Unfortunately, there are many sources from which milk, under the present conditions of supply, is contaminated. The cow is not kept scrupulously clean. The milker's hands are dirty, and the farm dairy is rarely beyond reproach. In the town dairy, again, are many sources of contamination, whilst the distribution of milk to the customers leaves much to be desired. The milk is thus not to be trusted as a food for an infant's consumption. The only way to ensure freedom from germs would be to boil everything that comes into contact with the milk.
Germs inevitably find their way into the milk in its transit from the farm to the nursery. Once germs enter, they multiply freely in the medium of milk, and cause many illnesses and deaths, even in the best regulated nurseries.
It was M. Pasteur who first brought forward the theory that by heating milk until the germs and their spores were destroyed, and then preventing the entrance of further germs into the milk, it would " keep" indefinitely. Before this, milk was boiled in order to sterilise it, but sterilisation destroys some of its nourishing properties, and also makes it less digestible. Pasteurisation, on the other hand, means raising the milk to the temperature of 1600 F., which temperature does not alter the composition of the milk or affect its smell or taste. It does, however, destroy the germs, the microbes which cause tuberculosis, typhoid fever, diphtheria, and other diseases. A simple apparatus can be bought for pasteurising milk, but there are other ways of doing this at home, without any apparatus.
1. The milk may be put in a bottle, which should be plugged by a piece of cotton-wool, previously passed through a gas flame to ignite it, and the flame blown out. Put the bottle of milk into a clean enamel-lined saucepan of cold water. The temperature of the water should be raised to 1600 F., tested by a thermometer kept for the purpose. Then put the saucepan at the side of the fire, covering saucepan and bottle with a piece of flannel for half an hour. The bottle should be taken out and its contents allowed to cool, but it must not be opened until required for baby's use.
This method must only be used when the milk is fresh, and procured from a reliable source. It may be relied upon by people who have their own cow, which has been tested by the veterinary surgeon and passed as free from tubercular disease.
2. Town milk, however, cannot with any safety be relied upon as a clean food for infants, and the following method is safest to protect a child from infection by completely destroying the germs and their spores in the milk.
The method is more accurately called sterilisation of milk, because the milk is raised to a much higher temperature and " sterilised " - that is, all microbic life is killed. It may be done in the same way as for pasteurisation, except that the water in the saucepan should be raised to boiling point (2120 F.). Personally, I have always found the following method answer well, and the milk, when sterilised, can be put directly into one of the two jugs already mentioned for holding baby's milk by day or night.
Procure a double enamel saucepan. Put the milk into the upper saucepan and fill the lower with cold water. Cover the upper saucepan with a lid to protect from dust. Put the saucepan on the fire, and allow the water to come to boiling point, and keep it there for twenty minutes. Then pour the milk into a clean jug. One drawback to this method is that a scum is caused on the milk, due to the coagulation of the albumen, and the anti-scorbutic properties are destroyed, so that the baby, unless care is taken, is more liable to scurvy, a disease due to deficient quality of the blood, when the baby is fat, puffy and anaemic. If, however, proper hygienic care is taken of the child, there need be no fear of its contracting scurvy, and the mother's mind can rest much more assured that summer diarrhoea, tuberculosis, and other infantile ailments will be prevented. We shall see later, as the baby grows, that a little raw meat juice will be given to him, which has very great anti-scorbutic properties, and so prevents anaemia and scurvy.
After the milk has been pasteurised or sterilised, it is placed in the jug, and diluted with the quantity of water or barley-water ordered by the doctor. The milk should be measured as it is added to the jug, and the proper amount laid aside for the day or night according to the child's age. For example, during the first month baby gets half an ounce of milk mixed with half an ounce of water, or barley-water, every two hours. That means that he gets five ounces of milk in twenty-four hours, or two and a half ounces by day and two and a half ounces by night. It is best, however, to allow a little over, as some of it may be spilled, and the supply must not run short. Suppose, therefore, that in preparing the day's allowance, three ounces of milk and three ounces of barley-water are put in his jug, and the same amount allowed for night. Now, every two hours baby gets one ounce of this mixture during the first month of life. During the second month the quantity is doubled. The milk is still diluted by one half of water, or barley-water, but baby gets two ounces of fluid, one ounce of milk, and one ounce of barley-water. Gradually the strength of the milk is increased until, by the fourth or fifth month, baby is getting pure milk, probably five ounces at each meal every three hours.
To be continued.