(1) By mixing into the milk some substance which shall separate the particles of albumen from each other, and so cause it to form into smaller masses.

(2) By partial predigestion.

To accomplish the first, it is necessary to use some diluting substance of a harmless nature; if it be nutritious, so much the better. For this, Mellin's food, barley-water, veal broth, lime-water, and gelatin are recommended.

Mellin's food is a partially predigested grain, in such a condition that it can be assimilated by the infant; barley-water is valuable for its potash salts, in which cow's milk is deficient, and which the growing babe needs; veal broth is rich in lime; and lime-water neutralizes the acid of the gastric juice, so that milk is not acted upon so strongly, and consequently forms into a lighter curd.

1 The following mineral substances occur in both cow's and woman's milk: potassa, soda, lime, magnesia, iron, phosphoric acid, sulphuric acid, and chlorin.

The second method is that of partial predigestion, and is accomplished by the use of peptonizing agents, among which Fairchild's peptogenic milk-powder is good (directions for its use will be given later). On account of the expense of these preparations it is not probable that they will come into general use, except in cases of sickness.

It is therefore evident that dependence must be placed almost entirely upon attenuants to render the casein of cow's milk more easily digestible. Probably for this Mellin's food is as good, if not better, than any other of the recommended preparations. It is not injurious, is nutritious in itself, and is a good diluting agent, causing milk to form into looser curds than it would otherwise do, and it contains sufficient sugar to require no further addition of this substance.

Now arises the question whether milk shall be sterilized for infants' feeding. The weight of evidence seems to be as follows: if it is possible to see the conditions under which the cows live, and to know that they are unquestionably good, that the animals are in perfect health, that the milk is drawn from cleansed udders into cleansed vessels by clean hands, kept in a cool place, and used fresh, then it is probably wise not to sterilize it. All milk otherwise obtained should be made sterile before using, and as soon as possible after milking. Looking to the standard - human milk - there are no organisms in it. That alone is sufficient reason why cow's milk should be freed from them.1

Again, most bottle-fed children do well during the cold weather of autumn and winter; in summer the mortality is very great among them, especially in the poorer districts of large cities. It is well known that the chances for life with children nourished by mother's milk are greater than with those artificially fed. Why should this be ? There is no doubt that it is owing to the presence in cow's milk of extraneous substances, the products of bacterial growth - products which are often absolute poisons; and it is highly probable that cholera infantum, in a vast majority of cases, may be traced to the action of such poisons.

Under favorable conditions of temperature, such as prevail in the warm months of summer and early autumn, micro-organisms grow with almost incomprehensible rapidity in any substance which is suitable food for them. Milk is such a substance; and, as bacteria multiply with wonderful rapidity, millions forming in a few hours in every thimbleful,2 it is perfectly evident that they must produce something. This something may or may not be of a harmful nature, depending upon what species of organism produces it. I have no evidence at hand to show what is the nature of the product of any one organism which finds a home in milk; but there are instances on record where the nature of the product of certain bacteria is known: for example, the diphtheria bacillus. This little rod, growing upon the outside of the tonsils in the human throat, produces a most virulent poison, which, taken up by the circulation, pervades the whole body, and often so enfeebles its functions as to destroy it.1

1 It is worthy of notice, in this connection, that children have been known to be made ill by drinking water which has stood for a length of time - such water containing great numbers of bacteria, but none of the so-called disease-producing organisms. The same water, when boiled, produced no ill effects.

2 Stated by Sedgwick.

Reasoning from analogy, it is not impossible to suppose that other organisms may produce substances of a similar character, poisonous in their effects, and which, when taken into the alimentary canal, may produce very grave digestive disorders.2

Further, bacteria, by their multiplication, use some of the constituents of milk for their food, thus changing its composition. It is very important to prevent this growth, or, in case it has begun, to check it before it has rendered the milk unwholesome food. Hence the necessity of sterilizing immediately all milk which is not received directly from the cow. Besides, cows are often infected with tuberculosis, foot-and-mouth disease, splenic fever, pneumonia, and other dangerous disorders. Their milk may be a direct cause of infection. When it is sterilized there is less danger from it; but even then it is not, of course, a wholesome food, because of the poisons which may be produced in the animal during the progress of the disease, and because a sick and weakened cow cannot give wholesome milk.3

In many cities, through the influence of children's hospitals and sanitariums, the knowledge and methods i Welsh.

2 Since writing the above I have learned that Prof. Vaughan has isolated a poisonous matter - the product of the growth of certain organisms which multiply readily in milk - which caused active vomiting, purging, collapse, and death when injected into the lower animals.

3 In England and America many cases of scarlatina, typhoid fever, and diphtheria have been traced to the milk supply. But there is no satisfactory evidence that those diseases were transmitted from the cow; more probably the milk, which is an especially good nutritive medium for bacteria, became infected after leaving the cow. In October, 1891, an epidemic of diphtheria prevailed in Melrose, Mass. Thirty-three cases were reported. On investigation it was found that every case of sterilizing milk for infants' food are gradually-spreading.