Physiology and Hygiene for Secondary Schools

by Francis M. Walters

Fig. 168—Contamination of cistern water by birds nesting in the gutter trough.

Shallow wells are to be condemned, as a rule, because of the likelihood of surface drainage (Fig. 169), and water from springs should, for the same reason, be used with[pg 399] caution. Deep wells that are kept clean usually may be relied on to furnish water free from organic impurities, but such water often holds in solution so much of mineral impurities as to render it unfit for drinking. The presence in water of any considerable quantity of the compounds of iron or calcium makes it objectionable for regular use.

Fig. 169—Sources of contamination of cistern and well water. Illustration shows liability of contamination from surface drainage and from entrance of filth at top.

Hygienic Housekeeping.—However carefully a house has been constructed from a sanitary standpoint, the constant care of an intelligent housekeeper is required to keep it a healthful place in which to live. Daily cleaning and airing of all living rooms are necessary, while such places as the kitchen, the cellar, and the closets need extra thoughtfulness and, at times, hard work. Moreover, the problem is not all indoors. The immediate premises must be kept clean and sightly, and all decaying vegetable and animal matter should be removed. Home sanitation consists,[pg 400] not of one, but of many, problems, all more or less complex. None of these can be slighted or turned over to a novice.

Destruction of Infectious Material.—At times the housekeeping has to be directed especially toward hygienic requirements, such an occasion being the sickness of one of the inmates with some contagious disease. Unless special precautions are taken, the disease will spread to other members of the household and may reach people in the neighborhood. Not only must great care be exercised that nothing used in connection with the sick shall serve as a carrier of disease, but germs passing from the patient should, as far as possible, be actually destroyed. All discharges from the body likely to contain bacteria, should be burned or treated with disinfectants and buried deeply at a remote distance from the water supply to the house.

After recovery all clothing, bedding, and furniture used in connection with the sick should be disinfected or burned. The room also in which the sick was cared for should be thoroughly disinfected and cleaned; in some instances the woodwork ought to be repainted and the walls repapered or calcimined. The purpose is, of course, to destroy all germs and prevent, by this means, a recurrence of the disease.

Fumigation.—To destroy germs in the air or adhering to the walls of rooms, furniture, clothing, etc., fumigation is employed. This is accomplished by saturating the air of rooms with some vapor or gas which will destroy the germs. Fumigation is quite generally employed in the general cleaning after the patient leaves his room. This, to be effective, must be thorough. Formaldehyde is considered the best disinfectant for this purpose, and it should be evaporated with heat in the proportion of one half pint of the 40 per cent solution to 1000 cu. ft. of space. Since formaldehyde is inflammable and easily boils[pg 401] over, it has to be evaporated with care. It should be boiled in a tall vessel (a tin or copper vessel which holds about four times the quantity to be evaporated) over a quick fire, the room being tightly closed (openings around windows and doors plugged with cotton or cloth). After three or four hours the room may be opened and thoroughly aired. Since formaldehyde is most disagreeable to breathe, one should not attempt to occupy the room until it is free from the gas. This will require a day or more of thorough ventilation.

Facts Relating to the Spread of Certain Diseases.—The problem of preventing disease in general often resolves itself into the problem of preventing the spread of some particular disease. It is then of vital importance to know the special method by which the germs of this disease leave the body of the patient and are conveyed to the bodies of others. Some of these methods are novel in the extreme, and are not at all in accord with prevailing notions. Particularly is this true of that disease known as

Malaria, or Malarial Fever.—This disease, so common in warm climates and also prevalent to a large extent in the temperate zones, is due to animal germs (protozoa), which attack and destroy the red corpuscles of the blood. These germs, it is found, pass from malarial patients to others through the agency of a variety of mosquitoes known as Anopheles. In sucking the blood of a malarial patient, the mosquito first infects her own body.[131] In the body of the mosquito the germs undergo an essential stage of their development, after which they are injected beneath the skin of whomsoever the mosquito feeds upon. For the spreading of malaria, then, two conditions are necessary: first, there must be people who have the disease; and second, there must be in the neighborhood the special variety of mosquito that spreads the disease.[pg 402] If either condition be lacking, the disease is not spread. The malarial mosquito (Anopheles) may be distinguished from the harmless variety (Culex) by the position which it assumes in resting, as shown in Fig. 170.