Cow's milk, like mother's milk, is made up of solids and water. In a previous chapter we learned that in one-hundred parts of mother's milk, eighty-seven parts were water and thirteen parts were solid. These thirteen parts of solids consist of sugar, proteins, and salts; this is likewise the case with cow's milk, except that in the case of the cow's milk, the sugar is decreased while the proteins are increased as will be noted by the accompanying comparative analysis:

Mother's milk is absolutely sterile, that is, free from the presence of germs; on the other hand, cow's milk is anything but sterile—the moment it leaves the udder it begins to accumulate numerous bacteria, all of which multiply very rapidly. Cow's milk is generally twenty-four to forty-eight hours old before it can possibly reach the baby. It is just as important to keep in mind these facts of milk contamination—dirt, filth, flies, and bacteria—as it is to plan for the modification of cow's milk for the purpose of making it more nearly resemble mother's milk. While mother's milk has about the same percentage of fat as cow's milk, it is almost twice as rich in sugar, and has only one-fourth to one-third as much protein. This protein is vastly different from that found in cow's milk, which you recall has a tough curd, as seen in cottage cheese. While mother's milk contains a small amount of casein similar to that found in the cheese of the cow's milk, the principal protein constituent is of another kind (lactalbumin), and is much more easy of digestion than the casein of cow's milk.

This is a most important point to remember, because the baby's stomach is not at first adapted to the digestion of the heavier and tougher protein curds of cow's milk. It requires time to accustom the infant stomach to perform this heavier work of digestion. There are a number of factors which must be borne in mind in the modification of milk, whether it be cow's milk, or goat's milk (for many European physicians use goat's milk entirely in the artificial feeding of infants): namely, the cleanliness of the milk, the acidity of milk, the difference in the curd, the percentage of sugar, and the presence of bacteria.

SUGAR

In the modification of cow's milk, sugar must be added to make up for the sugar which is decreased when the water was added to reduce the protein. There are several sorts of sugar used in the modification of milk. These sugars are not added to sweeten the milk alone, but to furnish a very important element needed for the growth of the baby. Sugar is the one element which the infant requires in the largest amount.

Milk sugar is probably most universally used in the modification of milk, but a good grade of milk sugar is somewhat expensive, costing from thirty to sixty cents a pound, and this places it beyond the reach of many mothers. It is added to the food mixtures in the proportion of one ounce to every twenty ounces of food. Cane sugar (table sugar) may also be used, but it must be clean and of good quality. It is used in rather less quantity than that of milk sugar, usually from one-half to one-third of an ounce by measure to each twenty ounces of food. Dextri-maltose (malt sugar) is very easy of digestion and may be used in the modification of milk. Maltose seems to help the children to gain more rapidly in weight than when only milk or cane sugar is used. It is also exceedingly useful in constipation, as its action is more laxative than any of the other sugars; but it should not be given to children who vomit habitually or have loose stools.

ACIDITY

Like mother's milk, the cow's milk is neutral as it comes from the udder; but, on standing, it quickly changes, soon becoming slightly acid, as shown by testing with blue litmus paper. In fact, what is known as ordinarily fresh milk, if subjected to the litmus paper test, always gives an acid reaction. This acidity is neutralized by adding lime water to the formula in the proportion of one ounce to each twenty-ounce mixture. Ordinary baking soda is sometimes prescribed by physicians in place of the lime water. In the event of obstinate constipation, milk of magnesia is sometimes added to the day's feedings.

CREAM

There may be procured in any large city an instrument called the cream gauge, which registers approximately (not accurately) the richness of milk. Some milk, even though rich, parts with its cream very slowly; while some poor milk allows nearly all the cream quickly to rise to the surface. We know of no way for the mother to determine the amount of cream (without the cream gauge) except by the color and richness of the milk. In cities it is very convenient to send a specimen of the milk to the laboratories to be examined by experts, who will gladly render a report to both physician and mother.

The lactometer is a little instrument used to estimate the specific gravity of milk. An ordinary urinometer such as used by physicians in estimating the specific gravity of urine may also be used. The specific gravity of cow's milk should not register below 1028 or above 1033.

