., x = — = 6.00 miles. 93.56 X 5280 This result is almost exactly equal to that already found as the minimum consistent with continued life, and explains in the most satisfactory manner the complete prostration of the patient, notwithstanding the consumption and digestion of more than double the usual quantity of flesh food. In corroboration of the foregoing conclusion, I may men- tion that Murphy's temperature was found to be constantly 2° F. below that of other patients (chronic) placed in the same ward, and, in other respects, under similar conditions. His unfavourable symptoms (so long as his powers of di- gestion were not impaired) were invariably alleviated by the free use of flesh food and fat, the latter being, instinctively, preferred by him ; so much so, that during the delirium that preceded his death for 24 hours, he raved incessantly about " fat, roasted fat, which the angels of heaven were preparing for him." I have studied many other cases of Diabetes meUitus, and found similar results in all ; but I feel it to be unnecessary to describe them, as one well ascertained train of phenomena. ( 44 ) carefully observed and recorded, is quite sufficient to esta- blish the order of nature. Conclusion. I have, now, Mr. President and gentlemen, to apologise for the length of time during which I have spoken, and to thank you for the patience with which you have listened to me. I am well aware how much I am indebted to your kind- ness, for I laboured under two serious disadvantages in ad- dressing you : in the first place, I had undertaken a task beyond my strength ; and again, my address is made, shortly after you had, like myself, been charmed and instructed by the luminous, learned, and eloquent oration of Professor Rol- leston. I felt confident, however, that I possessed one advan- tage that he did not ; I was a stranger in Oxford, and believed that my faults in matter and style would be leniently criticised ; in this expectation, I am happy to say 1 am not disappoint- ed ; and again I thank you for your kindness. Two other advantages I share with him, which have contributed to his address as much as to my own — a profound respect and reve- rence for all honest labourers in search of truth, whether they have preceded us by 20 years or by 2000 years ; and an un- wavering confidence and faith in the future that lies before the Science of Medicine. We traverse a sea, mapped with imperfect charts, but assured of a safe guide in our compass and stars ; but we cannot afford to neglect a single rock or shoal, buoyed for us by the skill and care of those that have preceded us. Let us follow their example, and mark with conscientious care, for our successors, the dangers we ourselves discover and escape. Assembled, as we are, within the halls of the University of Oxford, the centre and heart of all that is intellectual and re- ligious in the life of England ; an University that borrows its ( 45 ) accurate Logic, as well as its refined Ethics, from the lips of Aristotle ; that reverences Euclid as the fountain and source of its elegant Q-eometry ; and sits at the feet of Homer, Pindar, and Eschylus, to learn its poetry ; we need not fear that Hip- pocrates and Galen will ever want admirers and students ; but the Oxford of to-day has taught us, what many did not anti- cipate, that she is equally ready and skilful, as she has proved herself to be in cultivating Literature, to devote her vast in- tellectual energies to the encouragement and developement of^the Natural Sciences, based upon the solid, and only per- manent foundation of Mathematical research. The efibrts made within the last few years by Oxford, to encourage within her walls the Mathematical and Natural Sciences, have won for her the respect, and warmed towards her the hearts of all that search for truth in the study of Nature. Our brothers in Oxford, like the Athenians at Syracuse, have gone on board the fleet, while we watch them from the shore, sympa- thizing in the sea fight ; as they win, we shout ; when they fail, we weep. Long may the union of the far distant, but never to be forgotten Past, with the Hving Present, that now exists in Oxford, continue. No science, no profession, can benefit so much by it as that of Medicine, THE END. Cornell University Library QP 141.H37 Address on the relation of food io'^o'^' 3 1924 003 166 653