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Infant Diet 
 
 BY 
 
 A. JACOBI, M.D., 
 
 CLINICAL PROFESSOR OF DISEASES OF CHILDREN, COLLEGE OF PHYSICIANS AND 
 SURGEONS, NEW YORK. 
 
 REVISED, ENLARGED AND ADAPTED TO POPULAR USE 
 
 MAEY PUTNAM JACOBI, M. D. 
 
 NEW YORK: 
 
 G. P. PUTNAM'S SONS, 
 
 Fourth Avenue and Twenty-thir;d Street. 
 
 1874. 
 
Entered according to Act of Con gross, in the year 1374, by 
 
 G. P. PUTNAM'S SONS, 
 In the Office of the Librarian of Congress, at Washington. 
 
PREFACE BY THE EDITOR. 
 
 "What should be the nature of a popular essay ? To 
 judge by the multitude of little books that are lavished 
 upon young mothers to help them in the care of their 
 children, one thing is supposed to be fundamental — 
 theory, or an explanation of scientific basis for the pre- 
 cepts laid down, must be rigidly avoided. " However 
 this may be," observes Fonssagrives, " the physiological 
 theory is of no importance to the mother ; all that con- 
 cerns her, is the fact." 'Now we assume, contrary to 
 this dictum, that the theory of a fact. does concern every 
 intelligent person who is interested in its application. 
 We consider that a popular essay must differ from a 
 scientific treatise — 1st. By the use of non-technical lan- 
 guage, and consequently by the sacrifice of the concise 
 style that enahles so much to be concentrated in so few 
 words. 2d. By a careful explanation of things assumed 
 
IV PREFACE BY THE EDITOR. 
 
 to be known by persons conversant with the science, and 
 to whom such explanation would therefore be imperti- 
 nent. 3d. By restriction within the limits of what is 
 already positively assured to science, and by the absence 
 of the new researches or the original criticism which 
 alone constitute the raison d'etre of a book professing 
 to be scientific. These conditions narrow the scope of 
 a popular essay, but do not necessarily render its direc- 
 tion different from any other that professes to convey 
 information. The information that can be given is in 
 proportion to the technical abbreviations which may be 
 employed, and inversely to what is already known ; and 
 hence, as the popular reader is presumably ignorant of ■ 
 the* subject-matter, only a comparatively small amount 
 of knowledge can be conveyed to him. But what is 
 told should be the same in kind as what is told to the 
 scholar. Few women seem to be aware of the insult 
 implied in the assertion " that the theory is of no im- 
 portance to them." Of whomsoever this assertion may 
 be truthfully made, it must be said that he is destitute 
 of the highest characteristic of an intelligent being — the 
 desire, namely, " to understand himself and the things 
 around him." It is true that, without technical educa- 
 tion, no mother can fully understand physiological laws, 
 
PREFACE BY THE EDITOR. V 
 
 nor be able to deduce from them all the practical rules 
 that are necessary for guidance in health, and still less 
 in disease. But, like the intelligent passenger on a 
 vessel, who learns how to. read the chart and to foresee 
 the directions and incidents of the voyage, even while 
 submitting to the control of the captain, so the mother 
 may learn the general plan of her child's life, its future 
 course, and the accidents that beset it, and, in regard to 
 the details to which her attention 'is called, learn much, 
 if not all, of their scientific relations. For these mean 
 simply the exact relations of things to each other, of 
 effects to causes, of appearances to underlying conditions, 
 of actions to organs, of vital phenomena to the physio- 
 logical laws of the body in which they occur. 
 
 This little book is not a mother's manual, nor a 
 treatise intended to exhaust the vast topic of the devel- 
 opment of infant life. To understand only a small part 
 of what is known about that, the mother must consult, 
 not one little volume*but many big books. Of all the 
 questions that might be asked in relation to the child, 
 we only propose to answer one — namely, " What shall 
 it eat ? " But this is fundamental to all others, as is to 
 the farmer the nature of the soil whence his seed may 
 obtain the materials for its growth. The roots of the 
 
VI PBEFACE BY THE EDITOE. 
 
 plant lie outside its body, but in the infant's body the 
 roots are inside, lining in infinite number the walls of 
 the stomach and intestine, whence they reach down into 
 the fluids that fill these canals, and draw up nourish- 
 ment to be absorbed into the blood So long as the 
 food is still in the digestive tube, it is as much outside 
 the body as are the salts in the earth penetrated by the 
 rootlets of plants. Yet as the composition of that soil 
 will determine the kind of plants that may spring from 
 it, here wheat, there barley or oats — here the pine, there 
 the luxuriant olive — so upon the substances that are 
 introduced into the alimentary canal, and on the chem- 
 ical changes that take place there, largely depends the 
 character of all the tissues of the body. In a plant, 
 where the life is purely nutritive, that is, where there are 
 no functions involving muscles or nerves, it is much 
 easier to study the relations between the food and the 
 tissues, than it is in an animal, in whom these relations 
 are so incessantly modified by the influence of the ner- 
 vous system. We analyze what is absorbed by the 
 leaves and the roots, what is exhaled from the leaves 
 again, and finally the substance of which the plant is 
 composed, and we can then judge pretty well of the 
 nature of the changes through which the food has 
 
PREFACE ET THE EDITOR. VU 
 
 passed during the building up of the body of the plant. 
 But in an animal, the action of the nerves and mus- 
 cles determine other changes than those needed for the 
 transformation of food into tissues, and on this account 
 the problem is greatly complicated. Now, in comparison 
 to the life of the adult, the life of a baby approaches to 
 that of a plant. It has, indeed, a nervous system, and 
 one exquisitely susceptible to influences brought to bear 
 upon it from without, and especially to those that affect 
 the two great surfaces of the body, the skin and the 
 mucous membrane of the digestive canal. But this ner- 
 vous system does not, like that of the adult, originate 
 actions whose intensity is constantly liable to disturb the 
 processes of nutrition. Thus, in an adult, dyspepsia is 
 most frequently induced by exhaustion of the nervous 
 system consequent upon over-work, by fatigues, depress- 
 ing emotions, anxieties, etc. These are all as foreign 
 to the tranquil life of the child as to the slumbering 
 consciousness of wood anemones. But in the child, the 
 same dyspeptic symptoms will be caused by ill-assorted 
 food, acid fermentation in the stomach and bowels, and 
 the nervous system, blameless as a cause of the disease, 
 will suffer so violently from its effects, that life may be 
 destroyed in convulsions. 
 
Till PREFACE BY THE EDITOR. 
 
 On this account, the food in children is, relatively to 
 other things, of more importance than the food of adults : 
 also their health is more readily affected, their diseases 
 more readily controlled, by substances which determine 
 in the digestive canal known chemical reactions; whereas 
 in adults we are more often obliged to arrive at these 
 same results indirectly, by means of agents that exercise 
 their first influence on the nervous system, and whose 
 chemical reactions are too little understood to be utilized. 
 
 In the following pages we endeavor to set forth some 
 of the more assured facts in the possession of science 
 in regard to the chemical changes that take place in the 
 infant economy during the processes of nutrition, and in 
 regard to the means of averting morbid alterations in 
 these changes. 
 
INFANT DIET. 
 
 There was a time when no historical essay, either 
 systematic or monographical, could be written without 
 reference to Adam and Eve. With similar pertinacious 
 appeal to first principles, have authors of treatises on the 
 diet, physiology, or pathology of infants or children, con- 
 sidered themselves bound to prove by multitudinous facts, 
 that breast-milk is the indispensable food for newborn or 
 for young infants. Now there are some truths which 
 ought by this time to be taken as axioms, and whose 
 fresh demonstration seems to me superfluous. I shall 
 take it as granted that mother's milk is the most ap- 
 propriate food for an infant in all its stages of gradual 
 development; that weaning ought not to take place 
 before the infant and its digestive organs are sufficiently 
 prepared for more complicated nutrition ; that the grad- 
 ual changes in the constitution of mother's milk are 
 naturally adapted to the successive requirements of the 
 growing infant ; that, as a rule, the first indication of 
 the necessity of adding artificial food to breast-milk, or 
 
 T* 
 
10 INFANT DIET. 
 
 replacing the latter by the former altogether, is offered 
 by the appearance of the first teeth ; that, when breast' 
 milk is insufficient, food should be added or substituted 
 which, as nearly as possible, resembles breast-milk. 
 
 Were Nature always adequate to the transaction of 
 her own business and the fulfilment of her own wishes, 
 she might be left to herself without interference, and we 
 doctors especially would find our occupation gone. As 
 scientists we should continue to study her processes and 
 try to comprehend her laws; but then we should feel as 
 little necessity for modifying the one or the other, as 
 for changing the orbit of the planets, or the path of the 
 earth around the sun. We agree, at all events, to con- 
 sider perfect such parts of the universe as lie entirely 
 beyond our control ; and "even when this agreement is 
 purely conventional, it at least secures resignation to 
 the inevitable. 
 
 In regard to the -details of .human life, however, we 
 are at once more skeptical and more hopeful : the imper- 
 fections and failures in the unassisted working of natu- 
 ral laws are forced more conspicuously upon our atten- 
 tion, and we are more willing to admit their existence, 
 because we feel more able to control their consequences. 
 An excess of optimism is here extremely prejudicial, for 
 it tends to arrest criticism and to paralyze efforts which 
 are really needed to avert disaster. Eloquence is well 
 expended upon the beauty and. advantages of maternal 
 
INFANT DIET. 11 
 
 nursing, when this may be carried on in suitable condi- 
 tions ; but it is very certain that these conditions are 
 often extremely unsuitable, and that the mother's milk 
 may be as unreliable in quantity, or as widely removed 
 in quality from the physiological type of nourishment 
 required by the infant, as could be the most badly pre- 
 pared artificial food. Sometimes the chemical compo- 
 sition of human milk is altered, and the proportion 
 between its different constituents, salts, butter, cheese, 
 sugar, water, changes to that characteristic of the milk 
 of other animals. In this case, the nursling at the breast 
 is exposed to precisely the same inconveniences as a 
 bottle-fed child, brought up on alien food. In other cases, 
 the alterations in the milk, through inappreciable to our 
 chemical analysis, is even more injurious than those 
 which are. It is caused by the existence in the mother 
 of certain constitutional diseases, which affect the milk, 
 as every other secretion of the body, and may render it 
 a slow poison for the child. Or, without positive dis- 
 ease, the constitution of the mother may be weakly, and 
 deteriorate still further under the nursing. The mater- 
 nal milk then tends to confirm or increase the vices of 
 nutrition already conveyed to the child by way of 
 inheritance. It is often urged as an argument for the 
 expediency of maternal nursing whenever the mother 
 has a drop of milk in her breasts, that the mother's 
 milk must be the more easily assimilable than any other 
 
12 INFANT MET. 
 
 by the child, because it is elaborated from the same 
 blood as has furnished the materials for building up the 
 child's body. This very resemblance is a disadvantage 
 in the cases supposed, where it is desirable to counteract 
 the original tendencies of the constitution, and to build 
 up tissues in the child as different as possible from those 
 of the mother. It is, however, often true that a child 
 will assimilate its mother's milk better than that of any 
 other woman, and will therefore thrive better upon it, 
 although it be in itself less nutritious. It is well known 
 to physicians, but much less well known than it should 
 be to the public, that the nutritious value of food 
 depends partly on its composition, partly on the facility 
 with which it may be absorbed and assimilated; and 
 circumstances that favor this assimilation may some- 
 times increase the nutritive value of the less well-com- 
 posed food over that of the better. But cases are, on 
 the whole, exceptional, where the milk of a weakly 
 mother is really more advantageous for the child than 
 that of a healthy wet-nurse or than suitably prepared 
 artificial food. Many a mother raises at her own breast 
 sickly, bloated, rachitical children, until finally one is 
 born that she is quite unable to nurse : then for the first 
 time appears in the family a noisy, ruddy, muscular baby. 
 There- are two other conditions, besides those enu- 
 merated above, which contraindicaite maternal nursing ; 
 namely, the occurrence in the mother of either menstru- 
 
INFANT DIET. 13 
 
 ation or pregnancy. These are not so rare as might be 
 supposed from some statements, or from the habit which, 
 prevails among many mothers, especially of the poorer 
 class, of prolonging lactation in order to avoid the recur- 
 rence of pregnancy. An English writer has even advised 
 working mothers to nurse their children during four 
 years, so that, on the one hand, the children may be fed 
 nutritiously and economically, and on the other hand, the 
 mothers may be saved from the strain of excessive child- 
 bearing, and society from the evils of over-population. 
 This philanthropist does not reckon upon the exhaustion 
 occasioned by excessive lactation, and which, as will be 
 presently shown, profoundly deteriorates the nutritive 
 character of the milk. But, apart from this consideration, 
 the value of the suggestion is greatly lessened by the 
 fact that many women retain their aptitude for concep- 
 tion throughout the nursing period, and the great major- 
 ity regain it at a definite time from the birth of the 
 child, whether the nursing be persisted in or not. 
 This time generally corresponds to that which may be 
 regarded as the proper duration for nursing — namely, 
 from nine to twelve months; but the epoch may occur at 
 four, five, or six months, or may be deferred to eighteen, 
 or later. On the other hand, it often happens that 
 women who do not nurse, do not recover their aptitude 
 for conception until six or eight months after the birth 
 of a child, and are therefore, in this respect, in the same 
 
14: INFANT DIET. 
 
 condition as nursing mothers. From these facts it 
 would appear that the activity of the mammary glands 
 does not absolutely determine a period of inactivity in 
 the ovaries and uterus, but rather corresponds to such a 
 period, that is self-determined, and variable in each indi- 
 vidual case ; — that in many cases, it is true, this inapti- 
 tude seems to be increased by the activitj 7 of the other 
 organs of the reproductive system, the mammary glands ; 
 but even this influence, which sometimes does not exist 
 at all, is always restrained within fixed limits. Beyond 
 these limits, the voluntary stimulation of the glands by 
 keeping the child at the breast may indeed secure the 
 secretion of some kind of milk; but the ovaries and 
 uterus regain their independence, menstruation may 
 return, or a pregnancy occur. Indeed, it is not abso- 
 lutely rare to find women menstruating, nursing, and 
 pregnant, all at the same time. We have here no statis- 
 tics to quote, but we believe that, except in countries 
 where the institution of polygamy favors the complete 
 isolation of the woman during the period of lactation, 
 the continuance of this function beyond twelve months 
 has, in the majority of cases, no effect upon preventing 
 the occurrence of a new pregnancy. 
 
 It is worth while to go back, and analyze some of 
 the conditions which have been enumerated as rendering: 
 maternal nursing undesirable or impossible. 
 
 Women of the most various constitutions may be 
 
INFANT DIET. 15 
 
 unable to nurse from absolute deficiency of milk ; and it 
 is well known that a robust woman may fail completely, 
 while her fragile neighbor brings up at her breast a 
 thriving child. Health is a relative term, and the gen- 
 eral health of the body is quite compatible with defec- 
 tive development of one or more of its parts. Thus, 
 even well-formed breasts may contain diminutive milk 
 glands, whose imperfection is concealed by the abun- 
 dant adipose tissue lying under the skin. Again, the 
 glands may be sufficiently large, yet their activity be 
 continually interfered with by the irritable condition of 
 the nervous system. The secretion of milk depends 
 on the equable flow of blood through the blood-vessels 
 of the glands, and this is maintained when the blood- 
 vessels stay open to just the right degree. The blood- 
 vessels are encircled by rings of muscular fibre, and 
 when these are made to contract by irritation of the, 
 nerves going to them, the blood-vessels are spasmod- 
 ically closed, the circulation of the gland is disturbed, 
 and the secretion of milk arrested. On this account, 
 depressing emotions, and irritative excitement, especially 
 anxiety about nursing, will stop the flow of milk, and, 
 if long continued, may cause it to entirely " dry up." 
 The stimulating effect on the secretion of milk exer- 
 cised by the agreeable emotions, is well known to every 
 mother. When the whole nervous system is equably 
 stimulated, there is no such undue concentration of 
 
16 INFANT DIET. 
 
 stimulus upon the nerves of the glands as may cause 
 irritation with spasmodic closure of the blood-vessels. 
 Again, the secretion of milk, which takes place chiefly 
 when the child is put to the breast, demands, like all 
 secretions, a certain influx of nerve force, or innervation, 
 to the gland. Whenever the nervous system is weak, 
 the intermittent action of nerves is attended by pain; 
 .and hence the act of nursing may occasion severe neu- 
 ralgic pains through the breast and back, quite inde- 
 pendent of cracks in the nipples, to which they are 
 generally attributed. 
 
 A third evil influence of an excitable nervous tem- 
 perament may be manifested in the quality of the milk, 
 which, under violent emotions, may be so altered as to 
 become a positive poison to the child. Generally, the 
 effects of such alteration are confined to digestive dis- 
 turbance, to vomiting, colic, purging. But in some rare 
 cases, whose reeord is famous, a child put to the breast 
 of a woman still agitated by violent excitement, has 
 been seized with convulsions, or has even died suddenly, 
 without the warning of any symptoms whatever. In 
 these cases a virulent ferment seems to have been gene- 
 rated in the milk, analagous in the intensity of its action 
 to that formed in the saliva of hydrophobic dogs, and 
 whose malignity varies according to its abundance and 
 to the mass of milk that had been decomposed under 
 its influence. 
 
INFANT DIET. 17 
 
 For all these reasons, a woman with a markedly 
 nervous temperament is generally unsuitable for the 
 office of nursing; since her milk is liable to become 
 deficient in quantity or perverted in quality. 
 
 Again, though the mother have plenty, the child 
 may be deprived of milk from inability to nurse ; in 
 other words, on account of conditions which interfere 
 with the mechanism of suction. Their precise influence 
 is to be appreciated by reference to its details. "When 
 the child seizes the nipple, the lips, fitting accurately 
 around it, close the cavity of the mouth in front, while, 
 behind, this cavity is closed by the soft palate, which 
 falls like a curtain upon the root of the tongue. The 
 tongue arches so as to touch the roof of the mouth, and 
 the cavity is thus completely filled up, as the cylinder 
 of a pump is filled by the piston. When the child 
 begins to suck, the tongue is drawn back, just as the 
 piston would be, and for the same purpose, to create a 
 vacuum in the space left between its tip' and the lips. 
 Into this vacuum the milk is forced from the nipple by 
 the pressure of the atmosphere on the breast. As soon 
 as the space is filled, the milk is thrown to the back of 
 the mouth by the tongue, which abandons for this pur- 
 pose its office as piston, the soft palate is lifted up to 
 a level with the roof of the mouth, thus closing the 
 communication with the nose, and the milk falls into 
 the throat, there exciting automatic contractions of the 
 
IS INFANT DIET. 
 
 muscles of the pharynx, that occasion a distinct sound 
 of deglutition. This movement of deglutition alternates 
 therefore with that of suction. 
 
 Now, if the child have a harelip, the nipple cannot 
 be accurately embraced, the cavity of the mouth is left 
 open in front, and the vacuum cannot be formed. In 
 cleft palate, a fissure runs along the roof of the mouth, 
 opening a communication with the nose, and the vacuum 
 is again spoiled, because the cavity is left open above. 
 "When the tongue is tied, i. e. bound down to the floor 
 of the mouth, behind the gums, it cannot retract suffi- 
 ciently to fulfil the office of piston. In all these cases, 
 therefore, the vacuum is imperfect, and therefore the 
 milk is imperfectly pressed out of the milk ducts into 
 the baby's mouth. The difficulty is purely mechanical. 
 But again, in certain cases of profound debility, such as 
 occur iii children that have been born prematurely, the 
 child may be incapable of the muscular effort necessary 
 to close the lips and move the tongue, and nursing is 
 therefore again rendered impossible. 
 
