Liebig's Foods.
| Mellin's. | Hawley's. | Horlick's. | Keasbey and Mattison's. | Savory and Moore's. | Baby Sup No. 1. | Baby Sup No. 2. | |
| Water | 5.00 | 6.60 | 3.39 | 27.95 | 8.34 | 5.54 | 11.48 |
| Fat | 0.15 | 0.61 | 0.08 | None. | 0.40 | 1.28 | 0.62 |
| Grape-sugar | 44.69 | 40.57 | 34.99 | 36.75 | 20.41 | 2.20 | 2.44 |
| Cane-sugar | 3.51 | 3.44 | 12.45 | 7.58 | 9.08 | 11.70 | 2.48 |
| Starch | None. | 10.97 | None. | None. | 36.36 | 61.99 | 51.95 |
| Soluble carbohydrates | 85.44 | 76.54 | 87.20 | 71.50 | 44.83 | 14.35 | 22.79 |
| Albuminoids | 5.95 | 5.38 | 6.71 | None. | 9.63 | 9.75 | 7.92 |
| Gum, cellulose, etc. | ... | ... | ... | ... | 0.44 | 7.09 | 5.24 |
| Ash | 1.89 | 1.50 | 1.28 | 0.93 | 0.89 | Undeterm'd. | 1.59 |
Milk Foods.
| Nestle's. | Anglo-Swiss. | Gerber's. | American-Swiss | |
| Water | 4.72 | 6.54 | 6.78 | 5.68 |
| Fat | 1.91 | 2.72 | 2.21 | 6.81 |
| Grape-sugar and Milk-sugar | 6.92 | 23.29 | 6.06 | 5.78 |
| Cane-sugar | 32.93 | 21.40 | 30.50 | 36.43 |
| Starch | 40.10 | 34.55 | 38.48 | 30.85 |
| Soluble carbohydrates | 44.88 | 46.43 | 44.76 | 45.35 |
| Albuminoids | 8.23 | 10.26 | 9.56 | 10.54 |
| Ash | 1.59 | 1.20 | 1.21 | 1.21 |
It is seen by examination of the analyses of the above foods that all except such as consist largely or wholly of cow's milk differ widely from human milk in their composition, and although some of them—as the Liebig preparations, in which starch is converted into glucose by the action of the diastase of malt—may aid in the nutrition and be useful as adjuncts to milk, physicians of experience and close observation will, I think, agree with the German conference that when breast-milk fails or is insufficient our main reliance for the successful nutrition of the infant must be on animal milk. Nestle's Food, which consists of wheat flour, the yelk of egg, condensed milk, and sugar, and which has been so largely used in this country and in Europe, is probably beneficial mainly from the large amount of Swiss condensed milk which it contains.
Although the preference is to be given to animal milk over any other kind of food as a substitute for human milk, yet even when obtained fresh and from the best dairies and properly diluted it is very apt to disagree with infants under the age of one year, producing indigestion and diarrhoea. The close resemblance in chemical character of cow's, ass's, and goat's milk to human milk would lead us to expect that either would be a good substitute for the latter. The fact that the milk of these animals is apt to cause indigestion and intestinal catarrh, especially in the hot months, when the digestive function of the infant is enfeebled from the heat, must be due to the quality rather than quantity of its constituents. The difference in quality of the casein of human and animal milk is well known, since that of human milk coagulates in the stomach in flakes, and that of animal milk in firm and large masses. The German conference saw at once the importance of the problem which confronted them—i.e. how to modify cow's milk so that it bears the closest possible resemblance to human milk. They even discussed the difference of the milk of different breeds of cows, and the proper feeding and care of cows, but the most important suggestion made—and one which has already produced good results in this country and in Europe, and promises to be instrumental in saving the lives of many infants who by the old method of feeding would inevitably perish—was made by Pfeiffer of Wiesbaden. I allude to the peptonizing of milk. The pancreatic secretion digests milk that is rendered alkaline at a temperature between 100° and 150° F. Milk thus treated becomes in from twenty minutes to one hour thinner, resembling human milk in appearance, and if the peptonizing be continued beyond a certain point, and is more complete, its taste is decidedly bitter. The process should be watched and the peptonizing suspended as soon as the bitterness becomes appreciable, for, although more advanced peptonizing so changes the milk that it is more easily digested by the infant than when the peptonizing is partial, yet the bitterness which is imparted to it renders it very disagreeable as a dietetic preparation. Milk thus prepared closely resembles human milk in appearance, and its casein is so digested that it is either not precipitated by acids or is precipitated, like that of human milk, in flakes. By this process a digested or an easily-digested casein is produced, instead of the casein of ordinary cow's milk, which produces large and firm masses in the stomach—masses that the digestive ferments penetrate with such difficulty that they cause indigestion, and occur in the stools in coagula of greater or less size. Pfeiffer pointed out that when peptonized milk is employed "the feces showed absolutely no trace of the white cheesiness." Milk thus prepared quickly spoils, and it is necessary to peptonize it in small quantity and often during the twenty-four hours.
In New York City during the last year peptonized milk has been employed largely as recommended by Pfeiffer, and with such results as to encourage its further use. It is now used in the New York Infant Asylum and New York Foundling Asylum. Five grains of extractum pancreatis (Fairchild & Co.'s) and ten grains of sodium bicarbonate are added to one gill of warm water. This is mixed with one pint of warm milk, and the mixture, in some convenient vessel, is placed in water kept at a temperature of 100° F. for one hour, when it is placed upon ice to prevent further digestion. It should be tasted frequently during the peptonizing process, and if the least bitterness be observed the process should be suspended before the expiration of the hour. With some specimens of milk, especially at a temperature of 115° to 120°, a half hour or even less is sufficient. This artificial digestion is arrested either by boiling the peptonized milk, which destroys the ferment, or by reducing its temperature to near the freezing-point, which renders it latent and inactive, but does not destroy it. I need not add that placing the peptonized milk on ice is preferable to boiling it, since we wish the ferment to continue to act in the stomach of the infant. In the present state of our knowledge of infant feeding, therefore, we can recommend no better substitute for human milk than peptonized cow's milk.
Leeds recommended the following formula for peptonizing milk in his very instructive remarks made before the New York County Medical Association, July 16, 1884. In order that no mistake might be made, I wrote to him for his formula, which he kindly sent me. The following is an extract from his letter: "The formula which I ventured to suggest for the preparation of humanized cow's milk was as follows: 1 gill of cow's milk, fresh and unskimmed; 1 gill of water; 2 tablespoonfuls of rich cream; 200 grains of milk-sugar; 1½ grains of extractum pancreatis; 4 grains of sodium bicarbonate. Put this in a nursing-bottle; place the bottle in water made so warm that the whole hand cannot be held in it without pain longer than one minute. Keep the milk at this temperature for exactly twenty minutes. The milk should be prepared just before using."
The object is of course to provide from cow's milk a food which will be the nearest possible approximation to healthy human milk; and this appears to be achieved by the peptonizing process. Certainly, what physicians have long been desiring—namely, some mode of preparing cow's milk so that its casein will coagulate in flakes like that of human milk—has been obtained by peptonizing.