CHAPTER XVI.

HABITATIONS.

THE first consideration in the selection of a site for a habitation is the nature of the soil with regard to dampness and organic impurity, since these are the principal factors in rendering a soil unhealthful. The house should stand upon a site the subsoil of which is naturally. dry, or is properly drained and free from impurity. The configuration of the surface, the elevation, and the exposure are important features in rendering the locality favorable for a healthy habitation. The nature, source, and amount of the water-supply should be investigated. The possibility for the economic and safe disposal of all refuse matter must also be considered. The locality should be sufficiently elevated to secure good drainage away from the house. A southern exposure is preferable, especially in colder climates. The proximity of large bodies of water and of marshy areas also influences the healthfulness of the locality.

The habitation should be so situated with relation to others surrounding it that an abundant supply of fresh air and sunlight can be secured. The healthful influences of sunlight and fresh air cannot be ignored. The absence of sunlight and deficiency of fresh air are the most important factors in producing disease in the homes of the poorer classes in our large cities.

Position of the House.-If possible, the house, especially when located on open ground, should face the south or west, in order to secure the greatest amount of sunlight in that portion of the house most constantly occupied. The windows require protection with blinds and awnings in summer, to exclude the heat and glaring

effect of the sun; but in winter the full and free action of sunlight should be secured, at least during a part of each day, because of its purifying influence upon the air of the house.

Foundation and Walls.-The foundations and walls should be as dry as possible, and in damp soils this can be secured only by draining the subsoil below the foundations, and by cementing the foundation walls and cellar floor. If there is no cellar, the floors should be raised about 0.5 meter above the ground, so as to secure thorough ventilation beneath the floor. Dryness of the walls

FIG. 56.-Double foundation walls.

is best secured by means of hollow walls (Fig. 56), or by coating the walls with cement or slate. Bricks are quite porous and absorb a great deal of moisture, and thus render the walls damp. Stone also is porous and retains moisture for a long time, consequently stone houses are liable to be damp.

The Roof. The roof of the house must be carefully constructed and frequently examined in order to prevent leaking. The material composing the roof is of no vital importance so long as it excludes rain. The rain-water falling upon the roof should be conducted away from the

house, so as to prevent the soil of the locality from becoming unduly damp from this cause.

The Interior Arrangement. The interior of the house should be arranged so as to afford the greatest facility for the use of every part of it for the purposes for which it is intended. The stairways should be wide and the steps broad, with easy slope, so as to prevent fatigue as much as possible in going from one floor to another. The rooms on each floor should communicate with each other, or with a common hallway, so as to favor easy access and insure more efficient ventilation.

Size of the Rooms.-The size of the rooms is a matter of the greatest importance in maintaining the purity of the contained air. The detrimental influence of insufficient air space is well known. The point of greatest hygienic importance is not how many rooms a person has, but how much room. A small room may be overcrowded with a single person in it, while a large room is not overcrowded with four to six persons in it. Aside from the matter of cubic space, the question of the dimensions of the room is of the greatest importance. The minimum. amount of cubic space allowable for sleeping-rooms per adult person is 10 cubic meters, though a room of 25 cubic meters is far more desirable. It is evident that a room 3 meters high is far more easily ventilated than one that is 10 meters high with the same amount of air space. Sleeping-rooms should be at least 2.75 meters high, though a height much in excess of 3 meters is not desirable. A room less than 2 meters in height is not suitable for a sleeping-room. The floor space of a sleeping-room should be at least 3 square meters. The livingrooms of a house should possess a cubic space of at least 12 cubic meters for each occupant, though an allowance of 30 cubic meters is preferable.

If the arrangements for ventilation are efficient, the air will require to be changed about three times an hour in a room of 25 to 30 cubic meters capacity, while in a room of only 10 to 12 cubic meters the air must be

changed seven to eight times an hour in order to maintain its purity. The living-rooms of a house should be correspondingly larger than the sleeping-rooms, in order to accommodate the larger number of persons occupying them, and the greater amount of exhalation from the body, and the greater amount of impurity derived from heating and lighting. It has been estimated that every lighted gas-burner requires from 12 to 15 cubic meters of fresh air per hour in order to prevent an undue amount of pollution of the air of a room from this source, and to maintain the standard of purity.

The Sleeping-rooms.-Lawson Tait, in a recent paper, gives his views on bed-rooms and bed-room furniture, based on a lifelong experience and observation. He directs that the bed-room shall have a capacity of 56 cubic meters, with tight-fitting doors and windows, and a ventilating flue of at least 1.5 decimeters in diameter. The window-panes should be of plate glass to prevent the too rapid cooling of the air of the room. He advises the construction of houses with double walls, with an air space between them of at least 0.75 decimeter, in order to prevent dampness of the walls. If possible, the room should be warmed by means of gas, as this is the best means of maintaining a uniform temperature. He directs that the bedstead shall be of steel or iron, 2 meters in length, and of a width sufficient to accommodate only one person. Two such bedsteads should be placed side by side. The danger of communicating such a disease. as consumption from one person to another while sleeping together is quite evident. The healthfulness of single beds is generally recognized, though in America, as in England, they are not in very common use.

The Floors and Floor - coverings.- Hard-wood floors are to be preferred, because they are less pervious to dust and therefore more easily kept in a sanitary condition.

The covering of the floors of a house has an important influence upon its healthfulness. Carpets and matting

are objectionable, because they are fastened to the floor and are allowed to remain in place for months or even years. It is preferable to have the floors painted and covered with a rug that can be removed, aired, and cleaned at frequent intervals.

The Wall-covering. The covering of the walls of rooms is a matter of the greatest importance. Wallpaper or paint of a bright-green or red color should be avoided, because these colors may contain arsenic. The arsenic in wall-papers will eventually become detached and be present in the air of the room as arsenical vapor. Sufficient arsenic has been found in the air of rooms, derived from these sources, to produce poisonous effects in those constantly breathing the air. The custom of placing a new layer of wall-paper on the old and soiled paper cannot be condemned too vigorously. This custom is very generally practised in spite of repeated remonstrances and warnings of the danger involved. All the filth contained on the old paper is allowed to remain on the walls, and is simply covered over with another layer of paper. This goes on until the number of layers of paper is so great that its weight prevents it from adhering to the walls any longer. Whenever a room needs papering, the old paper should be carefully removed and the walls scraped before a layer of new paper is placed upon them.

The prevalence of tuberculosis in certain houses year after year and generation after generation can be traced, at least in considerable part, to this custom of repapering the walls, as well as to neglect of disinfection and cleansing after death or removal of a case of tuberculosis. This condition will continue until compulsory registration of all tubercular patients is secured. The tubercle bacillus is capable of existing in the dust of rooms for a long time, and the inhalation of this infectious dust by susceptible persons is no doubt a frequent source of infection. When moving into an old house, therefore, it will be safest to give it a thorough cleansing and disinfection,