Vol. 64, No. 24. Whole No. 1727.

Original Articles.

THE FUNCTION OF MATERNAL MILK IN
DEVELOPING THE STOMACH; A FACTOR
HITHERTO OVERLOOKED IN ARTIFICIAL
INFANT FEEDING.*

BY HENRY DWIGHT CHAPIN M.D.
NEW YORK.

FOR a number of years the discussions on artificial infant feeding have centered around the chemical composition of milk, and certain principles thus derived have been enunciated which more recent chemical research has shown to be erroneous. The older teaching that breast milk is alkaline and cow's milk is acid, and consequently alkali should be added to cow's milk, has been shown by Kerley, Gieschen and Myers to be wrong.' It is well known that good results are often obtained by adding alkalis to cow's milk. but the reason that has been given is not supported by the facts. Both human milk and cow's milk are acid to scientific methods of examination. This fact can be easily demonstrated, but an indicator more sensitive than litmus paper must be used (phenolphthalein).

At one time it was taught that success in infant feeding lay in accurate adjustment of the percentages of fat, proteids, carbohydrates, mineral matter and water of milk, plus alkali, to suit the infant's digestion. Now the same teachers are claiming that their treatment of the proteids of cow's milk was not the best and that a new method of adjusting the character of the proteids of cow's milk is proper and scientific. Further study has shown that the proteids of cow's milk are not the same as those of human milk, and not a simple mixture of caseinogen and lact-albumin as has been taught.

The attempt to establish a purely chemical method of feeding has not succeeded, but it has pointed the way toward a clearer understanding of the true principles of artificial feeding.

Fat, proteids, carbohydrates, and mineral matter are generic terms that cover a host of substances. Fat includes fat of meat, butter, lard, and table oils.

Proteids include all lean meat, flesh of birds, fish, eggs, curd of milk, and gluten of cereals.

Carbohydrates include cane sugar, milk sugar, starch of cereals, and potatoes.

Mineral matter includes the entire surface of the earth.

When it is taught that an infant's food should contain certain proportions of fat, proteids, carbohydrates, and mineral matter, a wide range of possibility exists, and what argument can be more logical than that of some manufacturers of prepared foods, who take the words out of the teachers' mouths and make up mixtures that contain the same proportions of fat, proteids, carbohydrates, and mineral matter that were said to be proper, and offer them to the public as representing what some authorities advo

*Read before Pediatric Section of New York Academy of Medicine, November 12, 1903.

$5.00 Per Annum, Single Copies, 10c.

cate? and what can be more illogical than the same authorities decrying all prepared foods as being unscientific? This is not to be construed as advocating the use of prepared infant foods, but is to show that the teachers of scientific infant feeding have not been in an impregnable position as far as such teaching is concerned.

All animals require fat, proteids, carbohydrates, mineral matter, and water, so it is only citing a general principle of nutrition when it is stated that an infant's food should contain them.

Clinical results are greatly in favor of the fat, proteids, and mineral matter derived from milk of some kind as the food for infants. The source of the carbohydrates does not seem to be as important.

It does not strengthen the situation to teach that milk should be used in infant feeding because it contains animal proteid. Any one could add dried blood, egg albumen, or desiccated meat to a food and claim that it met all the requirements of the authorities, as it contained animal proteid.

Young animals need milk because milk supplies forms of proteid that hav sp cial and p.culiar functions that other forms of pr tids do not have. It is to this feature of the proteids of milk that attention is here specially called. To bring out clearly this function, a little sketch of the place of milk in the animal economy will be helpful.

The reproductive process in most animals consists in the development of a single cell into a perfect organism, from food derived from the parent's body. The great differences between animals lie in the manner in which this food is supplied to the germinal cell.

In the case of a hen, all of the food is separated from the mother's body at one time, enclosed in a shell, from which the chick emerges perfectly formed. In some other birds the organs of locomotion are developed after hatching, from the food brought by the parents.

In all forms of animal life the parent either nourishes the young from its own body, or brings it suitable food until it is able to secure food for itself, when weaning takes place.

In animals that suckle their young the greatest variety of methods of supplying nourishment to the germinal cell is seen, but it is not all supplied in one way, in one form or at one time.