 The so-called " vital " changes in the chemical com- 
 position of the milk, dependent on distinct disease, are 
 especially to be dreaded when the mother is affected with 
 consumption, syphilis, epilepsy, or chronic eruptions. 
 When the mother has a flabby, lymphatic constitution, 
 without actual disease, or when there is anemia, i. e. im- 
 poverishment of the blood, induced by over-work, insuffi- 
 
INFANT DIET. 19 
 
 cient food, or prolonged lactation, tlie solid constituents of 
 the milk are generally diminished. The milk of an anemic 
 woman who had been bled several times during preg- 
 uaney, showed a marked diminution of caseine and sugar, 
 with an increase of butter. This latter fact is quite re- 
 markable, and of importance, because the nutritive value 
 of milk is generally estimated by the proportion of fat 
 alone. As will be presently shown, the fat in milk is 
 formed in the cells lining the ducts of the glands, from 
 the caseine and sugar. In many cases of perverted 
 nutrition, an excess of albuminous and saccharine mate- 
 rial is converted into fat, and it is possible that the excess 
 of fat found in this analysis was due to such morbid 
 metamorphosis. In another anemic woman, who had 
 suffered from uterine hemorrhages, the caseine, butter, 
 and sugar were all diminished, together with some of the 
 salts (phosphates). In other words, the milk was more 
 watery — just as the blood is after hemorrhage. Both 
 the children were rickety. In a third case, where the 
 child was extremely rickety, and died on the fifty-third 
 day, the sugar was in normal proportion, but the caseine 
 and butter were diminished, and there were only traces of 
 earthy salts. 
 
 Analyses of milk are so rarely made in comparison tc 
 the frequency with which its altered composition is evi 
 dently the cause of ill health in the nursling, that we dc 
 not yet know precisely when and how it is modified 
 
20 INFANT DIET. 
 
 Still some facts have been acquired, and may be stated as 
 follows : — The water is in excess, i. e. the solid constitu- 
 ents are diminished en masse, when the proportion of 
 water in the blood is increased — thus after hemorrhages, 
 artificial bleeding, in some kidney diseases, and in some 
 forms of anemia. The milk is less nutritious because 
 watered. The water is diminished, in forms of anemia 
 where the mass of blood is diminished ; in very hot 
 weather, causing excessive perspiration ; in fe'vers ; and 
 during menstruation, if that occur in the period of lacta- 
 tion. In the last case, the diminution depends on the 
 derivation to the uterus of blood from the blood-vessels 
 of the mammary glands, thus diminishing the supply from 
 which the water of the milk is to be transuded. 
 
 The quantity of caseine is, other things being equal, 
 in inverse proportion to that of the water, and is there- 
 fore increased in all the above cases. During menstrua- 
 tion, the cells of the ducts which secrete the albumen, 
 sugar, and salts from the blood, continue their function 
 even when less water transudes from the blood-vessels, 
 and hence the solid ingredients of the milk increase out of 
 proportion to the aqueous. The milk is said to be more 
 concentrated, resembles cow's milk, and is digested with 
 difficulty by the child for the same reason as the latter. 
 The quantity of caseine may be readily estimated by 
 curdling skimmed milk with acid, washing the curds 
 
INFANT DIET. 21 
 
 repeatedly to free them from sugar and salts, drying, and 
 weighing the residue. 
 
 Deficiency of butter frequently occurs in poor, watery 
 milk, found in the breasts of anemic women, ill fed, or 
 debilitated from other causes. Yet, as we have seen, in 
 some such cases, there is an excess of butter in propor- 
 tion to the other solid ingredients ; but it is highly prob- 
 able that then the butter is not of normal quality, but 
 results from the fatty degeneration of the albuminous 
 ingredients of the milk. Albumen is very liable to be- 
 come converted into fat as a result of perverted nuta- 
 tion, and in this way the muscles of the limbs or the 
 muscular fibre of the heart becomes fatty, or " suffers fatty 
 degeneration." The same change may take place in the 
 albumen of the milk. 
 
 The butter of milk is not dissolved in the water of 
 milk, as are the caseine, sugar, and salts, but floats in 
 the form of microscopic round globules, called fat glo- 
 bules. These are very characteristic of milk, and upon 
 their variations in number or appearance are based the 
 most usual methods for estimating the richness of the 
 milk. It is they which give the peculiar opaque white- 
 ness to the fluid, and this is more marked in proportion 
 to their abundance. On this account, cow's milk, which 
 is very rich in butter, is extremely white and thick, 
 while human milk, which contains less butter and 
 more sugar, is bluish and semi-transparent. The milk 
 
22 INFANT DIET. 
 
 secreted immediately after childbirth has much fewer 
 fat globules than that which comes later. On the other 
 hand, it contains some large cells, filled with granula- 
 tions, and called colostrum corpuscles. These should 
 disappear from the milk within eight days after child- 
 birth : if they persist longer, the milk is rendered un- 
 healthy. When the milk has become unhealthy from 
 exhausting disease in the mother, these colostrum cor- 
 puscles sometimes reappear. 
 
 The fine granules contained in the colostrum cells 
 are fat granulations, while in the butter globules the 
 fat is collected into one large drop of oil, which com- 
 pletely fills the cell. The colostrum is an early stage in 
 the development of fat globules. The lactometer of 
 Donne is an instrument with which the number of fat 
 globules may be estimated from the color they give to 
 thin layers of milk. It is very important to remember 
 that milk may respond to this test, and yet be insuffi- 
 ciently nutritious from lack of other materials. The 
 deficiency of butter does, however, seriously impair the 
 nutritive value of the milk, for fats play a most impor- 
 tant part in the nutrition. When burned or oxidized 
 in the blood, they evolve a very considerable amount of 
 heat, nearly five times as much as meat, three times as 
 much as bread, and twice as much as sugar or farinaceous 
 food. This heat is as necessary for the growth of the 
 tissues in the baby's body as for the growth of seeds in 
 
INFANT DIET. 23 
 
 the ground. Again, when fat is mixed with albuminous 
 substances in the stomach, as with the caseine of the 
 milk, the digestion of the latter is facilitated. (Bous- 
 singault.) 
 
 When, therefore, there is not enough butter in the 
 milk, the caseine present is digested with more diffi- 
 culty, and the result is the same as if the caseine were 
 in excess. The baby, therefore, will vomit solid curds, 
 as if it were fed upon cow's milk. The same influence 
 of fat upon the metamorphosis of albuminous substances 
 is exercised in the blood : the plastic (building) mate- 
 rials, received from the food, cannot be converted into 
 the tissues of the body without the presence of fat. Fat 
 seems to be essential to the formation of new cells, whose 
 nucleoli always contain fat, and there is more in young 
 and rapidly growing tissues than in those whose growth 
 has been slackened by maturity. 
 
 It remains, therefore, in a soluble form, intimately 
 associated with the elements of the tissues ; and as these 
 begin to decay, the fat accelerates the chemical changes 
 which effect their decomposition, and hence the elimi- 
 nation of used-up material from the body. The ner- 
 vous system is the part of the body where nutritive 
 changes are the most rapid and complete, and it is here 
 that fat principally abounds and is most tenaciously 
 retained. From all this is evident the immense import- 
 ance of fat in the nutrition of the rapidly growing infant 
 
24: INFANT DIET. 
 
 body, and thus may be easily explained the emaciation 
 that takes place in babies nourished by milk in which the 
 fat globules are deficient. The function of sugar is part- 
 ly the same as that of fat, that is, it contributes largely 
 to the production of heat. Its heat-making power is 
 only about one-half that of fat, but, during its passage 
 through the body, sugar becomes partly converted into 
 fat, and then it serves precisely the same purposes as the 
 latter substance. Sugar is liable to ferment in the diges- 
 tive canal, especially in the mouth, if long retained there, 
 and then acids are formed which irritate the mucous 
 membrane. Many cases of sore mouth in bottle-fed 
 babies is due to the excess of sugar added 'to their food. 
 In human milk, the sugar is rarely in excess, although 
 this has been observed in the watery milk of anemic 
 women. (Routh.) It is much more often deficient. 
 The effects of such deficiency will be partly the same as 
 we have noticed when butter was deficient — for the reason 
 that sugar partly supplies the place of butter, and partly 
 is converted into it. But other substances that result 
 from the decomposition of sugar, are of importance in 
 many ways. Lactic acid is formed in the stomach, helps 
 to give acidity to the gastric juice, and thus assists in the 
 digestion of caseine. It will be shown further on that 
 the presence in the stomach of substances soluble in 
 water, as sugar, accelerates the digestion of insoluble sub- 
 stances, as caseine. (Schiff.) 
 
INFANT DIET. 25 
 
 When food is digested rapidly in the stomach, it is 
 thrown more rapidly into the intestine, and the peristal- 
 tic movements of the intestine are accelerated. But 
 when food arrives too slowly in the intestine, it is stim- 
 ulated too slowly to contract, and, to use the popular 
 phrase, " the bowels become sluggish." It is probably 
 in this way that milk in which sugar is deficient, fre- 
 quently becomes a cause of constipation in the child ; 
 and that, on the other hand, infantile constipation may 
 often be relieved by the addition of sugar to the food.* 
 The diminution of sugar frequently coincides with a sur- 
 plus of caseine. 
 
 The last constituents of the milk are the inorganic 
 salts, chloride of sodium and of potassium, phosphate of 
 potassa, iron and lime. In human milk all these to- 
 gether only amount' to two and a half parts in a thou- 
 sand, and at first sight it may be difficult to understand 
 how mineral substances, and in such minute quantity, 
 can be of any importance to the nutrition of the animal 
 body. ■ Yet each member of this group has a distinct 
 function to perform, and if it be deficient the child will 
 cease to thrive. 
 
 The chloride of sodium, or common salt, begins to 
 play its part as soon as it reaches the stomach ; for it is 
 
 * One or two scruples, about two-thirds of a teaspoonf ul, of loaf 
 sugar, are dissolved in two teaspoonf uls of tepid water, and given just 
 before nursing. 
 2 
 
26 INFANT DIET. 
 
 decomposed by the glands of the stomach into soda and 
 hydrochloric acid, the latter being the most important 
 ingredient in the gastric juice. (Beneke.) The salt, 
 therefore, both stimulates the glands to activity and fur- 
 nishes the material upon 'which they may act. In this 
 way it is a very powerful agent to increase the appetite. 
 When the hydrochloric acid has fulfilled its duties in the 
 stomach and passes into the intestine, it combines with 
 a part of the soda of the bile to form chloride of sodium 
 again, and this very reaction stimulates the secretion of 
 bile. The presence of chloride of sodium in the fluids 
 of the intestine regulates the diffusion of substances 
 through the blood-vessels of the intestinal villi into the 
 blood ; and when the salt has passed into the blood, it 
 again regulates the diffusion of material from the blood 
 to the tissues, and from the serum of the blood to the 
 blood corpuscles. The albuminous substances that must, 
 be absorbed from the intestine and finally fixed in the 
 tissues, find great difficulty in passing through the walls 
 of blood-vessels and of cells composed of material anal- 
 ogous to their own. These substances are called . " col- 
 loid," or "jelly-like," on account of this difficulty of 
 transfusion. On the other hand, substances that crystal- 
 lize, mineral salts, and especially chloride of sodium, dif- 
 fuse with great facility, and when they combine with 
 albumen, they carry the latter along with them, first into 
 the cells to build them up — then out of the cells, when 
 
INFANT DIET. 27 
 
 the cell substance has become effete and must be re 
 placed by new. This fact explains why all the solids and 
 fluids of the body contain salt ; for without it, no albu- 
 minous food could be taken up into the blood, nor pass 
 from the blood to the tissues requiring it; nor, finally, 
 could any dead tissue be eliminated from the tissues and 
 excreted from the body. An increase of salt in the food 
 increases the streaming of nutritive fluids in and out 
 of the cells, and the rapidity of metamorphosis of albu- 
 minous substances, so that the nutrition is everywhere 
 quickened. But if this increase be excessive, the destruc- 
 tion of tissues will be also excessive, too much albumen 
 will be thrown out of the tissues, and diarrhoea will be 
 set up in the effort to eliminate the effete matter, just as 
 in starvation. In the " Journal for Diseases of Children " 
 (1873) is related a case where the mother's milk con- 
 tained 8 per cent, of salt, instead of .09 in a hundred 
 parts (the normal amount), and the baby nearly died 
 of inanition and its attendant diarrhoea. He was only 
 saved by the substitution of a wet-nurse. 
 
 This influence upon diffusion is exercised by all the 
 other mineral salts ; but each of these has other uses as 
 well. After chloride of sodium, the alkaline and earthy 
 phosphates are the most important. The first consist 
 of a combination of phosphoric acid with soda and 
 potassa; in the latter, the same acid is combined with 
 magnesia and lime. The phosphate of soda is a con- 
 
28 INFANT DIET. 
 
 stant ingredient of the serum, or liquid mass of the 
 blood ; the phosphate of potassa is as constantly found 
 in the red blood corpuscles, the little bodies that float 
 in the serum and give it its characteristic color and 
 vitality. The phosphate of potassa is also indispensa- 
 ble to the tissue of the muscles. When it is deficient, 
 therefore, new red corpuscles cannot be built up, and 
 the muscular tissue is imperfectly renewed, the blood is 
 impoverished, and the muscles weak. They become soft 
 and flabby, and the weakness of the muscles of the 
 intestines is, in the child as in the adult, a frequent 
 cause of constipation. The phosphate of soda in the 
 serum of the blood affects muscular activity as decidedly, 
 but in another way. When muscles are contracting, 
 various substances contained in their juices are oxidized, 
 or burned, and heat is evolved, as in every process of 
 oxidation. This heat is converted into the force that 
 moves the muscles, and without it the muscles could 
 not contract at all. But by oxidation acids are formed 
 in the substance of the muscles, that gradually accumu- 
 late and take the place of the more combustible sub- 
 stances, just as cinders accumulate in a grate as the coal 
 is consumed. There is the same result in both cases — 
 further oxidation becomes impossible — the production 
 of heat is arrested, and the activity of the muscle stops 
 as inevitably as does the work of a piston from which 
 the supply of steam has been cut off. Moreover, the 
 
INFANT DIET. 29 
 
 acids partially coagulate an albuminous substance in the 
 muscles, so that these become stiff and painful. Hence 
 the feeling of fatigue that follows muscular exertion, 
 and which can only be relieved by washing away the 
 acids and coagulated albumen with a stream of fresh 
 blood. It is the phosphate of soda contained in the 
 blood that neutralizes the acid and dissolves the coag- 
 ulum, and thus restores the muscles to their freshness 
 and vigor, and enables more heat to be generated. De- 
 ficiency of phosphate of soda, therefore, interferes with 
 the action of the muscles, and thereby checks their 
 development. 
 
 Again, the presence of this phosphate of soda in the 
 serum is of importance to the processes of respiration, 
 for it facilitates the absorption of carbonic acid from the 
 tissues, and also the yielding up of this acid again from 
 the blood which traverses the lungs. Finally, or rather 
 at first, before entering the blood or reaching the mus- 
 cles, the phosphate begins its rdle by favoring certain 
 important details of digestion. 
 
 When the food passes out of the stomach into the 
 intestine, it there meets with various fluids, by which, 
 in different ways, it is modified. One of these fluids is 
 secreted by a great gland called the pancreas, which lies 
 behind the stomach, and, in edible animals, is known in 
 the market as " the sweetbread." The pancreatic juice, 
 as it is called, decomposes the fats of the food, and 
 
30 INFANT DIET. 
 
 gylcerine, which is always contained in these fats, is 
 set free. This glycerine should combine with the 
 phosphoric acid derived from the phosphates that have 
 also been present in the food, and form a peculiar 
 product called glycero-phosphoric acid. This is ab- 
 sorbed, and aids the formation of cells in two different 
 ways. In the first place it enters into the composition 
 of a third substance called lecithine, which is essential 
 to cell-formation in any tissue. In the second place, it 
 passes into the cells of the cartilages, there meets with 
 carbonate of lime, and with it forms phosphate of lime, 
 by the aid of which the cartilage is gradually converted 
 into bone. 
 
 ISTow all the steps of this process — decomposition of 
 fats by the pancreatic juice, formation of glycero-phos- 
 phoric acid, of lecithine, and of phosphate of lime — may 
 be arrested if the contents of the intestine are acid 
 instead of alkaline, for the pancreatic juice only acts in 
 presence of alkaline fluids. The phosphate of soda is 
 one of the jtrincipal agents to maintain the alkalinity of 
 the intestinal contents, and to neutralize the various 
 acids which are liable to form during the process of 
 digestion, and which become excessive as one of the first 
 results of disturbance in digestion. Insufficiency of this 
 salt, therefore, will first favor " acidity of the bowels," 
 and ultimately interfere with the formation of tissues, 
 and especially with the growth of bone. The earthy 
 
INFANT DIET. 31 
 
 phosphates, especially the phosphate of lime, have a still 
 closer relation to the growth of bone. The phosphate 
 of lime is one of the most abundant salts of human 
 milk, which contains in 100 parts about 0.25, or a 
 quarter of 1 per cent. " No cell-formation takes place 
 without phosphate of lime," says Beneke. And phos- 
 phate of lime is especially needed to build up the bones, 
 and to give them the solidity by which they are dis- 
 tinguished from all the other parts of the bod}'. We 
 have just shown that the bony phosphates are partly 
 formed in the cartilages at the expense of other combi- 
 nations of lime on the one side, and of phosphoric acid 
 on the other. But they are partly also derived directly 
 from phosphate of lime that is taken in the food and 
 brought to the growing bones by the blood, to combine 
 with organic substances and build up bone tissue. 
 