HERD MILK

Milk from a single cow is not to be desired for baby's food because of its liability to vary from day to day, not to mention the danger of the cow's becoming sick. Authorities have agreed that herd milk of Holstein or ordinary grade cows is best for infant feeding. This mixed-herd milk contains just about the proper percentage of fat; whereas, if Jersey milk must be used, some of the cream should be taken away. Our milk should come from healthy cows which have been tested for tuberculosis at least every three months.

Annatto is sometimes added to milk to increase its richness of color. To test for annatto proceed as follows: To a couple of tablespoons of milk add a pinch of ordinary baking soda. Insert one-half of a strip of filter paper in the milk and allow it to remain over night. Annatto will give a distinct orange tint to the paper. The commonly used milk preservatives are boracic acid, salicylic acid, and formaldehyde, any of which may be readily detected by your health officials.

SANITARY DAIRIES

In close proximity to most large cities there is usually to be found one or more sanitary dairies. It is a joy indeed to visit a farm of this kind with its airy stables and concrete floors, which are washed with water coming from a hose. The drainage is perfect—all filth is immediately carried off (Fig. 11). The cows are known to be free from tuberculosis, actinomycosis (lumpy jaw), and foot and mouth disease. The milkmen on this farm wear washable clothes at the milking time, and their hands are painstakingly cleansed just before the milking hour. Previous to the milking the cattle have been curried outside the milking room and their udders have received a careful washing. The milkman grasps the teat with clean hands, while the milk is allowed to flow through several thicknesses of sterilized gauze into the sanitary milking pail. This milk is at once poured into sterile bottles, is quickly cooled and shipped in ice to the substations where the delivery wagon is waiting. In the ideal delivery wagon there are shallow vats of ice in which the bottles are placed, thus permitting the milk to reach the baby's home having all the while been kept at a temperature just above the freezing point.

And why all this trouble? Why all this worry over temperature and cleanliness? Babies were not so cared for in the days of our grandmothers. The old-fashioned way of milking the cows with dirty clothes and soiled hands, while cattle were more or less covered with manure, with their tails switching millions of manure germs into the milking pail, produced a milk laden not only with manure germs—the one great cause of infantile diarrhea—but also swarming with numerous other mischief making microbes. Even tuberculosis, that much dreaded disease germ of early infancy, may come from the dairy hands as well as from infected cows.

There used to be many dairymen like the old farmer who, when interrogated by the health commissioner concerning the cleanliness of his milk, laughed as he reached down into the bottom of a pail of yellow milk and grabbing up a handful of manure and straw, said: "That's what makes the youngsters grow." But it does not make them grow; it often causes them to die, and even if they do live, they live in spite of such contaminated food, for the germ which is always found in the colon of the cow (coli communis), probably kills more babies every year than any other single thing.

It is possible to reduce the growth of these germs by keeping the milk at a very low temperature from the time it leaves the cow until the moment it gets to the home refrigerator. Those which survive this process of refrigeration may be quickly rendered harmless by pasteurizing or sterilizing at the time of preparing baby's food.

In the absence of the modern sanitary dairy, we would suggest that the milk supply be improved by giving attention to the following:

The cattle should be tested for tuberculosis every three months. The walls of the cowhouse should be whitewashed three times a year. The manure should be stored outside the barn. The floor of the cowhouse should be sprinkled and swept each day. The cattle should be kept clean—curried each day, and rubbed off with a damp cloth before milking. The udders should be washed before each milking. The milker can wear a clean white gown or linen duster which should be washed every two days, while his hands should be washed just before the milking. The milking pail should be of the covered sanitary order. The barn should be screened.

CERTIFIED MILK

Immediately after leaving the cow, the milk should be cooled to at least 45 F. It should at once be put into bottles that have been previously sterilized and then be tightly covered, and should be kept in ice water until ready for consumption. No matter how carefully the milk is handled, it is infected with many bacteria, but if it is quickly cooled, the increase of the bacteria is greatly retarded. Under no circumstances buy milk from a grocery store out of a large can. Go to your health officer and encourage him in his campaign for sanitary dairies and certified milk.

Such milk as we have described under the head of sanitary dairies, when it has been tested by the board of health and has received the approval of the medical profession, is known as "certified milk;" and, although the price is usually fifteen to twenty cents a quart, when compared with the cost of baby's illness it will prove to be cheaper than the dirty milk which sickens and kills the little folks.