Fig. 2. Young Duck-bill as hatched (Owen).

Fig. 3. Mammary outlets of the Duck-bill (Owen).

Figs. 4, 5, 6, 7 show an animal that lays an egg which is hatched in an abdominal pouch and the young is there suckled, the mouth of the young and the outlet of the mammary glands being adapted to each other.

Fig. 7. Mammary gland and foetus of Spiny Ant-eater (Owen).

Figs. 8, 9, 10 show an animal which lays no eggs but gives birth shortly after impregnation to a rudimentary foetus whose mouth grows fast to a teat in the mother's abdominal pouch. Nearly all of this animal's development takes place on this teat. Its increase in weight is from about one-half ounce at birth to eight pounds at weaning. The mother ejects milk into a specially adapted gullet (Fig. 10), which does not connect with the wind-pipe until the young animal is able to suck, when its mouth ceases to be adherent to the teat. As development proceeds, the young thrusts its head out of the pouch (Fig. 8) and nibbles at the food its mother eats. A little later it leaves the pouch for good. Here is the highest development of the mammary function.

Fig. 6. Mammary pocket of Spiny Ant-eater (Wiedersheim).

Fig. 9. Mammary foetus of Kangaroo in pouch

Fig. 11. Young of Opossum adherent to teats. Half life size. Photographed from specimens in the Zoological Collection of Columbia University.

In none of these animals is there any placental connection with the mother. In past ages this method of reproduction predominated over the earth, but animals whose young were nourished in the uterus for a greater or lesser period were more successful in the struggle for existence. Modern mammals are distinguished by the formation of the chorion, which develops into the placenta, through which the nourishment is supplied to the forming organism, mammary development and nutrition. not being so pronounced, although important. At one time mammary nutrition and development of the fœtus were primary. Now they are secondary in nearly all forms of animal life.

Fig. 13. Development of human digestive tract (Allen Thomson and Wiedersheim).

of the human digestive tract from a very simple tube into the specialized organs of the adult.

The

Figs. 14 and 15 show the stomachs of a number of mammals and the digestive tract of a cow. upper part of the stomach of a cow is not developed by milk, but by grass after the true or fourth stomach has been developed by milk.

The digestive tract of the kangaroo at birth (Fig. 9) is very simple and nothing like what it is at weaning, and the stomachs of most mammals at birth are not the same as at weaning; a profound change in the digestive tract takes place during the suckling period.

Colostrum, the first secretion of the mammary

h..

from it, for besides yielding nutriment it possesses properties which serve to cleanse the alimentary tract and properly start the work of digestion... The calf should always get the first milk (colostrum) of the cow, as this is necessary for properly clearing the bowels and starting the digestive functions. . . . It is of the highest importance in horse rearing that the young start in life in full health and vigor, and to this end the foal should very soon after birth take a good draught of the colostrum or first milk of the dam. .

Fig. 15. Digestive tract of cow (Colin & Muller).

"If the young lamb is unable to draw milk within a few minutes after birth, it should have help to secure this first and most important feed. With the first fill of milk from the dam, the new-born lamb becomes comfortable and is usually able thereafter to take care of itself."

It is well known that within a few days after birth normal milk displaces colostrum, which is composed of fat, proteids, carbohydrates, mineral matter and water, as is milk. Milk forms curds in the stomach, which is not the case with colostrum. As these curds are formed from a portion of the proteids of the milk, this is a case where nature quickly alters the character of the proteid of the food to suit a particular purpose.

The digestive secretion of the stomach of an adult is essentially rennet, hydrochloric acid and pepsin.

The function of the stomach is to act as a food reservoir and to break down proteid tissue, so that it can be easily and completely digested in the intestine. Very little complete proteid digestion takes place in the stomach. Before pepsin will act on proteid, a combination of the acid and proteid must take place. In young animals little acid is secreted in the stomach and gastric digestion is not prominent.

One thing about infant feeding that is noticeable is that, as the infant's stomach develops and becomes larger and stronger, longer intervals between feedings become necessary.

It may be argued that the older infant takes more into its stomach; but such an infant's stomach is larger and more vigorous, and should empty as soon as, if not sooner, than at birth.