 The relations of the phosphates to different processes 
 of nutrition are thus seen to be extremely numerous and 
 important. "When they are deficient, the nutrition must 
 suffer seriously, and more in young and growing animals 
 than in others — more, therefore, in the baby than in the 
 adult. The baby is exposed to one disease' peculiar to 
 infancy, and which, though not exclusively due to errors 
 in diet, is still frequently traceable to them. This dis- 
 ease is rickets, once known as the " English disease," and 
 supposed to prevail principally among the children of 
 the wealthy, luxurious, and dissipated classes. It is now 
 
32 
 
 INFANT DIET. 
 
 known to be much more common among the poor. It is 
 a disease affecting the nutrition of the entire body, be- 
 cause it implies a deficiency of phosphates, and conse- 
 quently imperfect development of all the tissues to whose 
 growth the phosphates have been shown to be so impor- 
 tant. There are too few blood corpuscles, the muscles do 
 not grow and cannot work, the bones remain soft and 
 only half organized. The child is therefore anemic, from 
 impoverishment of the blood, its flesh is white and flab- 
 by, the muscles soft and nerveless, the bowels consti- 
 pated, the power of walking retarded. The most striking 
 visible results of the rickety perversions of nutrition are 
 seen in the bones, and as consequences of the abnormal 
 flexibility caused by the deficiency of lime. The head is 
 large and unwieldly, and spreads out of shape, the brain 
 is exposed unduly to external pressure on the softened 
 skull, and convulsions and "crowing croup" may be 
 caused by such irritation. The chest is flattened on each 
 side by the pressure of air upon the softened ribs ; the 
 breast bone is pushed forward, forming the so-called 
 "pigeon breast," and the lungs are so. crowded for room 
 that respiration is seriously impeded. This impediment 
 to respiration, again, interferes with the oxygenation of 
 the blood, and thus renders it less nutritious. It also 
 greatly enhances the danger of every attack of bronchitis 
 or congestion of the lungs to which the child may be 
 liable, besides rendering these more frequent. The 
 
INFANT DIET. 33 
 
 legs bend under the weight of the body, and become 
 " bowed," the thighs being too short in proportion to the 
 forelegs. From this curvature, the baby is able to put 
 his toes into his mouth, a feat that greatly delights the 
 nurse and mother, but should rather awaken their soli- 
 citude. Finally, the pelvis remains too narrow, a mat- 
 ter of small moment with boys, but which in girls 
 entails the prospect of serious dangers in future years, 
 when they in their turn shall be called upon to be mo- 
 thers, and to encounter all the pains and perils of child- 
 birth. Rickets, with all its formidable consequences, has 
 been, in modern times, often ascribed to artificial feed- 
 ing. But this supposition, like the old theory that re- 
 garded rickets in children as a special punishment of 
 vicious luxury in parents, seems to have been made very 
 much under the influence of moral considerations. Closer 
 observation has shown that rickets is much more preva- 
 lent among the poor, who habitually bring up the chil- 
 dren at the mother's breast, than among the rich, where 
 the frequent failure of mother's milk, and dislike of a 
 wet-nurse, often necessitate artificial food. With a. bet- 
 ter understanding of the immediate causes of rickets, it 
 is easy to see that the same conditions which, induce the 
 disease when the child is brought up on the bottle, may 
 exist when it is most strictly limited to the mother's 
 milk. These causes are : 1st. Deficiency of phosphates 
 in the food to supply the place of those consumed in the 
 
3i INFANT DIET. 
 
 organism. 2d. Excessive formation of acids in the diges- 
 tive tube, which, being absorbed into the blood, dissolve 
 out the phosphates already fixed in the body, especially 
 in the bones, and carry them off in the urine. Now, fari- 
 naceous food is very deficient in phosphates, and hence, 
 when substituted altogether or in part for milk in a 
 baby's diet, is indeed often a cause of rickets. But the 
 milk of anemic or of ill-fed women is also deficient in 
 phosphates, and very often in all the solids proper to 
 health}' milk. It may induce rickets therefore quite as 
 surely as artificial food. It not unfrequently happens 
 when two children have been born near together, that 
 the first will be healthy, but the second delicate, with 
 imperfect digestion, or with some marked disorder of 
 nutrition, as manifested in the so-called scrofulous dis- 
 eases, or in rickets. The mother's blood has been ren- 
 dered anemic during her first pregnancy, that is, it has 
 lost a certain amount of its albumen and of its red cor- 
 puscles, because the materials usually employed in their 
 renewal have been diverted to the nourishment of the 
 child. If she become pregnant again before she has 
 recovered from this anemia, her blood is not in a condi- 
 tion to furnish materials for the secretion of normal milk. 
 This is therefore watery, or poor in phosphates, or even 
 deficient in all the solid ingredients, as in the milk of 
 women rendered anemic by other causes, and the child 
 fed upon it will become rickety. 
 
INFANT DIET. 35 
 
 The substitution of cow's milk for breast milk could 
 never be injurious by deficiency of phosphates, for it 
 contains more than double the amount proper to human 
 milk. But cow's milk, as will be shown in another place, 
 is often difficult of digestion on account of the excess of 
 butter, and of the abundance and the peculiar nature of 
 its caseine. The butter and cheese, imperfectly digeste'd, 
 ferment and give rise to acids, which pass into the 
 blood and dissolve out the phosphates, in the manner 
 already described. The action of cow's milk, therefore, 
 when it is injurious, belongs to the second class of causes 
 capable of producing rickets. There are many other 
 things that have the same effect, upon the digestion, and 
 hence are indirectly capable of inducing this disease. 
 The farinaceous food, that is already rendered unsuitable 
 by its poverty of phosphates, is particularly liable to acid 
 fermentation, for its starch is first changed into dextrine, 
 then sugar, finally lactic acid. Meat, prematurely intro- 
 duced into the diet of young children, will remain undi- 
 gested, and give rise to the same acids as form with a 
 surplus of caseine from undigested Cow's milk. So the 
 means so frequently taken to make weakly children 
 strong, often results in making strong children pine away. 
 Absence of fresh air is, among the poor, so generally 
 associated with other conditions known to produce rickets, 
 that it is difficult to fix precisely its degree of influence. 
 But it has been ascertained by careful comparison be 
 
36 INFANT DIET. 
 
 tween different localities, where children brought up 
 on the same food are exposed to fresh and pure or to 
 close and ill-ventilated air, that the latter will alone he 
 sufficient to derange the digestion, induce acid fermenta- 
 tion, solution of bony phosphates, and rickets. The in- 
 fluence is more indirect than that of indigestible food. 
 Respiration of badly oxygenized or impure air alters 
 the composition of the blood : the red blood corpuscles 
 carry less oxygen, and the impoverished blood stimu- 
 lates the nervous system insufficiently. There is less 
 nerve force sent to the stomach, and .hence the gastric 
 juice is not formed in sufficient quantity to digest the 
 food ; and again the undigested part ferments, acids 
 are formed and absorbed with the usual consequences. 
 Finally, as the mother's milk may be injurious by a defi- 
 ciency of phosphates, so it may also act like this second 
 class of causes by the presence of acid. Milk should be 
 feebly alkaline ; and it is pretty well known that hot 
 weather hurts cow's milk that has been standing, by favor- 
 ing the change of sugar into lactic acid, which, when in 
 great excess, curdles the milk. In rheumatic women, 
 whose blood contains this acid, the milk is liable also to 
 be acidified. From this cause the baby will pine, to 
 the great astonishment of the mother who boasts of the 
 abundance of her milk. 
 
 The mechanism of these various digestive arrange- 
 ments will be explained in a little more detail in another 
 
INFANT DIET. 37 
 
 place. They are mentioned here to show the futility of 
 the idea that maternal milk is a necessary preservative 
 against this disease, and that artificial food is the only 
 cause of its occurrence. We see, on the contrary, that it 
 is possible for natural food to become as abnormal as 
 artificial food, and to induce precisely the same disturb- 
 ance in the processes of digestion and nutrition. And 
 when artificial food disagrees with the baby, it does so, 
 in the great majority of cases, on account of definite 
 chemical or physical alterations, that can be easily as- 
 certained and remedied. There are, indeed, other and 
 more subtle properties, that may render unfit for use 
 milk which to all tests but that of the baby's stomach 
 seems perfectly normal ; or, on the other hand, may im- 
 part unexpected nutritive value to milk that does not 
 to our tests differ sensibly from that which has been 
 rejected. These purely animal properties depend upon 
 the constitution of the woman furnishing the milk, and 
 the alterations or diseases of her constitution may be 
 defined, even when the alteration in the rnilk cannot 
 be. We have already spoken of the milk of lymph- 
 atic women, or of those laboring under constitutional 
 diseases, as consumption, epilepsy, skin affections, etc. 
 We have shown, however, that even in these eases a 
 definite chemical alteration of the milk generally exists, 
 sufficient to explain the injurious effect observed upon 
 the nursling. So that the cases are largely in the minor- 
 
38 INFANT DIET. 
 
 ity where we must ascribe this effect to a " vital agency," 
 otherwise inexplicable. But if we do not explain the 
 ill effects of poor milk by a " perversion of its vitality," 
 we have no right to explain the nutritive effects of good 
 milk by the existence of such vitality. Or, in other 
 words, we have no right to say that the milk of the 
 mother nourishes the child in virtue of any mysterious 
 inimitable life-giving power, but on account of a defi- 
 nite chemical composition, that may, with sufficient care, 
 be accurately imitated. 
 
 Before attempting to describe the manner in which 
 the baby's natural food may be most successfully imi- 
 tated, it may be well to say a few words in regard to the 
 manner in which breast milk may be kept in a normal 
 condition, or a healthy composition be restored when 
 this has once been lost. We may then, further, enter 
 upon some details in regard to the processes of infant 
 digestion. When these are already understood and kept 
 in mind, it is much easier to appreciate the modifications 
 that may be induced in them by the different modifica- 
 tions in diet. Whether we consider breast milk, cow's 
 milk, or prepared food, the problem is essentially the 
 same. If the milk is to be obtained from the blood of 
 the mother, we must take care that the right materials 
 in sufficient quantity get into her blood, just as we must 
 put the right materials together into a retort if we wish 
 to get out of the retort a product of definite chemical 
 
INFANT DIET. 39 
 
 composition. This proposition is elementary in its sim- 
 plicity, yet it is constantly forgotten, or obscured by the 
 most fantastic theories. The diet of a nursing mother^ 
 as the regime of a pregnant women, offers a field over 
 which popular prejudices may ride headlong. Many 
 rules are adopted in obedience to some superficial anal- 
 ogy, that a better understanding of the subject would 
 show to be superfluous or absurd. Thus nursing women 
 are often forbidden to eat acids, or acid fruits, lest the 
 milk should turn sour. This theory of resemblances 
 is a "survival" from an entire system of philosophy 
 once very prevalent, according to which turmeric-root 
 was said to cure jaundice because it was yellow, the red 
 sanguinaria was called blood-root, and supposed to make 
 blood, and so on. The truth is that vegetable acids, as 
 soon as they are taken up into the blood, are convert- 
 ed into carbonic acid, which combines with soda and 
 potassa to form alkaline carbonates. Long before they 
 could reach the milk glands, therefore, their acidity is 
 destroyed. Further, when fruits are carefully excluded 
 from the diet, the bowels are very apt to become consti- 
 pated : their contents, retained too long, ferment, and give 
 rise to many so-called fatty acids, which do pass into the 
 blood, and out of it again in the breath, the secretions of 
 the skin, the milk. By them the breath may be ren- 
 dered foul, the skin greasy, and the milk really sour, and 
 become a cause of colic and indigestion to the baby. 
 
40 INFANT DIET. 
 
 Every kind of diet that is known to cause constipation 
 must therefore be scrupulously avoided by a nursing 
 woman, while fruits, on the other hand, are extremely 
 desirable as articles of food for her. In hot weather, 
 when perspiration is abundant, it has been said that 
 the proportion of water in the milk diminishes, and the 
 milk becomes indigestible because too concentrated. It 
 is then necessary to take cooling drinks, abundance of 
 water, to replace that evaporating from the skin, vegeta- 
 ble acids, or citrate of potassa, or even mineral acids, 
 diluted into lemonade. Citric acid (found in lemon- 
 juice) is changed into carbonic acid by taking up oxy- 
 gen from the blood. Less oxygen is left therefore to 
 oxidize or burn the tissues, and less heat is produced. 
 Mineral acids, as the aromatic sulphuric, act in a differ- 
 ent way. They are astringent, contract the blood-vessels 
 of the skin, and thus diminish the amount of blood cir- 
 culating on the surface, and the amount of water that 
 can be transuded through the walls of the vessels, in 
 perspiration. They diminish heat, by antagonizing the 
 combustions going on in the blood, although they are 
 not oxidized, but form salts with alkalies, and thus pass 
 off in the urine. 
 
 It has been said that rheumatic women, whose per- 
 spiration is acid, probably contain lactic acid in the 
 blood, that is, often sufficient to acidify the milk and 
 even become a cause of rickets. It is very customary 
 
INFANT DIET. 41 
 
 to give large doses of alkalies in the treatment of rheu- 
 matism ; and the use of alkaline "waters, as Vichy, is 
 certainly indicated for rheumatic patients who desire to 
 nurse. Where, however, rheumatic tendencies are strong 
 or inveterate in the mother, it is better that the child 
 have a wet-nurse. All anemic women, and all women 
 in whom two or more pregnancies have succeeded each 
 other very rapidly, should take small doses of phos- 
 phates, especially the phosphate of lime, combined with 
 phosphate of iron and with carbonate of lime. In many 
 cases it is useful to begin such treatment, or rather such 
 necessary food, during the pregnancy, and continue it 
 throughout the period of lactation. 
 
 An idea has obtained popularity in some quarters 
 that pregnant women should avoid the use of mineral 
 salts, and especially of lime, in order to " keep the bones 
 of the child soft, and secure an easier labor." As the 
 bones of a newborn child are always " soft," i. e. very 
 imperfectly ossified, this precaution is superfluous, and 
 indeed highly fantastic. The rigid exclusion of salts 
 from the diet of a pregnant woman would seriously 
 interfere with the general nutrition of her body, and of 
 that of the child, but the condition of the bones would 
 be, relatively, little modified. The dangers to the mo- 
 ther from the excessive size of the child, are to be 
 averted by maintaining a due proportion between the 
 whole amount of food and the amount of exercise taken. 
 
42 INFANT DIET. 
 
 An idle and too sedentary life, in which neither the mus- 
 cles nor the nerves of the mother make any demand upon 
 the nutrition, while the consumption of nutritive mate- 
 rial is increased, permits this to be too largely diverted 
 to the child, whose growth then resembles that of a para- 
 site, and is out of all pi-oportion to the body of the 
 mother, to which it should be adjusted. 
 
 Deficiency of butter or of caseine in the mother's milk 
 is to be remedied, when possible, by nourishing diet to 
 the mother. It is important to remember that the 
 same food may be nourishing or not, according to the 
 capacity for digestion, and that, whenever it is con- 
 sidered desirable to introduce more food into the body, 
 it is necessary to provide at the same time for increas- 
 ing the digestive capacity. This is why we must insist 
 upon exercise, which is often recommended in general 
 terms to nursing women, without any reason being 
 given for the precept. Muscular exercise increases the 
 respiration, or the rapidity with which substances are 
 oxidized in the blood and eliminated from it by the 
 lungs and kidneys. Hence is increased the rapidity of 
 the demand for new material to be thrown into the 
 blood ; and the sensation of hunger, which interprets 
 this demand, is more intense, and more often renewed, 
 the appetite is awakened, and the stomach will bear 
 more food. Other effects of muscular exercise are im- 
 portant, but for our purpose this is the principal — that 
 
INFANT DIET. 43 
 
 it accelerates the processes of nutrition and denutrition, 
 and hence makes room for more material to be taken up 
 into the system, and utilized not only in the formation 
 of solid tissues, but of such liquid tissues as the milk. 
 
 The same result is obtained by agencies which quicken 
 the circulation in the skin and muscles, and. increasing 
 their nutrition, increase the demand for the materials 
 of nutrition. The supply that will be thrown into the 
 blood will be sufficiently in excess of the demand to 
 provide for an increase also in the secretion of milk, 
 even in persons in whom the nutritive demand created 
 by this secretion seems insufficient to increase the appe- 
 tite. Cold bathing, and systematic rubbing and knead- 
 ing of the limbs and surface of the body, are powerful 
 means of securing this end. 
 
 The degree of excess in the quantity of food required 
 by a nursing woman is very variable ; as a rule, however, 
 such excess is much more generally required than during 
 pregnancy. Here a spontaneous provision exists for the 
 surplus material required for the development of the 
 child, in the mechanical difficulties that render muscular 
 exercise difficult, and thus diminish the demand for food 
 on the part of the mother. If, therefore, she continue her 
 ordinary scale of diet, she will, other things being equal, 
 still have enough both for herself and the child. But 
 during lactation, her capacity for physical activity returns, 
 or should return, and she is then compelled to sustain an 
 
44 INFANT DIET. 
 
 extra function of nutrition, while all the ordinary de- 
 mands for nutrition continue in full force. "We think 
 it is because the necessity for extra diet is insufficiently 
 appreciated, and met by inadequate provision, or by over- 
 feeding without means to increase the digestive power, 
 that the nutrition of so many women becomes more seri- 
 ously impaired by nursing than by pregnancy, and that 
 their supply of milk is so soon exhausted. 
 
 As these remarks on the diet of nursing are merely in- 
 cidental to our subject, and not intended to be exhaustive, 
 we will omit a detailed consideration of the articles of food 
 that are the most nourishing, that is, that will best tend 
 to secure in the milk a normal proportion of caseine and 
 butter. Only one or two points of special interest may 
 be touched upon. Similar to the popular prejudice that 
 would exclude fruits from the diet of a mother, is that 
 which insists on a preponderance of meat. Like all popu- 
 lar ideas, this is the ghost of a theory that was once held 
 as scientific, when albuminous substances were considered 
 to be the principal articles of diet — those preeminently 
 required to repair the wear and tear of the body ; and 
 that to these the hydrocarbons, the sugars, starches, and 
 fats, were merely accessor}', and to be burned as fuel to 
 maintain the heat of the body. It was found, however, 
 by experiment, that pure albumen was entirely insufficient 
 to sustain life, and that dogs fed on it died of inanition. 
 Then it was found that the combustion of albuminous 
 
INFANT DIET. 45 
 
 substances contributed to the heat of the body, though 
 in a less degree than that of the hydrocarbons. Quite 
 recently, the production of heat has assumed a new im- 
 portance, from the discovery of its relations to motor 
 force. It was found that every movement which took 
 place in the living body required a certain amount of 
 heat — that the contraction of a muscle was as dependent 
 on heat as was the movement of a piston in a steam- 
 engine. This astonishing discovery has quite changed 
 the aspect of the functions of different kinds of food, 
 and given to the hydrocarbons a value in some respects 
 higher than that of albuminous substances, though these 
 are represented by meat, which most resembles the tis- 
 sues of the human body. These, therefore, replace those 
 tissues when they are destroyed, as iron and brass repair 
 the waste in the material of which a locomotive is made. 
 But as the locomotive requires coal in order to be set in 
 motion, and as the need for the consumption of coal 
 during its period of activity is much greater than the 
 need of repair, so the human body, at any moment, re- 
 quires a much larger proportion of food that shall furnish 
 heat, than it does of food which may be directly assimi- 
 lated to its tissues.* 
 
 The only circumstances calling for a very large pro- 
 portion of nitrogenous food, i. e. meat, are those that 
 
 * Comparison quoted by Schiff from the memoir of Fisk and 
 Wislicenus. 
 
46 INFANT DIET. 
 
 involve great activity of the nervous system. All others, 
 and perhaps especially the nutrition of nursing women, 
 require a large proportion of other food, and no advantage 
 is gained by insisting on a meat diet as more nourish- 
 ing. The normal proportion between nitrogenous and 
 non-nitrogenous food is about as one to four, and this 
 proportion need not be varied for nurses. The excess 
 of food required is better made with oatmeal, Indian- 
 meal gruel, bread, chocolate, etc., than with an extra 
 allowance of meat. 
 
 There is no indication for stimulants in order to in- 
 crease the quantity or the richness of the milk, although 
 they may sometimes be needed to support the nursing 
 mother. We have already described those cases where 
 intense pain is produced in the chest by the act of nurs- 
 ing, and where, in the absence of any soreness about the 
 nipples or inflammation of the breast, the pain must be 
 attributed to neuralgia of weakened nerves, when these 
 are excited to enable the gland to secrete milk. Such 
 pain may often be averted by a glass of wine or ale, taken 
 just before giving the child the breast. Alcobolic stimu- 
 lants are needed wherever the woman has become de- 
 bilitated by nursing, and where the secretion of milk 
 threatens to be suspended from this cause, they may in- 
 directly increase it. But not otherwise. 
 
 In regard to a deficiency of sugar, or to an excess of 
 salts in the milk, no remedial measures of diet can at 
 
INFANT DIET. 47 
 
 present be prescribed. Remedies are usually addressed 
 rather to other conditions of the milk which may accom- 
 pany these, as to the excess of caseine found with deficien- 
 cy of sugar, or to the excess of water, with excess of salts, 
 especially the chloride of sodium. It has been already 
 said that sugar may be added to the milk which nour- 
 ishes a child at the breast, as easily as to that which he 
 would take from the bottle, by the simple expedient of 
 giving it to the child in water immediately before the 
 breast. In the same manner the excess of caseine is 
 remedied. 
 
 Instead of the sugar-water mentioned, above, we may 
 give the bab} T each time before it is put to the breast a 
 table-spoonful or more, according to age, of strained and 
 well-sweetened oatmeal gruel, for reasons, and prepared 
 in a manner to be designated hereafter. Thus sugar is 
 added, the milk is diluted in the stomach by the decoc- 
 tion of oatmeal, the caseine is brought into a slow con- 
 tact only with the gastric juice, and is better prepared 
 for being dissolved again for digestion, and less apt to 
 stimulate the gastric glands into undue action. For thie 
 plan, also, which has been serviceable in many cases where 
 the former simple one would not suffice, I claim good 
 theoretical reasons, and the results of a various, and, I 
 believe, unbiassed observation of a long number of years. 
 
