Rural Hygiene Part 5

Nor is it possible to conclude from the experiments and observations cited that the body remains indifferent to polluted air until the latter has reached a certain definite saturated condition. There can be little doubt but that a degree of pollution far short of that necessary to produce death has a weakening effect on the human organism, and that by means of the increased functional activity of other organs doing work intended for the lungs the resistance to disease is much impaired. Life is a continual struggle of the bodily tissues against the attacks of the micro-organisms and their tendencies to destroy life; hence inadequate ventilation or any other condition which interferes with the normal action of the organs of the body causes weakness and affords opportunity for the attack of some disease-producing germ. It stands to reason that an individual whose lung tissues have become soft and incapacitated must be more liable to succ.u.mb to disease than another whose lung capacity is large and whose blood has been continually and sufficiently oxygenated.

Perhaps no more impressive proof of this is seen than in the ravages of consumption, which is so p.r.o.ne to attack those whose vitality is diminished by living in unhealthy and unventilated cellars or in crowded tenements. Statistics are very definite on the subject of tuberculosis among Indians, who rarely suffer from the disease when living in tents or on the open prairie, but when they become semi-civilized and crowd together in houses heated through the winter months by stoves, the germs of tuberculosis take firm hold, and the deaths from this disease are greater in proportion to population among this race than anywhere else.

_Effect of change in air._

This discussion ill.u.s.trates another law of disease which makes the necessity for ventilation particularly great among rural communities where for nine months in the year outdoor life is freely enjoyed, namely, that when either an individual or people are brought under changed conditions, perhaps not unwholesome to those accustomed to them, those unaccustomed will suffer severely. So a lack of ventilation during the winter months in a farmhouse is very serious in its consequences to those who have had the full enjoyment of fresh air through the rest of the year.

Reference has already been made (in Chapter 1) to the prevalence of influenza in rural communities, and it is quite probable that this would be largely eliminated if the lungs were not deprived of their oxygen as they are in most houses on the farm.

_Composition of air._

Ordinary air contains about 0.04 per cent of carbon dioxid; that is, four parts in ten thousand parts of air, the other nine thousand nine hundred ninety-six being made up of oxygen and nitrogen. Of course, it is not possible to express any definite value for the amount of carbon dioxid which is objectionable in air, because, in the first place, it is not certain that the carbon dioxid in itself is the cause of diminished vitality due to insufficient ventilation, and, in the next place, insufficient ventilation affects different people in different ways. But it is known that in the lungs the life-giving oxygen is changed to carbon dioxid, and that just as carbon dioxid gas will prevent the combustion of a candle flame, so carbon dioxid gas will destroy the life of man.

When a deep well is to be cleaned out, the decomposition of organic matter in the bottom of the well will have, in all probability, caused the formation of this same carbon dioxid gas, and it is not uncommon for a man descending into such a well to be overcome by the gas, which, in some cases, even causes death. For this reason, it is common to lower into a well, before it is entered by a man, a candle or lantern, on the probability that if the lantern can stand it, certainly the man can, while if the lantern goes out, it is wise to avoid the risk of having a man's life put out in the same way.

_Organic matter in air._

The stuffy and close feeling perceived in an ill-ventilated room is, however, due to the organic matter from the lungs, which is expired along with the carbon dioxid, and some chemists have argued that this amount of organic vapor ought to be measured instead of the carbon dioxid.

At the present time there is no simple and direct method of measuring organic vapor, and because this vapor increases in the atmosphere proportionately to the carbon dioxid gas, it is much simpler to measure the latter. Then it is impossible to fix a standard of carbon dioxid because a person whose lungs are well developed and whose blood is well oxygenated, or, as we say, one who has good red blood can stand, even if uncomfortable, a few hours of a bad atmosphere without suffering serious discomfort, while an anaemic or poor-blooded person would be affected to a greater degree. It is for this reason that in any house no living room, especially one heated by a coal stove, should be shut up tight against fresh air. This is the reason why the women of the family, who have to breathe the same air over and over all day, are pale and weak and easily susceptible to disease, while the men, who are out of doors most of the time, and when indoors are made restless by the bad air, suffer much less from the ill effects.

Experiments seem to show that when the amount of carbon dioxid in the air has doubled, that is, when the expired air mixed with the air in the room has increased the proportion of carbon acid from four parts in ten thousand to eight parts in ten thousand, that the air is seriously affected, and that such ventilation ought to be provided that no greater amount than this could occur. This is such a condition that the room smells "close" or stuffy to a person coming in from outdoors, indicating organic emanations as well as an excess of carbonic acid gas. The question then is: how may this condition be avoided in an ordinary house, or in an ordinary stable, because the health of the cattle on a farm, judging at least by the character of the buildings provided, is quite as important as the health of the farmer's family.

We must take it for granted that no such elaborate schemes are possible as in public buildings or schools, where fans are provided, either to force air into the several rooms or else to suck it out. The ventilation of the house must be more simple and easily adjusted and must depend on the principle of physics that warm air rises and that if the warm air of a room is to be removed, air must in some way be supplied to take its place. The two essentials for ventilation are opportunity for the ingress and the egress of air--ingress for fresh air and egress for polluted air.