During the colostrum period there is very little secretion in the stomach, and colostrum is particularly fitted for intestinal digestion. As soon as milk begins to displace the colostrum, there appears an abundant secretion of rennet in a calf's stomach, which acts on the proteid of the milk and changes the milk into a soft solid curd, or junket. Pepsin will not attack this altered proteid or curd of milk, which, being soft, is easily passed into the intestine and there digested. Thus the first function of milk is to fit the stomach for passing soft food into the intestine. The motor function is developed first. Rennet does not act on colostrum and is secreted

in small amount during the colostrum period.

As soon as a little acid is secreted by the stomach, it combines with a portion of the curd to form a definite compound which is readily attacked by pepsin. This compound is denser and tougher than the rennet curds, and unfit for intestinal digestion. The stomach has now something to do besides emptying itself, and the food remains longer in the stomach to give the pepsin time to act. As the secretion of acid increases, more of the curd combines with the acid, and there is more work for pepsin. In this way, as fast as the gastric glands develop they find work awaiting them. Thus it is that the stomach is called into action, and longer intervals between feedings become necessary. If there was not some such provision, mother's milk ought to change in character as the digestive function becomes stronger to meet the stronger digestive juices, or atrophy of the digestive glands would ensue. As it is, mother's milk adapts itself to a weak infant or to a strong one. If the gastric secretion is vigorous, the milk becomes more solid and stays longer in the stomach; if weak, the milk forms a softer clot which easily passes into the intestine in a condition to be rapidly digested there. M ther's milk and the secretions of the infant's gastrointestinal tract automatically adapt themselves to each other. If mother's milk itself changed in character according to the age of the infant, it would never agree with a puny, backward infant; and if milk did not turn into a solid, but remained a fluid, the stomach would not be prepared for solid food at weaning, for there would be nothing to properly develop the motor and glandular functions.

It has been seen (Figs. 2, 3. 7. 10 and 11) that, anatomically, young animals and mothers are perfectly adapted to each other; they are also func tionally ad ipt d to each other.

In the change from colostrum to milk, the mother alters the character of the proteid supplied, and the infant's digestive secretions change at the same time for a specific purpose. The proteid of mother's milk adapts itself to the young animal's digestive secretions.

A glance at the different stomachs (Fig. 14) will suggest that one form of proteid would not fit them all unless their digestive juices had different effects on it. It is a familiar fact that the milks of different species form different kinds of curds under the action of the same rennet and acid, and universal experience has shown that the proteid or curd of the milk of the lower animals does not perfectly fit a baby's stomach. The only conclusion possible is that the proteids of different milks are not the same from a functional standpoint, no matter how nearly alike they may be in ultimate chemical composition.

In artificial feeding it is essential to supply as much fat and carbohydrates as is found in breast milk to serve as fuel for the body, and as much proteid and mineral matter as is found in breast milk to build up a strong body, or anæmia, rickets, and general malnutrition will follow. It is also essential that a portion of the proteid shall be of a form that will develop the stomach, as the lack of such food will profoundly affect the general nutrition.'

Fresh cow's milk is the only available source of such a form of proteid, and for this reason fresh milk should be the backbone of the baby's food. However, the proteid of cow's milk does not fit a baby's stomach and must be altered in some way to make it fit. In the cow, digestion is principally gastric, and food slowly leaves the stomach. Cow's milk curds in such large masses that it cannot readily leave the stomach. In man, finely divided food that readily leaves the stomach is natural, and human milk does not form solid curds. but flakes." Altera

tion of the character of cow's milk may be brought about by a number of methods, and one method may succeed when another fails.

Sterilizing, pasteurizing, or heating cow's milk alters it chemically so that rennet will not act upon it readily. This fact is familiar to every cook, as on the packages of rennet sold for making junket for desserts will be found: "Use pure sweet milk, heat carefully until just lukewarm, remove at once from the fire, as you may overheat it, as milk or cream that has been boiled, sterilized, condensed or evaporated cannot be used." Heating milk also destroys bacteria that produce acid, an excess of which would combine with the rennet curds and form a dense mass far beyond the capacity of the infant's peptic digestion. Investigation has shown that pasteurized or sterilized milk as fed to infants is not at all free from bacteria, so a part of the benefit of heating milk lies in altering the character of the milk and preventing the formation of acid.