 It would certainly often be desirable, were it possible, 
 to modify the mother's milk in other ways than those 
 
48 INFANT DIET. 
 
 above specified, and especially to impress upon it those 
 subtle animal characters to which we have referred as 
 eluding chemical analysis, yet becoming the means of 
 confirming constitutional peculiarities, or of transmit- 
 ting constitutional diseases. But for this purpose, the 
 physical education of the mother must precede by many 
 years the moment in which she assumes the function of 
 lactation, and must, to facilitate the accomplishment of 
 this function, secure adequate development for all other 
 bodily functions. In this generality the subject escapes 
 our present grasp. We turn to another — from the mo- 
 ther to the baby — from the consideration of his prim- 
 itive natural food, to that of the methods by which 
 he is enabled to appropriate it to his use. It is only 
 when the process of infantile digestion is clearly under- 
 stood, that reasoning about infants' food becomes intel- 
 ligible. 
 
 It is understood that food, in its passage through the 
 alimentary canal, undergoes a series of chemical changes, 
 by which it is rendered fit for absorption into the blood 
 and assimilation by the tissues. These changes are ef- 
 fected by the fluids secreted at different parts of the 
 canal, and which act differently upon the various ele- 
 ments of which the food is composed. The first diges- 
 tive fluid is the saliva, which is poured put by three 
 pairs of glands that surround the cavity of the mouth, 
 and becomes intimately mixed with the food at the first 
 
INFANT DIET. 49 
 
 moment of its ingestion. The influence of the saliva is, 
 however, limited to one substance, starch, which is con- 
 verted by it into sugar, and thus rendered soluble. It 
 is remarkable that this change, the first which takes 
 place in the food of human beings, is likewise the first 
 step in the digestion of plants. During the winter, an 
 immense amount of starch remains stored up in the roots 
 — sometimes, as in the potato, constituting the entire 
 edible part of the plant. Concealed with the starch is a 
 minute quantity of a peculiar albuminous substance 
 called a ferment, which in the spring begins to act upon 
 the insoluble starch and convert it into soluble sugar, 
 that may rise in the sap and be carried to all parts of 
 the stern to feed the growing buds. A similar ferment 
 exists in human saliva, and though in very minute quan- 
 tity (for ninety-nine parts out of one hundred of saliva 
 are water), suffices to convert the starch of farinaceous 
 food into sugar, which passes into animal blood-vessels, 
 and is carried to remote cells where starch could never 
 penetrate. 
 
 Now, in relation to infant diet, the most interesting- 
 point about starch is the fact that the typical food, 
 milk, does not contain any. This fact is already a 
 warning that farinaceous food is probably unsuited to 
 young babies, for such food principally consists of 
 starch, and is therefore as foreign to nature as we could 
 well make it. It is, indeed, the only elementary food 
 
50 INFANT DIET. 
 
 that is not represented in milk. Instead of starch, that 
 must become grape sugar before it can be absorbed, we 
 find milk sugar already formed ; and, corresponding with 
 this peculiarity, we find that in young babies the appa- 
 ratus for changing starch into sugar, the group of salivary 
 glands, is very incompletely developed. There are, as 
 we have said, three pairs of salivary glands: the parotids, 
 which on each side extend from the ear to the angle of 
 the jaw, and which become inflamed in " mumps ; " the 
 submaxillary, which are under the chin ; finally, the sub- 
 lingual, smallest of all, and which, as the name implies, 
 lie on the floor of the mouth under the tongue. 
 
 These glands begin to develop as early as the second 
 month of fcetal life, and about the end of the third are 
 well marked. But they are small at birth ; the parotid 
 glands which, combined, weigh at fifteen months 80 
 grains, and 120 at two years, weigh but 34 at the age of 
 a month. 
 
 In adult life, moreover, the function of the glands 
 is much influenced by certain nerves, as some branches 
 of the facial nerve,* or the nerve distributed to the 
 tongue. When these nerves are irritated, a considerable 
 flow of thin limpid saliva takes place. But in young 
 babies, irritation of these nerves has very little effect. 
 ISTot only the salivary glands are imperfectly developed, 
 but the parts of the brain to which these nerves run 
 are unaccustomed to respond to irritation. 
 * Chorda tympani. 
 
INFANT DIET. 51 
 
 Besides the salivary glands of the month, there is a 
 large gland in the abdomen whose secretion has the 
 power of turning starch into sugar. "We have already 
 mentioned it as the pancreas, and described its situation 
 behind the stomach, and alluded to its popular name, in 
 edible animals, as the " sweetbread." We have referred 
 also to one important action of the pancreatic juice — 
 that it emulsifies fats and prepares them for absorption ; 
 and decomposing fats into the fatty acids and the gly- 
 cerine of which they are composed, enables the latter to 
 combine with phosphoric acid, and be carried to the 
 bones to form the solid phosphate of lime. In order to 
 compare the action of the pancreas upon starch with 
 that of the parotid, Dr. Korowin, of St. Petersburg, 
 has made some interesting experiments. (Central Blatt, 
 1873.) 
 
 He made infusions of the pancreatic glands and of 
 the parotids, by steeping them in water so as to extract 
 their juices, and then adding these to solutions of starch. 
 It was thought possible that, although the salivary glands 
 of the mouth were incapable of digesting starch readily 
 during the first months of the infant's life, the pancreas, 
 which has" been called " the salivary gland of the abdo- 
 men," might be able to supply their deficiency. But 
 the experiments showed, on the contrary, that the pan- 
 creas acquired its starch-making power even later than 
 the parotid glands. According to Korowin, the infu- 
 
52 INFANT DIET. 
 
 sions of the pancreas taken from infancy in the first 
 month of life, exhibit no power to change starch into 
 sugar. The first traces of this fermentative effect be- 
 come perceptible in the course of the second month only, 
 but it increases so rapidly in the third month as to per- 
 mit of a quantitative analysis of the new-formed sugar 
 being made. It then increases gradually until the end 
 of the first year, when it is developed to its full extent. 
 
 Infusions of the parotid gland, however, have the 
 effect of transforming boiled starch into sugar in the 
 very first days of life. The quantity of newly-formed 
 sugar is so great as to be measurable. The fermenta- 
 tive effect of the parotid gland corresponds with the 
 size of the child. 
 
 Korowin has besides experimented upon the saliva 
 of infants. To obtain it, he introduced pieces of fine 
 sponge into the infants' mouths. After they had sucked 
 awhile, he withdrew the sponge. Some saliva was thus 
 collected within a few minutes after birth ; but great 
 patience and pertinacity were required in gathering it 
 for the period of two or four weeks. Tenfold the time 
 was required at this age as in infants of three months. 
 A single cubic centimer required from fifteen to thirty 
 minutes. In some cases none whatever was obtained, 
 although there had been some secretion before. The 
 amount of saliva increased considerably about the end of 
 the first month ; in the fourth month a cubic centimeter 
 
INFANT DIET. 53 
 
 or more was obtained in from five to seven minutes. 
 This is the period when the increased salivation is per- 
 ceptible to every one. Korowin collected saliva from 
 seventeen infants, at the age of from one to ten days. 
 It transformed starch into sugar. This fermentative ef- 
 fect of saliva increased with age up to the eleventh 
 month. As a number of infants remained under observa- 
 tion during a period of several months, the experimenter 
 had ample opportunities to verify this fact. His obser- 
 vations are numerous, his quantitative analyses alone 
 amounting to one hundred and twenty. Finally, he 
 compared the diastasic (i. e. sugar-making) effect of the 
 saliva of an infant of eleven months with his own, and 
 found equal results from equal quantities. 
 
 Thus, from what we know at the present time about 
 infant saliva, we conclude that a small amount of starchy 
 food can be made available as a nutriment even before 
 an infant is three months old. Additions to milk need 
 not be entirely free of starch ; but as the amount of saliva 
 may differ in individuals, at various times and from 
 various nervous and mechanical influences, it is safer to 
 select from the list of farinaceous or amylaceous articles 
 such as contain albuminous matter and salts in prepon- 
 derance. 
 
 There is probably no rule for infant diet of more im- 
 portance than that which regulates the amount of starch 
 which may be given to the child ; for errors on this point 
 
54 INFANT DIET. 
 
 are extremely frequent, and have most serious conse- 
 quences. It is the general belief of mothers and nurses 
 that thick food is more nutritious than thin, and hence, 
 almost as a matter of course, they mix corn-starch, arrow- 
 root, farina, bread-crumbs, etc., in the milk of the youngest 
 child with whose natural food there is any pretext for 
 interference. Now, it would be nearly as rational to 
 thicken the milk with sand. In reality, other things 
 being equal, the thinner food is, the more nourishing . 
 it is, for the very simple reason that it is more readily 
 absorbed. We will refer to this important fact again, in 
 speaking of digestion in the stomach. And in the second 
 place, as shown by the above-mentioned experiments on 
 the salivary glands, since so small provision exists in the 
 young child for changing starch into sugar, when any 
 abundance of starchy food is given, the larger part re- 
 mains unchanged, insoluble, indigestible, and undigested. 
 Any substance that stays in the stomach or bowels with- 
 out being dissolved, is liable to cause irritation and pain, 
 and many fits of screaming and colic result from nothing 
 else. But the remote effects of this innocent-looking . 
 farina are even more disastrous. A fermentation is set 
 up of a different nature from that determined by the 
 special ferment of the saliva, instead of sugar, lactic acid 
 is formed in excess, passes into the blood, and dissolves 
 out the earthy phosphates from the tissues, in the way 
 that has been already described. Hence an arrest of 
 
INFANT DIET. 55 
 
 nutrition, softened bones, general rickets. It is because 
 children brought up on the bottle are so frequently cram- 
 med with farinaceous food, and become rickety from this 
 cause, that so many writers have ascribed rickets to the 
 mere absence of breast milk. 
 
 On account of the great prevalence of this error in 
 diet, and the insidious manner in which it may induce 
 disease, intelligent mothers should be prepared to detect 
 in their babies early signs of disordered nutrition, so that 
 medical skill may be invoked before it is too late. The 
 most important early signs that may be recognized by 
 the non-medical observer are the following: 
 
 Green passages, with alternations of constipation and 
 diarrhoea. 
 
 Profuse sweating about the head. 
 
 Tendency to hang the head backward. 
 
 Slight swelling of the wrists and ankles. 
 
 Slight curvature of the leg below the knee. 
 
 Dentition retarded beyond the tenth month. 
 
 Yery large fontanelle after the sixth month. 
 
 The green color of the passages is not due to an 
 excess of bile, but to the acid which colors the bile that 
 should be present. The acidity of the passages is easily 
 demonstrated by laying a piece of blue litmus paper on 
 the napkin. It will immediately turn red. 
 
 Sweating of the head is of no importance if only ob- 
 served when the child has been overheated, has been 
 
00 INFANT DIET. 
 
 sleeping in a warm bed, etc. The rachitical sweating 
 will appear even when the child has been kept cool. 
 
 The fontanelle, or opening in the top of the head, 
 gradually increases in absolute size until the sixth month, 
 because the growth of the head is more rapid than the 
 process of ossification by which the fontanelle should be 
 closed. But from the age of six months, it should grow 
 constantly smaller, and by fifteen months should be en- 
 tirely closed. 
 
 The peculiar soft white flesh so characteristic of 
 rachitical (rickety) children is usually a matter of pride 
 with the mother, who boasts of the beautiful complexion 
 of her bab}\ It is perhaps scarcely possible for her to 
 distinguish the fairness that indicates disease, from that 
 which may be legitimately admired ; and hence this sign 
 is not given among those that she may look for to test 
 the health of her child. 
 
 The deformities that result from an advanced degree 
 of rickets, the pigeon breasts and crooked legs, are so 
 well marked that no ordinarily careful mother would- 
 overlook them. She is only likely to attribute them to 
 an accident, a fall, to the carelessness of a servant. The 
 absurdity of this idea is made evident by the details that 
 precede, as also the injustice that attempts to shift the 
 responsibility of misfortune. 
 
 After leaving the mouth, the baby's food descends by 
 the oesophagus to the second reservoir provided for its 
 
INFANT DIET. 57 
 
 reception, the stomach. To the popular view this is 
 altogether the most important part of the alimentary 
 canal, and almost the exclusive organ of digestion. Now, 
 in adult human beings, this view is extremely incorrect, 
 for the effect upon food of the saliva, and of the process 
 of mastication, is already important, before the stomach 
 is reached, and a large proportion of the food leaves the 
 stomach undigested, and is only completely prepared for 
 absorption in the intestine. But in babies, the relative 
 importance of the stomach is much greater. There is no 
 mastication, and, as we have seen, little saliva ; and of the 
 typical food, milk, a much larger proportion than of any 
 other is completely digested in the stomach, leaving a 
 much smaller residue to be transmitted to the intestine. 
 
 The nature of infants' food is so different from that 
 of adults, that the process of digestion is also in many 
 respects necessarily different. The shape and position 
 of the stomach is already different. It is situated of 
 course in the same place, that is, behind that part of the 
 abdominal wall called the epigastrium, and which con- 
 stitutes the triangular space below the breast bone, and 
 between the ribs that diverge on each side from their 
 attachment to this bone. In the adult, the stomach lies 
 transversely ; but in the baby, the liver is so large as to 
 stretch entirety across the epigastrium to the left side, 
 and the stomach is pushed back, so that it lies obliquely 
 from left to right. Again, in the adult, the stomach is 
 3* 
 
58 INFANT DIET. 
 
 much dilated at its left extremity, that into which the 
 oesophagus opens, and into winch the food first falls. 
 From this end, called the cardiac on account of its 
 proximity to the heart, the stomach tapers towards the 
 other end, that is very much smaller, in fact, only just 
 the diameter of the small intestine with which it is con- 
 tinuous, or which may be said to be fitted on to it as a 
 tube may be fitted to the beak of a retort. A cone is 
 thus formed, with the base at the left and the apex at 
 the right, and curved upwards and backwards. On ac- 
 count of this curve, the lower border pf the cone is long 
 and convex, the upper border short and concave. 
 
 The form of the stomach, and its size as compared 
 with that of the other parts of the digestive canal, vary 
 much in different animals. There is a primitive type 
 that seems to represent the simplest and most abstract 
 conception of a digestive apparatus, that is, a straight tube, 
 with a mouth at one extremity and an anus at the other, 
 and receiving here and there the secretions from a few 
 glands, scattered along its course. This is the appearance 
 of the alimentary canal in the embryos of all vertebrated 
 animals, and in some fishes. It becomes more complicated 
 when the organism to be nourished is more complex, and 
 requires more complex food, and more elaborate diges- 
 .tive processes. First, the straight tube grows longer, 
 and must be folded up in order to fit into the body. 
 Then it dilates at certain parts of its course : the pharynx 
 
INFANT DIET. 59 
 
 is first formed, then the stomach, then, the intestine 
 becomes divided into a small and large portion, then 
 certain parts of the latter are specially enlarged, as the 
 caecum and rectum. The glands that open into the tube 
 also grow, and the digestive apparatus and the abdo- 
 men thus acquire an immense size relatively to the 
 rest of the body. This is especially noticeable in herb- 
 ivorous animals, in whom the digestion is the most 
 absorbing function, and continues almost as uninterrupt- 
 edly as breathing or circulation. Among birds and rumi- 
 nating animals, there are several stomachs, each with a 
 distinct office, and the process of regurgitation and remas- 
 tication of food gives to the mouth and its secretions an 
 importance in" digestion that does not exist anywhere else. 
 Among carnivorous animals, the digestive apparatus is 
 more compact. There is only one stomach, that con- 
 centrates in itself the apparatus and the functions that 
 in other animals are distributed among several organs. 
 The action of the saliva is only begun in the mouth, 
 and not completed until after a long sojourn of the 
 food in the stomach. The stomach is divided into two 
 parts, one secreting the gastric juice that shall transform 
 the food ; the other providing for the absorption of ma- 
 terials that fo not require such transformation. This 
 double action is further effected by a double arrange- 
 ment for the circulation. Part of the blood-vessels run 
 vertically, surrounding the glands that are plunged in 
 
60 INFANT DIET. 
 
 the thickness of the mucous membrane ; and another part 
 runs horizontally to the surface of the membrane. The 
 first furnish material from the blood for the secretion of 
 the glands, the second absorb soluble material from the 
 cavity of the stomach into the blood. 
 
 Now, the peculiarities by which the stomach of the 
 human infant differs from that of the adult, either cor- 
 respond to an inferior stage of animal development, or 
 are exaggerations of those by which the stomach of the 
 carnivorous animals differs from that of the herbivorae. 
 We have said that its situation was more oblique — it is, 
 indeed, nearly vertical — and as the large (cardiac) end is 
 very much less developed, the entire organ is narrower 
 than in the adult, and therefore offers a slighter deviation 
 from the straight vertical tube that constitutes the prim- 
 itive type of digestive canal. Its shape, therefore, re- 
 sembles that of the dog. The cardiac half of the stomach 
 is that which contains the gastric glands for the secre- 
 tion of pepsine, and its smaller size in babies implies 
 that in them there is less pepsine secreted for the diges- 
 tion of albuminons substances. 
 
 Nevertheless, as we have said, of the food which is 
 adapted to this imperfect stomach, a much larger pro- 
 portion is digested in it, and that more rapidly, than is 
 the case with adults. With them the stomach is not 
 entirely emptied of food under four or five hours after a 
 meal ; but in babies the digestion is over in little more 
 
INFANT DIET. 61 
 
 than an hour, and within two hours the stomach is ready 
 for more. In this rapidity of action, the baby's stomach 
 resembles that of the carnivorous animals, and is more 
 widely removed from the herbivorous, in whom diges- 
 tion is going on nearly all the time. In some of the 
 herbivorse — as the. rabbit — the stomach is never empty. 
 On the other hand, the frequency with which the repast 
 must be renewed for the infant, obliges him to spend 
 a much larger part of the day in eating, so that he re- 
 sembles the herbivorse in the disposition of his time- — 
 although exaggerating the type of the carnivorae in the 
 action of his stomach. 
 
