In my experience there are few American women, especially in the well-to-do classes, who do not look upon the duty of nursing their babies as a pleasant one; but there are many who are completely unable to do so, and a vast number in whom the secretion of milk fails after a few weeks or months of lactation. They must, therefore, through no fault of their own, resort to a wet-nurse or to artificial feeding. Usually they select the last method, with results that vary in direct proportion to the care and intelligence displayed in carrying it out.

There is no artificial food equal to the milk of a robust woman. The fluid, however, secreted from the glands of a feeble or unhealthy mother, though often sufficient in quantity to fill the suckling's stomach and satisfy the cravings of hunger, does not contain enough pabulum to meet the demands of nutrition. In such unfortunate cases, good cows' milk, properly prepared, is a better food than the bad breast milk. More care and trouble, though, are involved in bottle- than in breastfeeding. If the child has been nourished in the natural way - i. e., breast-fed - even for a few weeks, or when the powers of digestion are inherently active, the task is far easier to accomplish. In these cases the stomach and intestinal canal, inactive in foetal life, are trained to their new duties under normal conditions, and so prepared for the digestion of properly selected artificial food. On the contrary, if digestion be naturally feeble, or if the infant must be bottle-fed from the first, great difficulty may be expected, and most skilful handling is necessary.

To insure success in hand-feeding, it must be remembered that an infant is not nourished alone by the food he swallows, but by that portion of it he digests and assimilates. The best diet, therefore, is one so adapted to age and digestive power that everything eaten will be digested and absorbed. But as children differ as much in constitution as in feature, it is impossible to formulate exactly a food that will be applicable to every case, or one that needs no change from month to month of progressing growth. As age and strength increase, there is a corresponding development of the gastro-intestinal functions and a demand for more and stronger food. On the other hand, should the system be accidentally reduced by disease, the digestion, sympathizing in the general debility, temporarily loses its normal activity and assumes that of an earlier age. In such a case more nourishment is certainly needed to build up the failing strength, but it is to be supplied by giving such food as can be completely assimilated, and not by forcing down strong food merely because it is strong; for the latter, when not vomited, passes through the bowels undigested, and the little creature starves to death in the midst of plenty, or dies from the ill effects of the constant presence of fermenting food in the alimentary canal. On these accounts many changes in diet, as to quality and quantity, must be anticipated and made.

Important matters, therefore, to be studied in detail are: a, the selection of a proper substitute for the breast milk; b, the quantity to be given; c, the method of preparation; d, the mode of administration; and, e, the means of preservation.

a. Healthy breast milk must be taken as the type of infant's food, and the nearer an artificial substitute can be made to approach it in chemical composition and physical properties, the more perfect it is.

Normal breast milk has a specific gravity of 1.031. It is a persistently alkaline fluid, having a somewhat animal, usually disagreeable, and very rarely sweetish taste. It is bluish-white in color, thin and watery in consistence, and contains no bacteria.

According to recent analyses, its average composition is:

Fat.............................

Milk sugar (lactose)..............

Proteids........................

Salts...........................

Water..........................

4.00 per cent. 7 .00 per cent. 1.50 per cent. 0.20 per cent. 87.30 per cent.

Some authorities give a higher albuminoid average, namely, 2 per cent.; but, as will be detailed later, the proportion of this ingredient varies greatly, and it is safe to assert that a range from 1.00 to 2.25 per cent, is perfectly normal.

Human milk contains, then, fat, nitrogenous material, sugar, salts and water - all the elements essential to repair tissue waste, to supply new material for growth, and to maintain body heat, or, in other words, to constitute a perfect aliment; and these, too, are so proportioned in the combination as to most easily and completely meet the demands.

It must not be supposed, however, that the elements are uniformly present in the same proportion. On the contrary, the fluid varies both at different periods of lactation and in different individuals.

This fact is the most striking feature of Professor Leeds' experimental work, which shows that the most changeable constituent is the proteids, varying from a maximum of 4.86 per cent, to a minimum of 0.85; the next are the fat and salts, the maximum being about three times the minimum, and the least the sugar. The latter, in fact, varies but little from a standard of about 7 per cent. The function of the proteids is nutritive, that of milk sugar calori-facient; hence, the point seems to be that nature, while allowing a wide range of oscillation in the rapidity of tissue building, carefully provides an available fuel for the constant maintenance of animal heat - the supply of caloric due to cerebral impulses and self-originated locomotion being extremely small in early infancy.

In seeking a substitute for human milk, one naturally turns to the domestic animals for the source of supply. Between the milk of the ass, cow, goat and ewe there is little choice, so far as composition is concerned, although, perhaps, asses' milk resembles that of women a little more closely than the others; nevertheless, cows' milk is usually selected, because, being plentiful, it is easily obtained and cheap.