The addition of alkalis to cow's milk retards the action of rennet or neutralizes the acid of the stomach, and thus throws the milk into the intestine more rapidly and in a softer condition.

The dilution of cow's milk with plain gruels holds the curds apart and allows more rapid emptying of the stomach.

Diluting cow's milk with dextrinized gruels supplies the mechanical effect of plain gruels, puts a modicum of starch in the infant's stomach, adds a natural promoter of gastric secretion to the food and supplies some readily absorbable food which is found in all milks, but which is reduced in quantity in diluted cow's milk.

function is not normal and will possibly add a large quantity of alkali to the milk to cause it to rapidly leave the stomach as a fluid, or he may decide that a nearly soluble food is required, and peptonize the milk or stop milk entirely and feed dextrinized gruel getting back to milk gradually. Reducing the quantity of proteid of cow's milk to.25 or .50 per cent., except temporarily to correct functional disturb. ances, is not justified, if another form of nucleoalbumin, with more or less cow's milk, can be digested. Indigestion is being treated by partial starvation where such low proteids are supplied. It may be found that the infant is taking a soluble food which requires little digestive effort, and is not doing well. A change to milk causing immediate improvement suggests that the stomach was craving work which the curding of the milk supplies.

A careful study of the experience of all pediatricians will show that success has not followed rigid adherence to any rule of feeding, but along adaptation of the food to the state of the infant's digestion, the most radical changes in the character of the food sometimes giving good results. In these instances the food was inelastic in its character, and only a portion of the proper functional development was being produced. The radical change of food produced a development that was needed.

Normal maternal milk supplies the necessary quantities of fat, proteids, carbohydrates, etc., for proper structural development and maintenance of the vital processes, in forms that automatically adapt themselves so as to develop the digestive functions of the growing animal.

It is easy to make up a food that will contain the same quantities of fat, proteids, carbohydrates, etc., as maternal milk, but experience and study only will enable the infant-feeder to do what nature does automatically-adapt the food to the conditions actually present and ensure proper functional development. Biology must be considered fully as much as chemistry in the study of artificial infant feeding. REFERENCES.

1. "Some Comparative Examinations of Breast Milk and Cow's Milk and the Effect of the Addition of Alkalis and Other Antacids to Cow's Milk," MEDICAL RECORD, August 8, 1903. Chemical Pathology," C. H. Herter. 2. "Feeds and Feeding," W. A. Henry. "Food and Dietetics," Robt. Hutchinson.

3. "Fermentation," J. Reynolds Green. "Textbook of Physiological Chemistry," Hammersten. "Physiologic and Pathologic Chemistry," Bunge, Second Edition.

4. Bulletin 215, New York Agricultural Experiment Station.

5. "Animal Life," David Starr Jordan and Vernon L. Kellogg. "Textbook of Zoology," Parker & Haswell. Comparative Anatomy and Physiology of Vertebrates," Owen. "Physiology of the Domestic Animals," R. Meade Smith. "The Theory and Practice of Infant Feeding," Henry Dwight Chapin, M.D.

51 WEST FIFTY-FIRST STREET.

Victims of the Jungle. It is noted in The Times of London that in 1901 more human beings were killed by wild animals than in any year since 1875 except one, and reached a total of 3,651, while last year it was 2,836; and the number of deaths from snake bite was 23,166. Tigers killed 1,046 persons, of whom 544 perished in Bengal, 65 being in a single district. This was due to the depredations of a man-eater, for the destruction of which a special reward was offered without avail. In another district, where 43 persons were killed, most of them fell victims also to a man-eater. Wolves slew 377 persons. Eleven thousand one hundred and thirty deaths took place in Bengal alone from snake-bite, 3,258 of these being in the Patna division, while 5,110 deaths took place in the United Provinces; 80,796 cattle (an increase on the previous year) were killed by wild animals last year, and 9,019 by snakes. Tigers killed 30,555 of these, leopards 38,211, and wolves and hyenas most of the remainder.