 The facility with which a baby vomits is another 
 point of resemblance with the latter class of animals, and 
 of difference from the herbivores, who vomit with much 
 greater difficulty, or even not at all. " The stomach of 
 the dog," observes Sehiff, " does not enter into the long 
 discussions with indigestible food to which the human 
 stomach is habituated, but rejects it promptly and com- 
 pletely, and, once relieved, returns to its functions again 
 without delay or malaise." It is the same with babies, 
 in whom vomiting is so frequent that it is often re- 
 garded by mothers and nnrses as a sign of health. Its 
 facility has been explained by the vertical position of the 
 stomach, and the small development of its cardiac ex- 
 tremity, so that the cavity continues in nearly a straight 
 line with the oesophagus. (Schultz.) These circumstances 
 
62 INFAJSTT DIET. 
 
 may show why the contents of the stomach can pass 
 more easily out of the orifice by which they have entered, 
 but they do not explain the impulse that sets them in 
 motion. This is given, in the child as in the adult, by 
 the layers of muscles surrounding the stomach, and 
 which are compressed when the stomach is distended. 
 These muscular layers consist of the abdominal walls in 
 front, and, above and at the side, of the diaphragm, a 
 great horizontal muscle that forms the floor of the chest, 
 and shuts in the lungs from the abdominal cavity. In 
 the adult, the cardiac extremity of the stomach is capa- 
 cious, and sinks back into the abdomen as it becomes 
 filled with food. Only when the accumulation of food is 
 excessive is the anterior wall of the stomach distended, 
 and then the lower border rises and presses against the 
 abdominal walls. From the small size of the cardia in 
 babies, this point of distension is much sooner reached, 
 the long narrow stomach rolls upwards, and, compressing 
 the abdominal muscles, is in-turn compressed by them. 
 At the same time the stomach is pressed by the large 
 liver against the diaphragm, so that the latter has less 
 space into which to descend when the lungs expand 
 during inspiration. If, therefore, the baby takes a longer 
 breath than usual, and the diaphragm is pushed down a 
 little farther, it also compresses the stomach, which thus 
 is squeezed on nearly all sides. (Allix.) At the beginning 
 of digestion, when the stomach is most distended and the 
 
INFANT DIET. 63 
 
 pressure from without the greatest, the pyloric orifice, or 
 the opening into the intestine, is closed. It only opens 
 gradually, and in proportion to the amount of food that 
 has become thoroughly prepared for entrance to the in- 
 testine. Since this proportion is always smaller with 
 babies than with adults fed upon solid food, the pylorus 
 habitually opens with more difficulty, or, rather, it has not 
 yet became habituated to open with ease. The door of 
 entrance to the stomach, on the other hand, or the cardiac 
 orifice, is opened by muscular fibres which from birth 
 are ready to respond to irritation : the whole force of the 
 pressure, therefore, to which the stomach is submitted, 
 bears in the direction of the least resistance, upon this 
 orifice, and the milk is squeezed out of the stomach into 
 the oesophagus, its exit being facilitated, as already said, 
 by the nearly straight line in which this canal continues 
 with its own cavity. 
 
 From this disposition, the baby's stomach, like that 
 of the dog, is able to avoid " long discussions " with food 
 indigestible either from quality or quantity, and to relieve 
 itself promptly, where indecision would be most disas- 
 trous. 
 
 But there are many kinds of vomiting, with varying 
 degrees of importance, as will be shown later when we 
 speak of the details of digestion. 
 
 The fact that the baby's stomach resembles that of car- 
 nivorous animals so much more than that of herbivorse 
 
64 INFANT DIET. 
 
 should already discredit the notion prevalent among 
 some people, that vegetable food is more " natural," 
 hence more "innocent," hence more suited to children 
 than animal food. Really fierce denunciations appear 
 from time to time in popular treatises on hygiene, against 
 the " fatal practice " of making '■' an innocent child a flesh- 
 eater." The moral impulse to this prejudice, that claims 
 to be so enlightened, is a curious instance of "survival" 
 of the old savage idea that persons acquired the charac- 
 teristics of the animals upon which they fed.* Practi- 
 cally, and as a means of preventing the premature intro- 
 duction of solid food into the diet of the young child, 
 the prejudice may be useful ; but the theory upon which 
 it is based is absurd, inasmuch as the milk, unquestionably 
 destined for babes, is a purely animal food, and desirable 
 precisely on account of the facility with which it may 
 be assimilated to animal tissues. 
 
 The peculiarities in this typical food all correspond 
 to peculiarities in the digestive apparatus of young chil- 
 • dren. We have already insisted on the absence of starch, 
 which is necessitated by the imperfect action of the sali- 
 vary glands. The liquid form of the food is as evidently 
 necessitated by the absence of means of mastication. It 
 would be equally correct, however, to say that the teeth 
 are absent because rendered superfluous by the liquid 
 form of the food, and because they would, by injuring 
 
 * See Lubbock, " Origin of Civilization," p. 12. 
 
INFANT DIET. 65 
 
 the nipple, impede the process by which the food is 
 obtained. This special form of food, therefore, must be 
 imposed by more general conditions than those of the 
 mouth. It is common to the young of only one class of 
 vertebrated animals — the mammifers. Birds have no 
 teeth, but from the time they emerge from the egg they 
 are fed upon solid food — even those species •which are 
 at first too feeble to feed themselves. In birds, however, 
 as is well known, the trituration of food is effected in the 
 gizzard, and hence requires no voluntary muscular exer- 
 tion such as that involved in mastication. For this exer- 
 tion the young of mammifers, and especially the human 
 young, are^too feeble, and this is the first reason why they 
 are provided with food that does not require it. Those 
 animals which, like calves and colts, rapidly acquire mus- 
 cular force enough to ran about, begin to browse long 
 before they have given up nursing, and the maternal milk 
 is continued as a luxury long after it has ceased to be the 
 exclusive article of food. But kittens and puppies lie 
 huddled in blind impotence for many days : their mus- 
 cular feebleness approaches that of the human baby, and, 
 like the latter, they remain till a much more advanced age 
 entirely dependent upon milk. The muscular strength 
 seems therefore itself to be proportioned to the deeree to 
 which the animal can digest other substances than those 
 contained in milk. In herbivorous animals destined later 
 to feed upon starchy substances, the greater development 
 
66 INFANT DIET. 
 
 of the pancreas and of the salivary glands, and in rumi- 
 nants the four stomachs, enables starch to be digested 
 much earlier than is possible in animals possessed of a 
 single stomach and little saliva, as kittens, puppies, and 
 human babies — in a word, of animals who in adult life 
 will feed partially or altogether upon flesh. Hence the 
 calf can feed upon grass, that contains starch ; but the kit- 
 ten needs from the beginning a food that shall represent 
 flesh, and requires a concentrated and compact digestive 
 apparatus, and milk is the only food which fulfils these 
 conditions. As in all physiological series, therefore, it is 
 difficult to say which is the starting-point. We can 
 hardly ever affirm that any one condition exists in order 
 that another may exist : we can only say that a number, 
 mutually dependent, coexist. The baby's food is liquid 
 because it has no teeth, and it has no teeth because it is 
 not strong enough to masticate, and its strength increases 
 more slowly than that of all other animals because its 
 scale of development is everywhere larger and the rate 
 slower, and on this account must it be longer dependent 
 upon the mother for food ; and in all other mammifers 
 similarly situated in the above respects, milk is the only 
 liquid food procurable by the mother. The only mother 
 who might exercise a choice in this respect, the human 
 mother, is forbidden to do so because the others cannot, 
 and because the organization of her baby has been sub- 
 mitted to the laws which govern that of their young. 
 
INFANT DIET. 67 
 
 Upon following the milk into the stomach, we shall 
 find other reasons for its liquid form, and for the absence 
 of starch, than those which have been mentioned. Water, 
 contained in all substances, is of course in much larger 
 proportion in liquids than in others. In milk, about 
 eighty-eight parts in every one hundred are water. The 
 water facilitates the digestion of the albuminous sub- 
 stance, the caseine. In experiments upon digestion of 
 albumen with gastric juice obtained from the stomach 
 of animals, it was noticed that after a certain time the 
 process began to slacken, but was renewed merely by the 
 addition of water. The gastric juice became saturated 
 with the substances it had dissolved, and ceased to act 
 upon what remained until it had been diluted. In the 
 living stomach this dilution is of even greater import- 
 ance, for it permits of the immediate absorption of the 
 substances soluble in water, and which do not require the 
 specific action of the gastric juice.. The elements of the 
 milk thus rapidly taken up into the blood with its water 
 are the sugar and salts : the butter passes into the intes- 
 tine, and the caseine alone is submitted to the action of 
 the gastric juice. 
 
 The gastric juice is made up of three things, water, 
 hydrochloric acid, and an albuminous substance called 
 pepsine. This pepsine, when associated with acid (but 
 not otherwise), attacks albuminous substances in such a 
 way that they' become disintegrated, and finally trans- 
 
68 INFANT DIET. 
 
 formed into a soluble substance called peptone, and an 
 insoluble residue called parapeptone. 
 
 The pepsine is formed in glands situated in the car- 
 diac half of the stomach (relatively small in babies). 
 These glands are straight tubes, standing side by side in 
 the thickness of the mucous membrane, with an open 
 extremity turned towards its surface, and a closed end 
 plunged in its depth. Each tube is filled with large 
 irregularly shaped cells, and these secrete the pepsine. 
 The material for the secretion is furnished by a net- 
 work of blood-vessels, which, as has been said, enlace 
 each peptic tube. The amount of pepsine that may be 
 formed depends very much upon the substance circu- 
 lating in the blood of these blood-vessels. Ey injecting 
 into the veins of an animal solutions of certain sub- 
 stances, as sugar, digested meat, or especially dextrine, 
 a substance intermediate between starch and sugar, it is 
 possible to greatly increase the amount of pepsine con- 
 tained in the stomach glands. The same thing will hap- 
 pen when the injection is made into the rectum, whence it 
 is absorbed into the blood. Finally, in ordinary circum- 
 stances, the material for the formation of pepsine is derived 
 from the substances soluble in water which are absorbed 
 from the stomach at the besrinninor of- the digestive 
 process, pass into the blood, and set the glands to 
 work. This fact justifies the habit of eating soup before 
 meat. The soluble materials of the soup pass into the 
 
INFANT DIET. 69 
 
 blood, and the blood-vessels surrounding the glands, and 
 start their secretion, so that by the time the meat arrives 
 there is a sufficient proportion of pepsine ready to digest 
 it. In older children and in adults the water of the saliva 
 prepares a solution of many substances which are not 
 acted on by the peculiar ferment of this secretion. The 
 absence of saliva in babies is therefore another condition 
 that necessitates a large amount of water in their food. 
 So long as the food remains in the stomach, whatever 
 is digested and absorbed contributes to the secretion 
 of new quantities of pepsine, so that more is manu- 
 factured as fast as needed. But when the transforma- 
 tion of the food has reached a certain stage, the pylorus 
 opens, and the liquefied mass begins to flow into the intes- 
 tine. The absorption from the intestine no longer fur- 
 nishes material for the secretion of pepsine, and hence, as 
 the food passes out of the stomach, the pepsine gradually 
 ceases to be formed, what has already been secreted is 
 consumed, and finally, at the end of digestion, i. e. four 
 or five hours after a solid meal, the stomach is completely 
 deprived of it. 
 
 In milk babies may be said to eat their soup and meat 
 together, and the amount of soluble material is so large that 
 its absorption rapidly furnishes enough pepsine to digest 
 the comparatively small amount of caseine. The mode of 
 secretion of the acid of the gastric juice is less well known 
 than that of the pepsine. According to some observers, 
 
TO INFANT DIET. 
 
 it is formed in the pepsine glands, but in a different set 
 of cells from those secreting the pepsine. According to 
 others, special glands exist for the acid, lying in the right 
 or pyloric half of the stomach, and called the mucous 
 glands. The general shape of these glands resembles 
 that of the others, but the cells are like little prisms, 
 ranged along the wall, instead of irregular polygons, 
 blocking up the entire cavity. They secrete mucus, and 
 it is said that this mucus decomposes the salt of the food, 
 chloride of sodium, and thus forms hydrochloric acid. 
 (Beneke.) The acid and the pepsine are dissolved out 
 from the recesses of the glands by the water contained in 
 the stomach, and brought together by the same medium, 
 to act simultaneously upon albumen. Neither alone has 
 any true digestive action : non-acidified pepsine and non- 
 peptic acid are equally powerless. Finally, both require 
 to be largely diluted by water. When they are too con- 
 centrated, the process of digestion is at once arrested, but 
 can be renewed, as already said, merely by the addition 
 of water. 
 
 These facts show why, contrary to a common preju- 
 dice, diluted food is more nourishing to the baby than 
 solid. They show also the bad effect of excessive cutane- 
 ous perspiration in hot weather, when so much water is 
 evaporated by the skin that not enough is left to dilute 
 the gastric juices, and hence the curds remain undigest- 
 ed and are vomited. They show why concentrated milk 
 
INFANT DIET. 71 
 
 is difficult of digestion, and the reason for the injurious 
 effect upon the child of the several circumstances we have 
 noted which tend to diminish the water of the mother's 
 milk, as hot weather, fever, menstruation. They show 
 also an unexpected evil result of too frequent nursing, 
 which, as we have seen, renders the milk too concen- 
 trated. In adults, liquids are often more difficult of di- 
 gestion than solids. In that case there is always in the 
 stomach too small an amount of acid, which becomes 
 unduly diluted by water. The right proportion is about 
 four parts to one thousand of water. We have seen that 
 one great advantage of liquid food was that it increased 
 the amount of pepsine. To increase the amount of acid, 
 solid food is preferable, for it irritates the mucous mem- 
 brane, and hence stimulates the mucous glands where the 
 acid is formed. In babies, with a natural tendency to a 
 surplus of fermenting mucus, and excess of acid, this irri- 
 tation is always to be avoided. 
 
 It is in this great tendency to acid fermentations that 
 we find the second reason for the exclusion of starch from 
 infant diet. We have shown that the natural modifica- 
 tion of starch by saliva is a kind of fermentation, and 
 which, if not arrested at precisely the right point, will 
 give rise to the formation of acids. In all digestions an 
 excess of acid is as injurious as a deficiency, and this is 
 especially true in the digestion of milk, owing to the pe- 
 culiar effect of acid upon the caseine. 
 
72 INFANT DIET. 
 
 This leads us to speak of the third peculiar charac- 
 teristic of milk, the presence in it of caseine. This is the 
 albuminous substance of the milk, but it is different in 
 many respects from albumen of meat, of eggs, etc. The 
 albuminous material of meat is solid, and when attacked 
 by the gastric juice it becomes softened, disaggregated, 
 and finally dissolved. This solid albumen may be also 
 dissolved in very dilute solutions of ordinary acids, but if 
 these are at all concentrated, it is coagulated instead of 
 being dissolved. Finally, even from these dilute solu- 
 tions, it is at once precipitated if the acid be neutralized 
 by the addition of an alkali. In healthy gastric juice, 
 where the acid is always associated with pepsine, the 
 albumen is not only dissolved but transformed, so that 
 it will not precipitate when the acid is neutralized. 
 Were it not for this transformation, which renders the 
 albumen permanently liquid, it would precipitate from 
 the solution as soon as this passed into the blood, which 
 is alkaline, and solid particles would be carried into the 
 capillaries and block them up. When the gastric juice 
 contains an abnormally large amount of acid in propor- 
 tion to its pepsine, the albumen is indeed often coagu- 
 lated instead of dissolved, and hence becomes a cause of 
 irritation and of dyspepsia. 
 
 Liquid albumen, as that of eggs, does not coagulate 
 in the stomach, unless the acid be unduly concentrated. 
 It is modified or "digested" by the pepsine, in essen- 
 
INFANT DIET. 73 
 
 tially the same way as solid albumen, and requires much 
 move acid for its digestion than the latter. Caseine dif- 
 fers from liquid albumen, by coagulating as soon as 
 it comes in contact with the dilute acid of the gastric 
 juice. The milk " curdles" in the baby's stomach in the 
 same way that it does in a porringer when a thunder- 
 storm has caused its sugar to ferment and generate lactic 
 acid. Upon the nature of the acid thus formed depends 
 some of the principal varieties in the digestibility of the 
 milk. Herein lies the most essential difference between 
 human milk and cow's milk, and on it depends the fre- 
 quent indigestibility of the latter. The caseine that has 
 been coagulated by the acid of the gastric juice must be 
 so modiiied by the pepsine that it redissolves again, or 
 rather decomposes into two or three substances, of which 
 some are soluble and others are not. 
 
 The soluble products of the modified albnmoids are 
 called peptones ; the insoluble, parapeptone. This latter 
 passes into the intestine to be digested. During the 
 digestion of milk a substance is formed, intermediate 
 between the caseine and the peptone, called metapeptone. 
 The peptones, dissolved in the gastric juice, cannot be 
 precipitated from it when its acidity is neutralized by the 
 addition of an alkali. This, as we have already said, is 
 the very peculiarity which distinguishes the solution of 
 albuminous substances in gastric juice from their solution 
 in ordinary acids that do not contain pepsine for from 
 4 
 
74 INFANT DIET. 
 
 these they are readily precipitated. The metapeptone, 
 destined ultimately to be converted into peptone, also 
 remains dissolved when an alkali has been added to the 
 solvent gastric juice ; but if an excess of acid be added, it 
 immediately precipitates. It is precisely this precipita- 
 tion by an excess of acid which is a frequent cause of 
 vomiting in babies at the breast : the curds they reject 
 in such abundance shortly after nursing, consist of meta- 
 peptone. They do not therefore result from the first 
 coagulation of the milk, but from a precipitation of that 
 which has been partially digested. 
 
 The parapeptone, or the insoluble substance formed at 
 the same time as the peptone, is never changed into pep- 
 tone, but precipitated as soon as the acidity of the gas- 
 tric juice begins to diminish, as it always does towards 
 the end of digestion. The acid becomes saturated by the 
 substances it has attacked, and can only retain in solution 
 those which have been rendered permanently soluble by 
 the pepsine. The parapeptone therefore gradually accu- 
 mulates in the stomach, and finally passes into the intes- 
 tine, where its digestion is completed. The longer the 
 parapeptone stays in the stomach, the more insoluble it 
 becomes ; and if it stays too long, it will become changed 
 into still another substance, of the consistency of soap, 
 and called dyspeptone. This constitutes a second kind 
 of curd, which irritates the stomach much more than the 
 metapeptone, giving rise to an excessive secretion of acid, 
 
INFANT DIET. 75 
 
 just as a stone would do. This acid is not gastric juice, 
 for it contains no pepsine ; it cannot therefore digest — it 
 only coagulates all coagulable materials into firmer clots, 
 and these, after much pain and disturbance, are finally 
 rejected by vomiting. This vomiting is therefore of dif- 
 ferent origin and of much greater severity than that 
 which occurs in the early stages of digestion, very soon 
 after the child has taken the breast. The first results 
 from the precipitation of the metapeptone by a slight 
 excess of acid, that is, when there is only a little more 
 acid in the stomach than can be saturated by the food it 
 digests. This may occur with little variation from per- 
 fect health : the baby vomits, yet shows no sign of discom- 
 fort. But dyspeptone is only formed when the curds 
 first coagulated are so tenacious that they can only be 
 slowly redissolved. The digestion is slackened, the in- 
 soluble substances, parapeptones, do not pass readily into 
 the intestine, and, staying too long in the stomach, become 
 the more indigestible dyspeptone. There is therefore a 
 true indigestion, with all its symptoms and consequences. 
 The slight excess of acid, consequent precipitation of 
 metapeptone, and easj r vomiting, may be occasioned by, 
 1st, an excessive secretion from the mucous glands, which 
 mucus readily ferments, and then decomposes too much 
 sugar and salt, so that too much lactic, acetic, and hydro- 
 chloric acids are generated. Some children, those called 
 " lymphatic " or " scrofulous," are especially predisposed 
 
76 INFAKT DIET. 
 
 to this excessive secretion, not only in the stomach, 
 but on all the mucous membranes, as the eyelids, nose, 
 bronchial tubes. 
 
 2d. The milk may contain too much caseine for the 
 amount of water. Too little soluble material will be 
 absorbed from the stomach in the first time of digestion 
 to furnish enough pepsiue to transform all the caseine in 
 the second time. There will be therefore too little pep- 
 sine in proportion to the acid of the gastric juice, or, in 
 other words, the acid will be in slight excess. 
 