There is no doubt that the increased use of "certified milk" has been a great factor in the reduction of deaths from infant diarrhea in recent years.

BOILING THE MILK

When certified milk cannot be had, it is absolutely dangerous to give raw, unboiled, or unpasteurized milk to the baby, particularly in warm weather; for the countless millions of manure germs found in each teaspoon of ordinary milk not only disturbs the baby's digestion, but actually makes him sick, causing colic, diarrhea, and cholera infantum. The only way this milk can be rendered safe is by cooking it—actually killing the bacteria. This process of boiling, however, does not make good milk out of bad milk nor clean milk out of that which is dirty, it simply renders the milk less dangerous.

There are two methods of killing bacteria—sterilization and pasteurization. By sterilization is meant the process of rendering the milk germ free by heating, by boiling. Many of the germs found in milk are comparatively harmless, merely causing the souring of milk; but other microbes are occasionally present which cause serious diseases, such as measles, typhoid and scarlet fever, diphtheria, tuberculosis, and diarrhea. It is always necessary to heat the milk before using in warm weather, and during the winter it is also important when infectious or contagious diseases are prevalent.

Milk should be sterilized when intended for use on a long journey, and may be eaten as late as two or three days afterward.

To sterilize milk, place it in a well-protected kettle and allow to boil for one hour and then rapidly cool. This process renders it more constipating, and for some children many of its nutritive properties seem to be destroyed, as scurvy is often the result of its prolonged use. When a child must subsist upon boiled milk for a long period, he should be given the juice of an orange each day. Children are not usually strong and normal when fed upon milk of this character for indefinite periods. All living bacteria (except the spores or eggs) may be destroyed by boiling milk for one or two minutes.

PASTEURIZATION

When baby is to use the milk within twenty-four hours, "pasteurization" is better than boiling as a method of destroying microbes.

There are many pasteurizers on the market which may be depended upon, among which are the Walker-Gordon Pasteurizer, and Freeman's Pasteurizer; but in the absence of either of these pasteurization may be successfully accomplished by the following method:

On the bottom of a large kettle filled with cold water, place an ordinary flatiron stand upon which is put a folded towel. On this place the bottle of milk as it comes from the dairyman, with the cap of the bottle loosened. The cold water in the kettle should come up to within an inch of the top of the bottle of milk. Heat this water quickly up to just the boiling point—until you see the bubbles beginning to rise to the top. The gas is then turned down or the kettle is placed on the back of the range and held at this near-boiling point for thirty minutes, after which it is taken to the sink and cold water is turned into the water in the kettle, until the bottle of milk is thoroughly cooled. It is now ready to be made up into the modified food for baby.

Never let pasteurized milk stand in the room, nor put it near the ice when warm. It must be cooled rapidly, as described above; that is, within fifteen or twenty minutes.

The "spores" of the milk are not killed by pasteurization and they hatch out rapidly unless the milk is kept very cold, and, as already stated, it should be used within twenty-four hours after pasteurization.

THE CARE OF BOTTLED MILK

The certified milk or the ordinary milk that has been delivered to your home and is to be used without pasteurization or sterilization, should receive the following care:

1. It should be placed at once in a portion of the ice box that is not used to store such foods as radishes, cabbage, meats or any other open dishes of food whose odors would quickly be absorbed by the milk. The milk should never be left standing on the doorsteps in the sun, for many reasons: the sun heats the milk, encourages the growth of bacteria, and a passing cat or dog, whose mouth often contains the germs of scarlet fever, tonsilitis, and diphtheria, should it be hungry, laps the tops of the bottles, particularly in the winter when the cream has frozen and is bulging over the edge.

2. It should never be kept in the warm kitchen, as when visiting her sick baby we discovered one young mother doing. In answer to my question, she explained; "Doctor, we do not take ice in the winter time, everything is ice outdoors, so I just set the bottle outside the window bringing it in whenever I need to give the baby some food. I forget to put it out sometimes, but really now, does it matter?" It really matters much, for you see, reader, the milk is first freezing then thawing and it is rendered entirely unfit for the baby.

3. Milk should be kept covered and protected from dust and flies; it should be kept in glass jars which have been sterilized by boiling before being filled, and then placed in the refrigerator. If the milk is sour, or if there is any sediment in the bottle, it is unfit for baby's use.