The maintenance of a dairy herd is considered to be one of the industries essential to the life of a nation. Dairy herds are the greatest single factor in public health and should be carefully conserved. Because the public as a whole does not realize the full significance of this fact, the herds of dairy cattle are being rapidly diminished in this country. Not only is milk a valuable source of food, so much so in fact that if all the milk now produced in this country were utilized to the fullest extent it would supply one fourth of all the food needed by the people in this country, but also a better return for a given amount of fodder can be obtained in the form of milk than in the form of meat. Further, it should not be forgotten, when attempts are being made to increase agricultural production, that a dairy herd is also a valuable source of fertilizer.

Milk is called a "protective food" by Dr. McCul-lom, since it contains all the essential elements for growth. Its average composition is 87 per cent water, 4 per cent fat, 5 per cent sugar, 3.3 per cent protein, and 0.7 per cent ash. It varies, however, as to its fat content, particularly according to the type of cow, a Jersey cow giving the richest milk with often as high as 5 per cent fat, while the milk from a Holstein is the poorest. Most States have fixed the percentage of fat below which the milk must not fall.

The composition of milk is easily seen in the home by noting the changes it undergoes. When left to stand the fat or cream rises to the top. When it grows sour it separates into a solid, the curd, and a yellowish liquid, the whey. If the curd should be heated, it would grow tough and leathery, showing the same characteristics that the white of an egg does when it is heated. Both of these are protein material. The sugar and mineral salts are in solution in the whey and cannot be identified on sight, but together with a soluble protein give to whey, when it is separated from sweet milk, its value as a food for some invalids. This sugar of milk is not as sweet as that obtained from cane and should always be used in modifying cow's milk for infants. It does not ferment as readily and tends to correct putrefaction in the intestines.

An essential industry

Make-up of milk

Of the ash or mineral salts present in milk, calcium is especially important. Milk is the chief source of calcium in all our foods and is especially needed for teeth and bone structure. Since 2 per cent of the total body weight is calcium, 67 grams of calcium should be supplied each day in the ordinary diet. This is found in one and one fourth pints of milk, so that, according to Dr. Sherman, "every family should be using at the rate of at least one third of a quart of milk per man per day to provide for the calcium requirements of that family." The iron content of milk is low, but that can be made up for by the use of eggs and green vegetables.

One of the points in the value of milk as a food does not show in its composition. This is the fact that it has been proven to contain both of those food accessory substances necessary for growth known as "vita-mines." Hence a diet that is lacking in both milk and butter, where the fat-soluble A is found, would be near the danger line for lack of those substances. Dr. Mc-

Cullom asserts that "the greatest factor of safety in the human diet is the regular use of milk." Each adult should use one pint a day, and each child from one and a half pints to one quart a day.

We hear frequently, "It is all very well to talk about the value of milk, but we cannot afford to use it at the present price." When the price of milk went up because of perfectly obvious reasons, such as the high price of fodder and the scarcity of labor, the total amount of money spent for milk was actually less in one city than when the milk was cheaper. And yet milk is a cheap food even at its present price, compared with the cost of other foods and the value received from them. In cutting down the cost of the diet, the last place to cut is milk and the first place to cut is meat. No family of five - that is of two adults and three children - should buy meat until it is using three quarts of milk a day. This is because milk is a food and should not be looked upon just as a beverage to be classed with tea and coffee merely because it happens to be in liquid form. One quart of milk supplies practically as much protein and energy as nine eggs or three quarters of a pound of beef of average composition, and can be bought for less money. When milk is eighteen cents a quart, we get as much food value for our eighteen cents spent for one quart of milk as we should get for:

30 cents put into 3/4 pound of meat at 40 cents a pound; 45 " " " " " " " 60 " " " ; or

45 " " "9 eggs at 60 cents a dozen.

It can be used as an economical substitute for meat or eggs, though it is not as cheap a food as flour or other cereal products.

Value of milk as a food

This does not mean that milk should be used by the glass necessarily, but it can and should be used in cooking. The top of the bottle may be reserved for use on cereal for breakfast or for dessert at dinner, and the rest of the bottle used in cream soups, as chowders, vegetable soups, soups made from dried peas and beans, etc. It can also be used for cream sauces to make a little fish or meat go farther. These can be served in a variety of ways, on toast, in patty shells, in individual ramekins, or made up into souffles or scalloped dishes. Then, too, it may come hard for some people to get used to the idea of a dessert being the meat dish of a meal, but such may be the case if the dessert is largely made of milk as in rice, bread, or cornstarch pudding, or in custard, or even ice-cream. When a milk dish is served either as a soup or a dessert, the meat may be omitted altogether, and the rest of the meal made up of breadstuffs, plenty of vegetables, or salad.

Milk is just as good a food for microscopic animals as it is for larger ones, and as these multiply rapidly in a warm medium and are present in large quantities in dust and dirt of all kinds, cleanliness and cold are imperative in order to have good milk. Milk may be easily a disease-carrier, bringing contamination from the cow, the barn, the utensils used, or the men handling it. The greater precautions that are used to keep it clean, the higher must the price be, of necessity; because these involve a greater expenditure for equipment and for labor. It is safe to say, as a rule, that the more we pay for our milk the cleaner it is.

There are several grades on the market varying in different localities in price and in name. A "certified" milk is a raw milk produced in a single dairy that has been especially inspected and approved by a board of examiners. It is certified to contain not more than a fixed number of bacteria to a cubic inch. Milk of this type is the safest to use for infants and young children.

How to use milk

Care of milk

"Grade A" milk is a good household milk which has usually been pasteurized. Some dealers make the distinction between Grade A and Grade B by having the former come from a comparatively small group of near-by farms, while the latter is an accumulation from many farms often at quite a distance. Milk that has been pasteurized has been heated to 145o F. and kept there for twenty minutes, then cooled rapidly. This is sometimes done with the milk in bulk, then afterwards it is bottled; but it is better to have the milk bottled first and then heated. This process tends to kill the most harmful of the disease bacteria without changing the characteristics of the milk. It must be thoroughly understood, however, that when milk has been so treated, it is not free from the possibility of further contamination. It is still a good culture for whatever micro-organisms may find their way into it.

The process of pasteurization should not be confounded with that of sterilization. This latter is heating the milk to the boiling point three successive times, or holding it at boiling point for thirty minutes. This insures the killing of all bacteria present in the milk, and should always be done if the milk is known to be, or even thought to be, contaminated. It is also wise to sterilize all milk before giving it to a child who runs up a temperature which cannot be accounted for in any other way.

Grades of milk on the market

After a reliable dealer has been chosen and a suitable grade of milk purchased, care should be taken in the home that the milk does not become contaminated there. All milk bottles should be washed before opening, especially around the top even under the cap, and should be placed in the coldest part of the refrigerator. No milk should be allowed to stand in an open pitcher or dish in the room where flies and dust may get at it. Only what is needed at the time should be taken from the bottle; if any is left over, it should not be poured back into the bottle for fear of contaminating the rest. If the paper cap for the bottle has been punctured or thrown away, a tumbler may be inverted over the top of the bottle.

All bottles and other utensils used for milk must be kept clean. They should first be rinsed out in cold water and then washed with soap and scalding water.

Special notice should be taken of the value of skimmed milk. It contains all of the food properties of whole milk except the fat, and so is a very cheap substitute for meat. It can be used in cooking where the loss of fat can be made up by cheaper fats, or it can be made into cottage cheese and used in various ways. If skimmed milk is bought as such, it should be used only in cooking, or else it should be thoroughly sterilized, as it is apt to be more carelessly handled than whole milk.