 3d. The total amount of milk may be in excess, or 
 the child may have swallowed more than its stomach is 
 able to furnish pepsine enough to digest. The facts we 
 have mentioned in regard to the anatomy of the stomach, 
 and the small development of its fundus or peptic-gland 
 portion, show why the pepsine is so much more liable to 
 be deficient in the gastric juice, than the acid. Exces- 
 sive feeding in babies nearly always means too frequent 
 feeding, and in babies at the breast this determines a 
 special cause of vomiting. It is a rather singular, but 
 well-proven fact, that the longer the milk remains in the 
 breast the more watery it becomes. Conversely, when 
 milk has recently been secreted under the stimulus of 
 suction at the nipple, it is much richer in solid consti- 
 tuents, especially in caseine and butter. A baby that 
 nurses too often is thus exposed to a special cause of indi- 
 gestion : the food is rendered more concentrated and dif- 
 
INFANT DIET. 11 
 
 ficult of digestion, at tlie very time that the digestive 
 powers are weakened by excessive use. A newborn in- 
 fant should not be nursed oftener than once in two hours, 
 and the daily meals of a child of eight or ten months 
 should not exceed five in number. It often suffices to 
 render the meals even less frequent, to allay vomiting 
 caused by too rich milk. All the above conditions may 
 be present when the child is at the breast, and thus the 
 first kind of vomiting is quite as frequent in nursing 
 children as in those brought up by hand. But the indi- 
 gestion occasioned by the stony masses of dyspeptone is 
 much more often seen when children are fed upon cow's 
 milk. The caseine of cow's milk is more abundant than in 
 human milk, and it coagulates in much firmer clots, which 
 resist disaggregation for a longer time. There is also less 
 sugar in the milk, so that one source of acid (lactic) is 
 curtailed, and the acidity of the gastric juice diminished. 
 On the other hand, there is a larger amount of butter, 
 which is quite indigestible in the stomach, and which, if 
 retained there by a slow digestion, is liable to decompose ■ 
 and generate butyric and other fatty acids. These are of 
 little if any use for acidifying the gastric juice, while on 
 the other hand, they help to coagulate the caseine into 
 tougher masses. "We have already shown that the dys- 
 peptone which finally results from this prolonged diges- 
 tion irritates the stomach, giving rise to a secretion of 
 acid out of all proportion to the pepsine, and constituting 
 
78 INFANT DIET. 
 
 therefore no true digestive fluid. The irritation may bo 
 intense enough to occasion a catarrh of the stomach, or a 
 congestion of its lining coat, accompanied by excessive 
 mucus secretion. By this, the elaboration of pepsine 
 in the peptic glands is diminished, for when there is 
 congestion the blood in the vessels stagnates instead of 
 circulating rapidly to bring new material. For the same 
 reason absorption from the stomach is checked, thus fur- 
 ther diminishing the supply of pepsine, and finally im- 
 pairing the general nutrition of the body. Or, again, 
 the dyspeptone itself may decompose, and generate fat 
 and fatty acids. It will pass the pyloric orifice of the 
 stomach quite unprepared for i-ntestinal digestion, and 
 irritate the intestine so as to occasion diarrhoea. The 
 evacuations consist of mucus and fluids secreted from the 
 intestine, the masses of undigested food themselves pass 
 slowly down the canal, often causing a temporary ob- 
 struction. The slower the progress, the more completely 
 is the water absorbed, constipation succeeds to diarrhoea, 
 and the evacuations become hard and dry. Thus pain in 
 the stomach, vomiting, diarrhoea, constipation, general 
 failure of nutrition may be the result of feeding a young 
 baby upon rich cow's milk, injurious precisely because so 
 rich. Precisely similar disturbance is caused by human 
 milk when the caseine in it is in excess of the normal 
 proportion. With the excess of caseine there is gener- 
 
INFANT DIET. 79 
 
 ally an excess of fat globules, and the milk is remarkable 
 for its whiteness and opacity. 
 
 Besides the above-mentioned forms of vomiting where 
 the milk is curdled, there is another where the milk is 
 rejected almost unchanged. This generally indicates 
 more serious trouble, for it implies a deficiency in the 
 secretions of the stomach, or else an excess of alkaline 
 mucus dependent on catarrh, and which has neutralized 
 the acid. The baby is then generally ill enough to re- 
 quire a physician. 
 
 In all these cases where the caseine of milk passes to 
 the condition of dyspeptone, and remains with water or 
 some watery liquid undigested, the milk must be diluted. 
 This dilution acts in two different ways. In the first 
 place, it favors the absorption of a soluble substance into 
 the blood, and thus provides for the secretion of pepsine 
 to digest the insoluble, the caseine. In .the second place, 
 it dilutes the acid of the gastric juice, and thus prevents 
 it from coagulating the caseine too firmly. In a word, 
 as might be expected, the addition of water to milk helps 
 the digestion in precisely the way that the water origin- 
 ally contained in the milk is intended to do. Where 
 the child is fed by hand, of course the diluting fluid is 
 easily added to the milk in the bowl. "Where it is at the 
 breast, the same end is reached by giving a table-spoonful 
 or more of this fluid just before nursing. Instead of 
 plain water it is preferable to use some substance which 
 
80 INFANT DIET. 
 
 by its physical consistency is able to hold the caseine clots 
 in suspension, thus protecting the lining membrane of 
 the stomach from irritation, while they are being pre- 
 pared for dissolution. Thus may be mixed quite thin 
 and transparent mucilage with (boiled and skimmed) 
 cow's milk, and added the desirable quantity of sugar 
 and salt, or soda. With the caseine of this mixture the 
 gastric juice will get into very slow contact indeed, thus 
 producing a looser, because a more gradual and inter- 
 rupted coagulation, on which the digestive liquids and 
 the peristaltic motion of the stomach have a better op- 
 portunity to exert their influence. Looking for a sub- 
 stance, which, while fulfilling that object, is absolutely 
 indifferent, from a chemical and physiological point of 
 view, it is gum arabic. Its decoction, therefore, as it is 
 not influenced by the digestive liquids, and is not ab- 
 sorbed, acts mechanically only. If I meant to write a 
 eulogy on gum arabic, I should but add, that its unpre- 
 tending and unaggressive nature renders it particularly 
 fit for an addition to children's food, when, in more 
 advanced years also, their irritated intestines reqnire a 
 soothing addition to the necessary nutriment.* 
 
 An indifferent substance of this sort may be all that 
 
 * Dr. Wertlieirn's book on the " Dietetics of Nurslings," pub- 
 lished in Munich in 1860, has greatly encouraged me to insist upon 
 my plan of diluting caseine. Already Van Swieten, in the fifteenth 
 century, recommends decoctions of wheat or barle y for this purpose. 
 
INFANT DIET. 81 
 
 is desired for very young infants : when they advance 
 in weeks and months, they may require a substance, 
 which, while fulfilling the indication of keeping cow's 
 milk suspended, will act as a nutriment at the same 
 time. 
 
 The selection of articles of food, which are, at the 
 same time, of a mucilaginous consistency, and nutrient, 
 is perhaps not so difficult as it appears to be. At all 
 events, we shall have to avoid such farinacea, which, like 
 potatoes, rice, and arrow-root, contain an overwhelming 
 amount of starch and cellulose. All farinaceous food 
 contains, of course, a certain proportion ; but those arti- 
 cles should be selected in which starch is least abundant. 
 However, to the question of the digestibility of amylum 
 by the infant, I shall have to refer again. 
 
 There are a few only of which I make any use in the 
 feeding of infants. To justify my selection, I must — 
 although I have carefully avoided the quotation of fig- 
 ures and statistics — beg your permission for the follow- 
 ing few, which contain in j>er mille the proportions of 
 the constituents in a number of articles : 
 
 Albuminous substances : — In wheat, 135 ; barley 123 ; 
 rye, 107 ; oatmeal, 90 ; Indian corn, 79 ; rice, 51. 
 
 Starch : — In rice, 823 ; Indian corn, 637 ; wheat 
 569 ; rye, 555 ; oatmeal, 503 ; barley, 483. 
 
 Fat : — Indian corn, 48 ; oatmeal, 40 ; barley, rye, 
 wheat, rice, but little. 
 4* 
 
82 INFANT DIET. 
 
 Salts (principally phosphates) : — Barley, 27 ; oat- 
 meal, 26 ; wheat, 20 ; rye, 15 ; Indian corn, 13 ; rice, 5. 
 
 Potassa is mostly found in wheat ; magnesia in wheat 
 and Indian corn ; lime in oatmeal and barley ; iron in 
 barley ; phosphoric acid in barley and wheat. 
 
 From this small list you would exclude, for their 
 large percentage of starch, as regular additions to infants' 
 food, rice and Indian corn. For their large percentage 
 of albuminous substances, you would select wheat, bar- 
 ley, rye, or oatmeal ; for their high percentage of salts, 
 so absolutely required in the healthy organization of the 
 blood, and the rest of the tissues, barley, oatmeal, and 
 wheat. 
 
 Your list would consist of these three, then : barley, 
 wheat, and oatmeal, as possessing all the necessary ele- 
 ments of nutrition, while holding so much amylum as to 
 render it dangerous, when in good preparation. Amongst 
 the three, barley appears to be preferable for its nutri- 
 tionsness and digestibility. Molesehott claims thirty-six 
 ounces a day as a sufficient amount of food for a hard- 
 working man. There is another advantage, I think, it 
 has over the other cereals mentioned, viz. that it bears 
 the removal of the husk, after grinding, better than 
 any other. The large proportion of the proteinous sub- 
 stances in wheat and rye is deposited in the inner layer of 
 the husk, which is not generally used. (Payen.) Not so 
 in barley, where the protein is spread on a larger portion 
 
INFANT DIET. 83 
 
 of the grain. Thus, the husk may be removed, and the 
 consistency made fine, without diminishing, to any con- 
 siderable extent, the nutritive value of its constituents. 
 
 Barley and oatmeal are the two substances I mostly em- 
 ploy, as their chemical constituents are nearly alike, with 
 the exception of a large portion of fat in oatmeal, which is 
 not found in barley. Barley water, or thinned and sweet- 
 ened oatmeal gruel, may be given to the child at the 
 breast as above described. The indications for the use of 
 one or the other lie in the condition of the infant. Where 
 there is a decided tendency to constipation, I prefer oat- 
 meal ; where there is no such tendency, or perhaps even 
 a tendency of the bowels to be loose, I employ barley. 
 The " prepared " barley is a good preparation ; but it is 
 safer, as no mistake or deception can take place, for every 
 mother to grind it in a common coffee-grinder of her 
 own. A teaspoonful of either is boiled in from three to 
 six ounces of water, with some salt, for twelve or fifteen 
 minutes, the decoction to be quite thin for very young 
 infants, thicker for later months, and then strained 
 through a linen cloth. Infants of four or six months are 
 to have equal parts of this decoction, which ought to be 
 made fresh for every meal ; and (boiled and skimmed) 
 cow's milk and sugar is to be added. At an early age, 
 the thin decoction, at "a later, the milk ought to prevail in 
 the mixture, which ought to be given at a temperature of 
 80-90°, ought to be neutralized, when acid, with a few 
 
8i INFANT DIET. 
 
 grains of bicarbonate, or carbonate of potassa or soda, 
 and, until infants are eight or ten months old, thin 
 enough to be taken through a nursing-bottle. 
 
 Liebig recommends a mixture of two pounds of wheat 
 malt and one ounce of carbonate of potassa. Of this 
 mixture a table-spoonful is to be cooked with milk and 
 water. He wishes to develop sugar in and out of the 
 food rather than to add it in substance. The recom- 
 mendation is a good one. But the object of this paper is 
 to show in what manner substances known to, and in the 
 grasp of, every part of our population, can be employed 
 as a perfectly harmless, reliable, nutritious article of diet. 
 
 Such substances must have several qualities. They 
 must be perfectly simple and recognizable. They must 
 be found for sale everywhere. Their preparation must 
 be perfectly simple and easy. 
 
 For this reason I prefer the unground barley to the 
 so-called " prepared " article. For the same reason I can- 
 not encourage the use of patented articles of food, al- 
 though there may be some which deserve attention and 
 credit. I might name some which now and then have 
 proved beneficial in my own hands ; and also some, 
 which, when I had the analysis made of two different 
 bottles of the same box sent as specimens, yielded greatly 
 varying results. Amongst the axioms we ought not to 
 lose sight of is, that unvarying truth is in nature only; 
 and that trade, or money, has no soul nor conscience. 
 
INFANT DIET. 85 
 
 In the preparation of cow's milk, therefore, for the 
 use of habies, it is first necessary to dilute the caseine, 
 then to add to the nutritive material of the milk by the 
 choice of vegetable decoctions iustead of plain water to 
 effect this dilution. These vegetable decoctions, like the 
 milk they dilute, contain albumen, fat, and salts. But 
 instead of sugar they contain starch, destined finally to 
 be changed into sugar, but whose decomposition in the 
 stomach often also gives rise to acids, whieh mix with 
 those of the gastric juice, and increase its effect. But as 
 the sugar obtained from starch cannot supply all the sac- 
 charine matter necessary for the baby, there must be in 
 his food ready-made sugar as well. 
 
 "When speaking of the food of the nursing mother 
 we have already explained some of the peculiar uses of 
 non-nitrogenous substances, that is, fat, starch, and sugar. 
 We have said that they may be compared to the coal 
 that furnishes steam to a locomotive. They do not help 
 to build up the framework of the bodj r , but their com 
 bnstion in the body gives offbeat, and the heat is neces 
 sary on the one hand to all the chemical processes of nutri- 
 tion, and on the other to the evolution of motor force : 
 without which neither the tissues could grow, nor the 
 "muscles contract, nor the limbs move. The body would 
 be an inert mass, like a locomotive whose fuel is ex- 
 hausted. It is not alone by the feeble limbs of a baby 
 that we can measure the muscular force expended in its 
 
86 INFANT DIET. 
 
 little body. There are internal as well as external mus- 
 cles, and before the child can walk the work done by the 
 internal muscles is the most important. The beating of 
 the heart, the expansion of the lungs, the rhythmical con- 
 tractions by which the food is propelled along the ali- 
 mentary canal, all imply incessant muscular contractions. 
 The calculation has been made that the work performed 
 by the heart is equivalent to raising its own weight to 
 nearly five hnndred feet every minute. The muscular 
 force expended in the movements of respiration in the 
 course of the day would suffice to raise to the height of 
 three feet about 24,000 pounds. These calculations are 
 made for the adult, but the difference in the baby is much 
 less than for the voluntary muscles. 
 
 Of the three kinds of food especially destined to fur- 
 nish heat for this enormous amount of motor force- 
 sugar, starch, and fat — the first is directly absorbed from 
 the stomach, the second incompletely modified there, 
 and the third, fat, not digested at all until it reaches the 
 intestine. Since it is desirable that for the baby as large 
 a proportion as possible of the food should be digested in 
 the stomach, sugar is a more appropriate " heat food " 
 than either starch or sugar. Its deficienc} 7 , by curtailing 
 a source of motor force, may cause constipation in another 
 way than that already mentioned, namely, by diminish- 
 ing the motor force of the intestine. In human milk, 
 where there is no starch, there is a much larger propor- 
 
INFANT DIET. 87 
 
 tion of sugar than of butter, while in cow's milk the 
 batter is doubled. 
 
 The relatively small amount of free alkali in cow's 
 milk is a serious drawback, as, sometimes, even fresh 
 cow's milk has no alkaline or neutral reaction, and is 
 very apt to undergo acid decomposition within a very 
 short time, especially during summer. It is advisable, 
 therefore, to add an alkaline salt (the carbonate or bicar- 
 bonate of potassa or soda) to cow's milk, and best at once, 
 when the milk is put aside for the infant's use. Which- 
 ever is selected may not make a great deal of difference 
 under otherwise normal circumstances. Thus, I add 
 1-2 grains of either of the salts to every meal of the new- 
 born, besides a small quantity of common salt — chloride 
 of sodium — and a larger dose in proportion to age. 
 
 The addition of chloride of sodium to the food is the 
 more important the more the milk is mixed with a vegeta- 
 ble decoction. Carnivorous animals crave no salt ; herb- 
 ivorous, however, a great deal, although in their food 
 the absolute amount of chloride and sodium is as large as 
 in that of the former. They are easily drawn by hunters 
 into fields and woods strewn with salt ; and the instinct 
 of mankind has early taught how to add more salt to herb- 
 aceous than to animal food. Liebig has tried to explain 
 this fact by the chemical relation of chloride of sodium 
 to the sugar into which starch has been transformed by 
 the effect of saliva and pancreatic juice. But it appears 
 
88 INFANT DIET. 
 
 that G. Bunge (Zeitschrift fur Biologie, 1873) comes 
 nearer to a satisfactory chemieo-physiological explana- 
 tion. "We find that the craving for salt grows in propor- 
 tion to the amount of potassa salts contained in the food. 
 In the food of herbivores there is twice or even four 
 times as much potassa as in that of carnivores ; potatoes, 
 with their large amount of potassium, combined with 
 chlorine with phosphoric and citric (pomic) acids, necessi- 
 tate the addition of large quantities of chloride of sodium. 
 In the food of carnivores, however, who eat whole ani- 
 mals, one equivalent of potassa is nearly balanced by one 
 of soda and one of chlorine. 
 
 Potassa salts and soda salts both exist in the blood, 
 the former principally in the blood corpuscles, the latter 
 entirely in the serum or watery part of the blood. There 
 is chloride of potassium in both corpuscles and serum, 
 but phosphate of potassa in the corpuscles alone. !Now 
 if there should ever be in the blood more phosphate of 
 potassa than can be taken up by the corpuscles, it will be 
 immediately decomposed by the chloride of sodium in 
 the serum — chloride of potassium and phosphate of soda 
 are formed, and these are both rapidly eliminated by the 
 kidneys, and pass away in the urine. By this means, 
 chloride of sodium is carried away, and must be replaced : 
 in other words, vegetable food requires the addition of a 
 great deal of salt. 
 
 The substitution of cow's milk for woman's milk 
 
INFANT DIET. 89 
 
 necessitates the addition of salt, for a similar reason ; for 
 while 1,000 parts of human milk contain only 0.70 chlo- 
 ride of potassium, 1,000 parts of cow's milk contain 1.30.* 
 
 In this connection, while speaking of different artifi- 
 cial modes of feeding infants, I ought to allude to Lie- 
 big's artificial milk for babies, which deservedly has at- 
 tracted the attention of the world. 
 
 According to Dr. Letheby (Chem: News, Jan., 1869), 
 the food which Liebig recommends for infants is a prep- 
 aration of malt, with wheaten flour and milk, to which a 
 little bicarbonate of potassa has been added. The prep- 
 aration is made by mixing one ounce of wheaten flour 
 with ten ounces of milk, and boiling for three or four 
 minutes ; then removing it from the fire and allowing it 
 to cool to about 90°. One ounce of malt-powder pre- 
 viously mixed with fifteen grains of bicarbonate of po- 
 tassa, and two ounces of water are then stirred into it, 
 and the vessel, being corked, is allowed to stand for an 
 hour and a half, at a temperature of from 100° to 150°. 
 It is then put once more upon the fire, and gently boiled 
 for a few minutes. Lastly, it is carefully strained to re- 
 move any particles of husk, and then it is fit for the 
 
 * When food containing an excess of salt is used, it is necessary 
 to reverse the above process, and add substances which contain po- 
 tassa. Scurvy among sailors has been traced to the use of salt meat, 
 and cured by the. addition of potatoes and other vegetables contain- 
 ing large amounts of potassa, and which carry off the excess of salt 
 in the way described in the text. (Garrod.) 
 
90 INFANT MET. 
 
 child's food. The composition of the food, according to 
 Liebig, is as follows : 
 
 PLASTIC MATTER. CARBONACEOUS HATTER 
 OUNCES. OUNCES. 
 
 
 1.00 
 
 1 " " wheat flour, 0.14 
 
 0.74 
 
 1 " " malt flour. . 0.07 
 
 0.58 
 
 0.61 2.32 
 
 The relation of the plastic to the carbonaceous matter 
 being as 1 : 3.8, which is the right proportion for the 
 food of children. 
 
 The effect of the malt-flour is to transform the starch 
 into glucose, or grape sugar, the only form of sugar as- 
 similable to the tissues, and thus the mixture gets thinner 
 and sweeter as it stands ; and the bicarbonate of potassa 
 is added to facilitate the change and to neutralize the 
 acid constituents of the flour and malt. 
 
 It looks as if the results of this food must be uni- 
 formly good, and still the disappointments in regard to 
 its effects have been as many as its recommendations 
 have been eulogistic. I have employed it myself, with 
 varying results. I believe that the attention required in 
 preparing the food is the source of failures in most cases. 
 Common sense is not at all a prerogative of every mother 
 ■and nurse : and it appears that the requirements laid 
 down in Liebig's plan demand too great a complication 
 of cerebral functions on the part of cooks. The attempts 
 
INFANT DIET. 91 
 
 at shortening this cooking process, by preparing for the 
 market some similar articles requiring less attention and 
 time, are to be ranked amongst the patent merchandise 
 of which I spoke before. It was one of these " prepared 
 Liebig's foods " on which I made the experiments I men- 
 tioned. 
 
 One more word upon the dangers to be guarded 
 against in the use of cow's milk. Of these, the principal 
 that is alleged is, its adulteration by arnylum, gum ara- 
 bic, lime, and other articles. Our country places, how- 
 ever, do not suffer on this account; nor do I believe that 
 much of this sort of adulteration takes place in the city. 
 As the tests for the accused articles are easy, I have fre- 
 quently tested for them, in former years, in different 
 parts of the city, but did not find them.* 
 
 Mixture with water is rather a nuisance than a great 
 danger. But it must be taken into account before dilut- 
 ing the milk, as otherwise this may be unduly deprived 
 of nutritive material. Improper cow's feed is a danger, 
 certainly, but still 1 believe that the large number of 
 
 * Examination for starch or farinacea : — A small quantity of 
 tinct. iod. yields a blue color. 
 
 Gum arabic : — Coagulate milk with acetic acid and filter ; alchol 
 poured into the serum yields a -viscid opaque deposit. 
 
 Soda : — Effervescence in adding acetic acid (vinegar). 
 
 Lime : — Add sulphuric acid and filter ; nitric acid added to the 
 filtered serum, yields a heavy and insoluble deposit of sulphate of 
 lime. 
 
92 INFANT DIET. 
 
 deaths attributed to swill-milk before, during, and after 
 the swill-milk agitation in New York, years ago, are to 
 be sought for elsewhere. 
 
 The desire of parents to procure the milk of one spe- 
 cial cow for their infants, I believe to be based upon a 
 mistake. As we know to what extent chemical and 
 vegetable materials will be eliminated through the milk- 
 glands, in all mammals, we must infer that the milk of 
 each cow possesses a distinct individuality — according to 
 her food, state of digestion, etc. Hence, the child who 
 has become accustomed to one, will suffer from the ab- 
 rupt transition to the milk of another animal — transition, 
 nevertheless, which is often inevitable. There is much 
 less danger in habituating the child to the average milk 
 of all the cows of a farm, as, moreover, the milk of a 
 special cow may, by accidental changes in the food, un- 
 dergo frequent and unexpected changes. I have always 
 advised the plan of giving the average milk of a farm, 
 and have never been sorry for the results, in all parts of 
 the city. Condensed milk, also, is to be recommended 
 in the feeding of infants, the addition of loaf-sugar, that 
 is made in the manufactories, being rather an advantage 
 than otherwise. When it is to be used, it must be di- 
 luted according to the degree of condensation, which is 
 generally from 4 to 5 to 1. 
 
 The above directions are nearly all based upon the 
 changes undergone by the milk in the stomach. Tet, as 
 
INFANT DIET. 93 
 
 we have said, a certain portion of even infants' escapes di- 
 gestion in the stomach and passes on to the intestine, name- 
 ly, all the starch that has not become glucose, all the para- 
 peptone or dyspeptone left from caseine, finally, all the 
 butter, and a certain proportion even of the soluble salts. 
 The digestive apparatus of the intestine is more com- 
 plicated than that of the stomach. Instead of one diges- 
 tive fluid, the gastric juice, there are then the bile, the pan- 
 creatic juice, and the intestinal juice. All the glands of 
 the stomach are contained in the thickness of its mucous 
 membrane ; but the intestine receives two of its true di- 
 gestive fluids from enormous glands lying outside — the 
 liver, furnishing the bile, and thp pancreas. Again, the 
 glands which are imbedded in the intestinal mucous 
 membrane present many more varieties than do those of 
 the stomach. In the first place, there are straight tubes 
 placed side by side like the peptic glands, and lining the 
 entire length of the intestine. These are called the 
 glands of Lieberkuhn. Then there are glands shaped like 
 a bunch of grapes, which are found only in the first part 
 of the intestine immediately succeeding the stomach — a 
 segment about twelve inches long, and on that account 
 called the duodenum. It is into this segment that the 
 bile and pancreatic juice are poured. The grape-like 
 glands are called the glands of Brunner. Then there are 
 little patches called Peyer's patches, made up of groups 
 of small round glands, like little bags : others, similar, are 
 
94: INFANT DIET. 
 
 disseminated here and there. All these glands are found 
 in what is called the small intestine, a tube immensely 
 long in comparison with the size of the body, and which 
 lies coiled up in the centre of the abdomen. At the right 
 side, low down near the hip bone, this tube opens into 
 another, much larger in diameter, and w}th which it com- 
 municates by means of a valve. This larger tube encir- 
 cles the abdomen, and terminates in the rectum and 
 anus. It is called the large intestine. 
 
 Like the small intestine, the large contains glands 
 that furnish a secretion which lubricates the mucous 
 membrane. But it is unnecessary to describe them par- 
 ticularly, for this secre.tion has nothing to do with 
 digestion : it only serves to facilitate the progress of 
 the contents of the intestine, which here become feces, 
 destined for secretion. In the large intestine nothing is 
 digested, but water is continually absorbed from the 
 residue of food, so that the fecal mass assumes continually 
 firmer consistence as it descends the canal. The water 
 is taken up by the veins, just as it is in the stomach, and 
 with the water, all substances directly soluble in it. On 
 this account it is possible to feed a person for a little 
 while by injections of fluids into the rectum. But in re- 
 gard to this matter, a serious oversight is often commit- 
 ted. The rectum and the large intestine absorb, but 
 they do not digest ; that is, they do not transform food 
 into substances that may be assimilated by the tissues. 
 
INFANT DIET. 95 
 
 When substances that have been dissolved, but not so 
 transformed, have passed into the blood, they do not stay- 
 there — they are not assimilated, but pass out unchanged 
 into the urine. If undigested but liquid albumen be 
 thrown into the veins, it appears in the urine ; and so 
 with ordinary sugar. But if digested albumen or grape 
 sugar be injected, there is no trace of a foreign body in 
 the urine. 
 
 When, therefore, on account of his inability to swal- 
 low, or of incessant vomiting, the attempt is made to feed 
 a patient by the rectum, it is necessary not only to dissolve 
 the articles of food, but to effect in them the apparently 
 trifling but really all-important transformations that 
 ordinarily take place in the stomach. Thus sugar and 
 starch must be converted into glucose ; meat or the 
 caseine of milk must be changed to peptone, by means 
 of an infusion of calves-stomach ; fat, which, as we shall 
 show, is digested in the small intestine by means of the 
 bile, the pancreatic and intestinal juice, must be emulsi- 
 fied by the same fluids artificially procured. These pre- 
 cautions are hardly ever taken : if they were, nourish- 
 ment by the rectum would be more often successful— 
 often, indeed, a means of saving life at a most critical 
 emergency. 
 
 There is one other point of great interest in regard to 
 the absorption from the rectum, and that is the increased 
 secretion of pepsine that may be determined by such 
 
96 INFANT DIET. 
 
 injections, as has already been described. We have said 
 that a remarkable efficacy for this purpose attached to 
 a substance called dextrine, a carbohydrate into which 
 starch changes before it becomes sugar. 
 
 In many cases of vomiting that depend upon an in- 
 sufficient formation of pepsine, injections of solutions of 
 dextrine will enable the stomach to resume its functions. 
 This remedy, recommended by Schiff, has not, that I 
 know, been applied to the treatment of gastric indiges- 
 tion in babies, but it would be most rational to do so. 
 
 The apparatus for absorption in the small intestine is 
 more complicated than in any other part of the aliment- 
 ary canal. The glands of which we have spoken do 
 not open upon a comparatively smooth surface* as in 
 the stomach, but underneath and between an innumera- 
 ble multitude of comical projections from the mucous 
 membrane, called villosities. We have already compared 
 these to the rootlets of a plant, which reach down into 
 the soil to absorb the nourishment. Their number is 
 prodigious. 
 
 Each little cone consists of a network of blood-ves- 
 sels held together by fine fibres entirely covered with a 
 layer of prismatic cells, and traversed by a central canal. 
 Under the microscope the villus looks like the finger of 
 a glove. The fluids contained in the cavity of the intes- 
 
 * Leaving out of sight, for the moment, the folds of the mucous 
 membrane. 
 
INFANT DIET. 97 
 
 tine that have been sufficiently prepared for absorption, 
 pass through the cells, and thence into the blood-vessels 
 or into the central canal. Into the first pass materials 
 that are or have been rendered soluble in water, and 
 which can traverse the walls of the blood-vessels by en- 
 dosmosis. Into the central canal passes the insoluble 
 fat, that, by intimate mixture with the three digestive 
 fluids of the intestine, and especially with the bile and 
 pancreatic juice,,has been made into an emulsion. In 
 this state the particles of the fat are very finely divided 
 and suspended in fluids in which it could not dissolve, 
 just as oil is suspended by mucilage or the yolk of an 
 egg. This white fatty emulsion is called chyle, and its 
 infinitesimally fine particles force their way through the 
 walls of the cells (the epithelium) covering the villosity, 
 and so into the central canal called on that account the 
 chyliferous or lacteal vessel. 
 
 Another part of the fat, instead of being emulsified, is 
 saponified. . All fats are composed of two substances — 
 glycerine, with which every one to-day is familiar, and 
 one or more acids, called fatty acids. When oil is mixed 
 with an alkali, as soda or potassa, it is decomposed. The 
 alkali combines with the acid to form a salt which is sol- 
 uble and easily absorbed, and the glycerine forms com- 
 pounds with phosphoric acid. 
 
 All the fluids of the intestine are alkaline, as those of 
 the stomach are acid. In this way everything which has 
 5 
 
98 INFA2STT DIET. 
 
 escaped digestion in the stomach is immediately brought 
 into contact with fluids of exactly opposite chemical 
 reactions. The bile contains abundance of soda and 
 potassa, and the pancreatic juice also. When there are 
 not enough phosphates in the food, the pancreatic juice 
 acts imperfectly on the fats, and thus when the milk 
 is poor in these important salts the butter is imperfectly 
 digested. 
 
 When there is enough alkali to decompose the fats, 
 but not enough to combine with the fatty acids thus 
 set free, these remain in excess in the intestines. They 
 turn the yellow coloring matter of the bile green, and, 
 as has already been said, the passages with which the 
 bile is mixed become green, and thus offer the first indi- 
 cation of deranged digestion. But if the acids become 
 more abundant, they may succeed in neutralizing the 
 alkalinity of the three great digestive fluids, the bile, 
 pancreatic juice, and intestinal secretion. As a first 
 result, fat can no longer be emulsified nor absorbed, 
 and decomposing in the intestine, generates new acids. 
 Further, the presence of the bile seems to be especially 
 necessary to prevent the putrefaction of the food. When 
 there is an excess of acid, less bile is poured out, perhaps 
 because less fat is absorbed from which the bile may be 
 made. In its absence, part of the food does putrefy, gen- 
 erating gases that painfully distend the bowels, causing 
 " wind colic." 
 
INFANT DIET. 99 
 
 Anything that deranges the chemical composition of 
 the intestinal fluids is liable to produce a similar effect ; 
 for in the intestine, whatever food is not digested 'tends 
 to putrefy and generate gases. 
 
 This generation of acids and gases in the intestine is 
 much more frequent in babies than in adults. Colic and 
 diarrhoea are as common accidents during the process 
 of intestinal digestion as is vomiting while the food 
 remains in the stomach. This shows that the intes-. 
 tine, like the stomach, differs notably from that of the 
 adult. The following are the principal points of dif- 
 ference : 
 
 1st. The mucous membrane of the bowel in children 
 
 secretes an abundant mucus, which is liable to ferment 
 
 * 
 and form acids that neutralize the alkalinity of the diges- 
 tive fluids, interrupt the digestion, and thus permit the 
 food itself to decompose into acids. These have therefore 
 a double origin. 
 
 2d. The food of young babies, milk and farinaceous 
 substances, decomposes with especial facility, and the 
 products of decomposition are all acid. The starch that 
 has escaped complete digestion by the saliva, and which 
 is not entirely transformed by the pancreatic juice, gives 
 rise to lactic acid. Butter, in the least excess, will de- 
 compose into butyric, acetic, caproic, and other acids. 
 Gaseine that has staid long enough in the stomach to 
 be changed to. dyspeptone (see p. 00) is with difficulty 
 
100 INFANT DIET. 
 
 attacked by the intestinal fluids, and having irritated the 
 stomach, decomposes in the intestine. 
 
 3d. It is probable that all the glands which supply 
 the- intestine are yet incompletely developed in young 
 babies, so that their secretions are less well adapted for 
 digestion than in adults. We have already spoken of the 
 experiments which show that the pancreas acquires its 
 power of digesting starch even later than the salivary 
 glands. The liver, relatively larger before birth than 
 at any time afterwards, is very large in young babies. 
 But the liver has many other functions besides that of 
 the secretion of bile. It manufactures grape sugar, that 
 passes into the blood, and in the foetus is found in all 
 young and rapidly growing tissues, just as fat is in after 
 life. At this time, moreover, if not always, it is con- 
 cerned in the formation of red blood corpuscles. While 
 these two functions, and possibly others as well, are so 
 active, it is not improbable that the third, with which 
 the adult liver is most popularly identified, should be 
 imperfectly performed, and that the bile should be a less 
 perfect digestive fluid. The bile is partly composed of 
 waste elements, destined to be thrown out of the body, 
 and there is comparatively less waste in the body of a 
 rapidly growing child than in an adult who has ceased 
 to grow. There is therefore less to make bile of. But 
 in the absence of bile^ the contents of the intestine 
 are 1'iable to decompose and generate gases. Of the 
 
INFANT DIET. 101 
 
 small glands imbedded in the walls of the intestine, 
 some are well developed at birth, but others not till long 
 after. The groups called Peyer's patches are very imper- 
 fect — so much so that they are not liable to disease ; and 
 typhoid fever, in which they are invariably inflamed, is 
 extremely rare in young children. 
 
 4th. The digestive apparatus of babies is much less 
 under the control of the brain and spinal cord than is 
 that of adults. In exactly what this control consists, 
 would be difficult, in our present state of knowledge, to 
 define, and still less explain within the compass of this 
 essay. But this much is certain : when anything has 
 weakened the central nervous system, that is, the brain 
 and spinal cord, acids and gases are very apt to form in 
 the intestine. Thus in adults, after great bodily fatigue 
 or mental exhaustion, arrest of digestion, cramps, disten- 
 sion of the abdomen by wind, are common occurrences, 
 especially in women, and above all in hysterical women, 
 in whom the brain and spinal cord are incapable of much 
 endurance. We must infer that under these circum- 
 stances there has been an insufficient secretion of diges- 
 tive fluids, so that the food has been left to itself, to un- 
 dergo spontaneous decomposition or acid fermentation. 
 In babies, the brain and spinal cord are incompletely de- 
 veloped, and their control over the intestine is therefore 
 permanently as weak as it occasionally becomes in adults. 
 When the nervous system is further weakened by the 
 
102 INFANT DIET. 
 
 Iieat of summer, the tendency to acid fermentations in 
 the intestine is increased, and this is one reason why- 
 diarrhoea is so frequent a disease of children in summer. 
 
 The same weakness of the nervous system may be- 
 come a cause of diarrhoea in another way, namely, by 
 an increased rapidity in the movements of the bowels. 
 There are certain nerves that run from the spinal cord to 
 the intestine, whose action, when powerful, tends to mod- 
 erate these movements, but if it be weakened, the bowel 
 contracts irregularly and precipitately, and propels its 
 contents so rapidly that the food does not have time to 
 digest. The surface of the bowel is irritated by the un- 
 digested lumps that pass over it, and pours out watery 
 secretions ; the passages become frequent, and contain at 
 once the undigested food, abundant liquid, and- slimy 
 mucus. Thus diarrhoea, that may result from so many 
 other conditions, may be set up merely by the exhaustion 
 of the nervous system that results from heat. 
 
 As the disorders of the stomach in babies may be ap- 
 proximatively estimated by the nature of the vomiting 
 which is their first symptom, so the various derangements 
 in the intestinal digestion may bo classed according to 
 the nature of the stools. We will recapitulate in a few 
 words what has been said on this subject. When the 
 passages are green, there is an excess of acid in the intes- 
 tine, that has changed the yellow coloring matter of the 
 bile. This excess of acid always comes from a fermenta- 
 
INFANT DIET. 103 
 
 tion of some part of the food that has escaped digestion — 
 starch, giving lactic and acetic acids ; butter, giving buty- 
 ric and other fatty acids, and dyspeptone, from the case- 
 iue, M-hich finally decomposes into acid similar to those 
 coming from fats. The fermentation may be caused by 
 an excess of decomposing mucus. 
 
 All the digestive fluids of the intestine are alkaline. 
 When part of the food becomes acid and neutralizes this 
 alkalinity, the digestion of another part is therefore 
 arrested. 
 
 These acid passages excoriate the nates, and occasion 
 red eruptions. In bad' cases the mouth often becomes 
 sore. When the acids thus formed pass into the blood, 
 they tend to dissolve and carry off the phosphates, and 
 thus to interfere with the building up of tissues, and 
 especially of bones. 
 
 When the passages are watery and yellow instead of 
 green, they indicate too rapid peristaltic movements of 
 the bowels, with excess of secretion. 
 
 These rapid movements always imply a weakening 
 of the spinal nerve influence distributed to the bowels. 
 When the stools are entirely watery, this is often the 
 cause of the trouble. When lumps of hard curd are 
 found in the passages, the cause of the diarrhoea is gen- 
 erally the irritation of the bowel by caseine that has 
 escaped digestion in the stomach, and become too indi- 
 gestible for the intestine. 
 
104 INF-SKT DIET. 
 
 "Watery, colorless, and very frequent stools indicate 
 a peculiar irritation of the bowels that may become 
 extremely dangerous, or already indicate the beginning 
 of cholera infantum. In this disease, all the secretions 
 of the intestine are arrested, including the bile ; the fluids 
 of the stools are poured out from the blood-vessels. By 
 a diarrhoea of this kind the system may be drained as by 
 a hemorrhage. The treatment of such grave disorder 
 belongs entirely to the physician. 
 
 The green, watery or lumpy passages may sometimes 
 be remedied by the mother. Chalk-powder and carbon- 
 ate of magnesia are remedies much used to directly neu- 
 tralize the acid ; subnitrate of bismuth, in rather large 
 doses, has a very remarkable power to arrest the ferment- 
 ing process that gives rise to acids.* When, instead of 
 diarrhoea, there is constipation, and the green stools are 
 infrequent and accompanied by pain, soda or magnesia 
 or bicarbonate of potassa are selected to neutralize the 
 acid, for they do not constipate, as the chalk and carbon- 
 ate of magnesia do. 
 
 Whenever cow's milk is used for babies, 1-2 grains 
 of bicarbonate of soda or of potassa should be added to 
 each meal. Still better is it to add a teaspoonful of lime- 
 water to each pint of milk that is obliged to stand for 
 
 * Eustace Smith strongly recommends, in addition, aromatic? 
 which stimulate the intestine, as the aromatic powder of the Phar- 
 macopoeia, containing cinnamon, ginger, cardamom, and nutmeg. 
 
INFANT DIET. 105 
 
 several hours, and which is always liable to become acid 
 while standing. 
 
 In very young babies, green stools frequently depend 
 on an irritation of the mucous membrane, and abnormal 
 secretion of mucus. They may be remedied by injec- 
 tions of mucilaginous decoctions, which soothe this irrita- 
 tion, as decoction of marsh-mallow, slippery elm, starch, 
 or gum arabic. 
 
 The lumpy stools must be treated by methods calcu- 
 lated to dilute the caseine and render it more digestible 
 by the gastric juice. The dilution of the milk in the 
 way already described is always necessary in these cases. 
 Afterwards, means for increasing the amount of pepsine 
 in the stomach may be employed. Pepsine may be given 
 with milk, or the method of Schiff adopted, of injections 
 into the rectum of dextrine, that, being absorbed, will fur- 
 nish material for the secretion of pepsine. 
 
 The watery stools, without lumps, often depending 
 upon a depressed condition of the nervous system, require 
 tonic treatment. Cold bathing and change of air are the 
 most important domestic remedies for this purpose. In 
 very hot weather, a few drops of brandy should be given, 
 as will be described further on. When a gastrointes- 
 tinal catarrh has been set up, that is, when the mucous 
 membrane of the bowel has been irritated so as to pour 
 out abundant mucus or "slime," medical advice must 
 always be sought. In these cases the child must be de- 
 5* 
 
106 INFANT r>IKT. 
 
 prived of all food for three, six, or ten hours, and after- 
 wards the quantity of milk must be reduced for several 
 days. 
 
 In all cases of infantile diarrhoea, warm poultices 
 should be applied to the abdomen. 
 
 How are babies to be fed, from a spoon, cup, or nurs- 
 ing bottle ? The only physiological method consists in 
 employing the latter. Neither spoon nor cup prevents 
 food of too hard a consistency from entering a baby's 
 stomach. The fine preparation of the infant's food is 
 equivalent to an adult's careful mastication. The great- 
 est mistake on the part of mothers and nurses is that 
 thick food is more nutritious ; the truth is, that the nutri- 
 tive power of food grows, ceteris paribus, with its dilu- 
 tion. Besides, the main requirement for a normal 
 digestion is a gradual introduction of food into the 
 digestive organs. Gastric disorders are, at every age, 
 the legitimate result of hasty deglutition. The secretion 
 of gastric juice taking place gradually, ought to find for 
 its function but a corresponding amount of food. More- 
 over, the act of sucking itself is indispensable for a suffi- 
 cient secretion of the digestive fluids. The digestive 
 duct is an anatomical and physiological contiguity from 
 lip to rectum. The sucking movement excites the flow 
 of such saliva as is formed in the salivary glands, and 
 also stimulates the rest of the digestive glands. Thus a 
 
INFANT DIET. 107 
 
 healthy digestion requires that food should pass the 
 anterior portion of the digestive tract slowly, and that, 
 for universal use, the nursing bottle should not be dis- 
 pensed with before a sufficient number of teeth enable 
 an infant to masticate. The importance of this physio- 
 logical fact has been well appreciated, although sometimes 
 exaggerated. Thus, Thomas Ballard, a dozen years ago, 
 tried to attribute almost all the diseases of young infants, 
 and even some of their mothers, to " fruitless sucking " 
 on empty breasts, fingers, etc. If it was his intention 
 to impress upon the minds of his readers the close physi- 
 ological connection of all the parts of the digestive tract 
 with each other, we can well afford to overlook the 
 extravagant conclusions of many of his statements. 
 
 To what extent do these general rules of infant diet 
 require modification during the heats of summer ? 
 
 It is well known that summer is the period of the 
 largest infant mortality ; also that this is principally due 
 to affections of the digestive organs; finally, that the 
 prevalence and severity of such affections is, other things 
 being equal, in proportion to the degree of heat. Children 
 are not often killed directly by heat, as are adults — they 
 are not sufficiently exposed to the sun to succumb to the 
 effects of insolation. They do not die merely because 
 they are hot, for they do not get hot enough to die from 
 rise of temperature alone ; but they die when the heat 
 has weakened the digestion, reduced nervous force, and 
 
108 
 
 INFANT DIET. 
 
 thus paved the way for gastrointestinal catarrh and 
 cholera infantum. How does heat do this ? The tem- 
 peratures to which the children we are considering are 
 exposed, range from 90° to 102° at the hottest. Now, 
 even should the temperature of the body reach this lat- 
 ter point, the rise would be insufficient to cause the 
 coagulations of myosine (Kuhne), the paralysis of the 
 cardiac fibre (Obemier), the expansion of the gas of the 
 blood (Eulenburg and Vohl), that have been affirmed or 
 observed in cases of sunstroke. Still less need we ex- 
 pect the multiple fatty degenerations known to be the 
 invariable consequence of a long-continued excess in the 
 production of animal heat. But in the majority of cases 
 in question, the temperature of the body does not rise in 
 proportion to the external heat. The variations are much 
 more delicate than in cases of sunstroke or fever, and 
 accompanied, not by structural lesions, but by the func- 
 tional alterations of nutrition that necessarily precede 
 such lesions. These latter serve, like the magnified dia- 
 grams on a lecture screen, to indicate the nature of 
 changes whose real proportions are too subtle to be 
 appreciated except by inference. 
 
 In relation to the effect of an external rise of tempera- 
 ture upon the lining of the body, three points may be 
 considered established : 
 
 1st. The external temperature primarily affects cutane- 
 ous sensitive nerves. 
 
INFANT DIET. 
 
 109 
 
 2d. The internal temperature of the body is modified 
 by the reflex action of certain parts of the nervous sys- 
 tem, to which the cutaneous impression has been trans- 
 mitted. 
 
 3d. The variations of internal temperature are accom- 
 panied by, if they are not dependent on, modifications 
 of the nutritive processes. These latter are measurable 
 by differences in the consumption of oxygen, and elim- 
 ination of carbonic acid gas. 
 
 The excitation, of the cutaneous nerves is in propor- 
 tion to the difference between the temperature of the 
 animal body and that of the surrounding medium. 
 When an animal is plunged into a bath of cold water, 
 or cold air, there is at first a refrigeration of the surface 
 which communicates a portion of its heat to the medium. 
 In a very short time, however, there is a rise of the in- 
 ternal temperature, as measured by a thermometer placed 
 in (Liebermeister) the axilla or rectum. This rise com- 
 pensates for the loss of heat by radiation, and thus serves 
 to maintain the so-called constancy of temperature of 
 warm-blooded animals, — constancy, however, which has 
 been shown to include variations of two or three degrees 
 (Kichardson). At the same time, with that rise of tem- 
 perature, there is an increased metamorphosis of tissue, 
 indicated by an increased consumption of oxygen, and 
 increased elimination of carbonic acid gas. As the phy- 
 sical and chemical action of cold gives no explanation of 
 
110 INFAJJT DIET. 
 
 the rise of temperature determined by it, we must 
 ascribe the increase of heat to this very increase of 
 molecular metamorphosis, and that, again, to the reflex 
 stimulation of some part of the nervous system. The 
 direct effect of cold is to depress nutritious activity, that 
 is, whenever the temperature of the blood is lowered. 
 The same mechanism that prevents this temperature 
 from following the variations of the external medium, 
 secures a result precisely the reverse of that which would 
 be the direct effect of cold, namely, increased activity of 
 nutrition (Roehrig and Guntz). Precisely the reverse 
 effects are produced by a warm internal medium. "When 
 a guinea-pig was kept in a bath whose temperature 
 gradually fell from from 42.9 to 40.8 (centig.), there was 
 a marked diminution in the consumption of oxygen and 
 in the elimination of carbonic acid. At the same time, 
 the internal temperature rose. During foetal life, where 
 there is no difference between the temperature of the 
 surface of the body and of the surrounding medium, the 
 destructive metamorphosis of tissue is very slight, but 
 the temperature is maintained by the influence of the 
 medium ; also by the predominance of the chemical 
 action of combination over that of decomposition. 
 " Heat is evolved when substances combine ; it becomes 
 latent when substances decompose." But at the very 
 moment that the child by birth is transferred to a medi- 
 um of varying temperature, it is also provided with a 
 
INFANT DIET. HI 
 
 mechanism which constantly compensates for loss of heat 
 from the surface by increased production of heat at the 
 interior of the body. The same cold air that cools the 
 skin excites the sensitive nerves, and this excitement, in 
 one way or another, determines, as we have seen, in- 
 creased metamorphosis of tissue and rise of internal 
 temperature, the latter phenomenon being partly at least 
 dependent upon the former. 
 
 The same modifications, that are determined precisely 
 by experiments with the cold or warm bath, take place 
 spontaneously in summer or winter. The body loses 
 weight from October to April, and gains from May to 
 August. In March the loss is equal to 0.95 ; in August, 
 the increase is equal to 0.70 (Richardson).* This shows 
 that the metamorphosis of tissues is rapid in cold weather, 
 when the cutaneous nerves are stimulated by a marked 
 difference between the temperature of the skin and that 
 of the atmosphere ; while in warm weather, when the 
 difference between the body and its medium is greatly 
 diminished, those same nerves remain unexcited, and 
 the metamorphosis of tissue is- slackened. 
 
 When the waste of tissue is diminished, the ne- 
 cessity for new supply is diminished— -pari passu — 
 the appetite is less, and the vigor of all the processes 
 of nutrition suffers. It is on this account that the 
 
 * These effects in the human being are modified, however, by the 
 increased quantity of food taken in cold weather. 
 
112 INFANT DIET. 
 
 digestive organs are particularly liable to derange- 
 ment in hot weather, or in a more tropical climate 
 than that to which the individual was born, and 
 to which his nervous system is naturally adjusted. 
 When the heat becomes excessive, the cutaneous 
 nerves do not merely suffer from loss of their 
 appropriate stimuli, — they are exhausted. The pro- 
 perties of sensitive nerves are very rapidly exhausted 
 by heat, as may be shown by experiment. Excessive 
 heat will determine anaesthesia, as complete as that 
 induced by chloroform, and the movements of the 
 heart are arrested in tetanus. The spontaneous eleva- 
 tion of atmospheric temperature never, of course, is 
 sufficient for such extreme effects; but a degree of 
 exhaustion of the nerves far below the point of anes- 
 thesia, or of enfeeblement of cardiac contractions, far 
 removed from their complete arrest, is still sufficient to 
 greatly interfere with the nutritive processes dependent 
 on the integrity of nerves and heart. 
 
 That the action of heat and cold upon the body is 
 effected by means of the sensitive nerves, is shown by 
 the analogy between irritation of heat and cold, and that 
 determined by other irritations of moderate intensity. 
 A sea-water bath increases the oxydation processes more 
 than a bath of fresh water. But very violent irritations 
 of sensitive nerves, as by traumatisms or direct applica- 
 tion of electricity (Heidenhain), cause a fall of internal 
 
INFANT DIET. 113 
 
 temperature, and the same thing happens after section 
 of the spinal cord, or certain lesions of the medulla 
 (Tscheschin). This same section is however followed 
 by an elevation of cutaneous temperature, from paralysis 
 of the vaso-motor nerves (Brown Sequard). The internal 
 and external temperature of the body does not, therefore, 
 always correspond ; on the contrary, fever has even been 
 defined by certain authors to essentially consist in the 
 withdrawal of heat from the interior, to be distributed 
 at the periphery. This can only be considered an im- 
 perfect statement of the fact, that in fever the elimina- 
 tion of heat from the surface is diminished, as it is when 
 the body is surrounded by an atmosphere approaching 
 its own temperature. Heidenhain has found that irrita- 
 tion of the sciatic nerve produces a greater fall of 
 temperature, when the animal is plunged into a cold 
 bath at the time of the experiment. If fever has been 
 previously induced by the injection of pus, no fall of 
 temperature can be obtained by irritation of the sciatic, 
 unless the animal be in the bath. The author infers 
 that, in health, irritation of the sensitive nerves acts by 
 quickening the circulation on the periphery (stimulating 
 the peristaltic contraction of the small blood-vessels), so 
 that more blood is brought to the surface to be cooled. 
 In fever, where the blood-vessels of the periphery are 
 passively dilated, the blood stagnates instead of circulat- 
 ing, and the heat evolved by destructive metamorphosis 
 
114 INT ANT DIET. 
 
 of tissue is so great as to annul the effect of radiation. 
 Hence, when the blood is made to circulate more rapidly 
 by irritation of the sciatic, the peripheric parts of the 
 body are so hot that no refrigeration is produced, unless 
 it be brought in contact with the cool medium of the 
 bath. We think that, in this case, the direct stimulation 
 of the vaso-motor nerves of the skin act in concurrence 
 with the reflex central irritations to accelerate the cir- 
 culation of the surface, and thus favor the cooling of 
 the mass of the blood. Also, that the fall of internal 
 temperature observed after excessive irritations of sen- 
 sitive nerves in healthy animals, and which contrasts so 
 remarkably with the rise of temperature determined by 
 their moderate stimulation, depends, not only on varia- 
 tions of the peripheric circulation, but much more upon 
 the direct influence exercised on the nutritive oxydation 
 processes by the central nervous organs. A constant 
 influx of nerve force is as essential to these chemical 
 changes, as is the constant influx of electricity to the 
 chemical changes occurring in certain fluids that may 
 have been just created by the passage of a current. If 
 the action, in these respects, of these organs (spinal cord, 
 medulla, or base of brain) be temporarily abolished by- 
 a shock to the periphery, the heat-making processes are 
 necessarily interrupted. If this violent irritation abol- 
 ishes action, the absence of normal irritation or stimulus 
 to the sensitive nerves of the surface, when the tern- 
 
INFANT DIET. 115 
 
 perature of the medium too nearly approaches its own, 
 should be followed by paresis of this same apparatus ; 
 and, as we have seen, experiment : proves a slackening 
 of nutrition; although, from diminished radiation, 
 there is a slight rise of temperature during exposure 
 to warm air or warm water. 
 
 The muscles constitute one of the principal foci for 
 the production of animal heat; and it is very remark- 
 able that paralysis of the motor nerves, resulting either 
 from lesions of the motor centres in the cord, or from 
 injections of woorara, so notably reduce the tempera- 
 ture. In the first case, the reduction is local, confined 
 to the limb to which the nerves affected are distributed ; 
 in the second, it is general, and may extend four or five 
 degrees (Eiegel.) If the first impression for the modi' 
 fication of temperature is made on the sensitive nerves, 
 the final effect is only obtained when the impression 
 has been transmitted by the motor nerve. Now we 
 know that with paralysis of motor nerves is associated 
 paralysis of secreting glands, which, almost equally with 
 muscles, are under their influence. "We are, therefore, 
 perhaps, justified in supposing that the degree of par- 
 esis of the nerves that follows elevation of external 
 temperature, diminishes the powers of digestion, not 
 only by slackening nutrition, but by directly lowering 
 the secreting powers of digestive glands in the stomach 
 and intestine. 
 
116 INFANT DIET." 
 
 From these considerations we may understand at least 
 some of the reasons why all digestion is more difficult 
 in summer than in winter, and more so in infants than 
 in adults, from the extreme susceptibility of their 
 nervous system, and their comparatively small capacity 
 for regulating the heat-making processes independent 
 of the surrounding medium. Hence the following rules 
 are of more importance for them : — 
 
 Cool the surface by bathing and washing frequently 
 in the course of a hot day. A bath, however, when 
 to be repeated several times a day, must not be of long 
 duration. Let the infant have a drink of plain water 
 now and then, to make up for part of its loss through 
 perspiration ; but no extra food, which will be digested 
 but slowly, and in smaller quantities. At all events, 
 see that the practice of putting infants to the breast, 
 when they are scorched by heat and perspiration, is 
 done away with. Breast-milk is their food as well as 
 beverage under normal circumstances. But in the heat 
 of the summer, while less food is digested and required, 
 more water is wanted. You might try to quench your 
 own thirst by a hearty meal just as well as satisfy with 
 milk the thirst of infants crying for water. With this 
 water ought to be mixed, when the season is very hot, a 
 drachm or two, according to age, and divided into small 
 doses, of brandy or whiskey, in the course of twenty- 
 four hours. 
 
INFANT DIET. 117 
 
 There may arise objections to the latter plan'; and 
 nearly all the criticisms of the first edition of this essay 
 have been directed against this recommendation. It is 
 said that alcohol is an abnormal and unnatural food for 
 babies. But we do not recommend it as food, but as 
 medicine, to be given with the same precautions as any 
 other strong medicine. "While' respecting the convic- 
 tions and appreciating the right to be mistaken of every- 
 body, we claim the administration of alcohol as good 
 practice. In very hot weather the system is no longer J 
 normal, a certain degree of debility, of insufficiency, is 
 perceptible in every function. Therein lies the indicaJ 
 tion for administering a stimulant, partly for its curative, 
 partly for its preservative, effect. Acting on thisprinci 
 pie, you would administer quinine to a person exposed to 
 malaria, who has not yet been taken with an attack 
 of chills and fever, but is pale, easily fatigued, and 
 has a slightly swelled spleen. 
 
 After all this, Mr. President, if I were called upon 
 to write out a few brief and intelligible rules on the 
 feeding of infants in general, and in special behalf of 
 our tenement population, I should think that a few 
 words will be read and remembered better than a long 
 essay; and, although not every indication can be ful- 
 filled, not every taste suited, I hope these few brief 
 rules may do good to the public at large, as they do 
 in my own practice. They would read as follows:— 
 
118 INT ANT DIET. 
 
 I. ABOUT NUESING BABIES. 
 
 Overfeeding does more harm than anything else. 
 Nurse a baby of a month or two every two or three 
 hours. 
 
 Nurse a baby of six months and over, five times in 
 twenty-four hours, and no more. 
 
 When a baby gets thirsty in the meantime, give 
 it a drink of water or barley-water. No suga/r. In 
 hot weather — but in the hottest days only — mix a few 
 drops of whiskey with either water or food, the whiskey 
 not to exceed a teaspoonful in twenty-four hours. 
 
 II. ABOUT FEEDING BABIES. 
 
 Boil a teaspoonful of powdered barley, (grind it in 
 a coffee-grinder,) and a gill of water, with a little salt, 
 for fifteen minutes, strain it, and mix it with half as 
 much boiled milk and a lump of white sugar. Give 
 it lukewarm, through a nursing-bottle. 
 
 Keep bottle and mouthpiece in a bowl of water 
 when not in use. 
 
 Babies of five or six months : half barley-water and 
 half-boiled milk, with salt and white sugar. 
 
 Older babies, more milk in proportion. 
 
 When babies are very costive, use oatmeal instead 
 of barley. Cook and strain. 
 
 When your breast-milk is half enough, change off 
 between breast-milk and food. 
 
INPANT DIET. 119 
 
 In hot summer weather, try the food with a small 
 strip of blue litmus paper. If the blue paper turns 
 red, either make a fresh mess, or add a small pinch 
 of baking-soda to the food. 
 
 Infants of six months may have beef tea or beef 
 soup once a day, by itself, or mixed with the other 
 food. 
 
 Babies of ten or twelve months may have a crust 
 of bread, and a piece of rare beef to suck. 
 
 ~No child under two years ought to eat at your table. 
 Give no candies ; in fact, nothing that is not contained 
 in these rules, without a doctor's order. 
 
 III. ABOUT SUMMER COMPLAINT. 
 
 It comes from overfeeding, and hot and foul air; 
 never from teething. Keep doors and windows open. 
 Wash your children with cold water at least twice a 
 day, and oftener in the very hot season. 
 
 When babies vomit and purge, give nothing to eat 
 or drink for four or six hours, but all the fresh air 
 you can. After that time, you give a few drops of 
 whiskey in a teaspoonful of ice-water every ten min- 
 utes, but not more until the doctor comes. 
 
 When there is vomiting and purging, give no milk. 
 
 Give no laudanum, no paregoric, no soothing syrup, 
 no teas. 
 
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