_Fresh-air inlet._

In the construction, of a dwelling house, special and adequate preparation for the admission of fresh air is seldom provided, so that the existing openings must be used for the purpose. This means that in the summertime an open window will furnish all the fresh air which a room receives and, when the temperature of the outside air is approximately that of the living room, such provision is ample and satisfactory. But in the wintertime, when the outside air is cold, the average person will prefer to suffer from the bad effects of impure air rather than admit cold air which may cause an unpleasant draft.

[Ill.u.s.tration: FIG. 14.--Letting in fresh air.]

One of the simplest and best methods of providing an inlet for fresh air, without at the same time allowing blasts of wind to enter the room, is to fasten in front of the lower part of the window a board which shall just fill the window opening; then, raising the lower sash a few inches will allow fresh air to enter both at the bottom, where the board is placed, and at the middle of the window between the sashes (see Fig.

14). Persons sitting close by a window thus arranged may feel a draft even under these conditions, since the cold air thus admitted will sink at once to the floor and then gradually rise through the room to the ceiling, but unless one sits too near the window, this is an admirable method of admitting fresh air.

Another method, where steam or hot-water radiators are placed in the room, is to connect the outer air, either through the lower part of the window or through the wall of the room just below the window opening, with a s.p.a.ce back of the radiator, so that the cold air entering will pa.s.s around and through the radiator and so be warmed as it enters.

[Ill.u.s.tration: FIG. 15.--Ventilating device.]

The picture (Fig. 15, after Jacobs) shows the arrangement of the radiators in one of the buildings of the University of Pennsylvania. A is the opening in the wall below the window; _D_ is a valve which regulates the amount of air entering through the opening; _R_ is the radiator; _B_ is a tin-lined box which surrounds the radiator; _T_ is a door in front of the box, which when raised allows the air of the room to be heated and to circulate through the radiator. By adjusting the two valves _D_ and _T_, air of any desired temperature can usually be obtained. Figure 16 (after Billings) shows an English device intended for the same purpose. The valve _D_ in this case operates to admit air, either through the radiator or to the s.p.a.ce between the radiator and the wall, in order to vary the temperature of the entering air. The valve _T_ may be open or closed, and its position, together with that of the valve _F_, determines the proportion of the room air which is reheated.

[Ill.u.s.tration: FIG. 16.--Ventilating device.]

The writer remembers one schoolhouse where these methods were used successfully, the radiators being placed directly in front of the window and inclosed at the back, sides, and top, except for an opening to the outer air through the wall, properly controlled by a damper. In the writer's own office the radiators are by the side of the window and are boxed in, the connection being made with the outside air through a wooden box entering under the radiator. This is an admirable method, provided the radiator has sufficient surface to warm the fresh air admitted.

Another excellent arrangement is to provide a narrow screen similar to that used for protection against flies, but with the screening material of muslin cloth instead of wire cloth. This muslin will break up the current of air so completely that no draft is felt by persons sitting even close to the open window.

_Position of inlet._

The inlet for fresh air, if connecting directly with the outside air, should not be at the top of the room, since then the inlet would not serve to admit air, but rather to allow the warm air of the room to escape, and a burning match would inevitably show a draft outward instead of inward.

Neither is it desirable to have the fresh-air inlet near the floor of the room unless the entering air is warm, because cold air admitted will flow across the floor and remain there, not disturbing the warm upper layers. The effect then is not to improve the ventilation, but only to chill the feet of persons sitting in the room. The position of the window lends itself, therefore, to admission of fresh air, since it is neither at the top nor at the bottom of the room, but at the level most suitable for such admission.

_Foul-air outlet._

Very few houses have any provision for the outlet of spent air, and if ventilation is thought of at all, the only idea usually is to provide, in part at least, for the admission of air and to make no adequate arrangement for its egress. Whenever a stove or fire-place is in use, the mere burning of fuel requires the consumption of air, and in cases where apparently no air is admitted to the room, insensible ventilation is at work bringing into the room, through the walls and through cracks around the doors and windows, the necessary air for combustion.

[Ill.u.s.tration: FIG. 17.--Ventilation by means of coal stove.]

It may be proved by the laws of physics that a coal stove burning freely in a room causes adequate ventilation; and that only where the dampers of the stove are closed, so that not merely is the supply of fresh air diminished, but also the products of combustion are thrown out into the room, is there danger from lack of ventilation. The stovepipe in this case furnishes the necessary outlet for the impure air, and the following suggestion has been made in order to utilize this outlet, even when the fire is not burning freely or when the damper in the stovepipe is closed. If the stovepipe from a stove is carried horizontally, as it usually is, an elbow must be provided to raise the pipe to the stove hole in the chimney. Then providing a T connection at the point marked _A_ in Fig. 17 (after Billings), the lower part of the _T_ may be carried to within a foot of the floor with a damper at the points _B_ and _C_. When the fire is burning freely, the damper at _C_ is closed, and ventilation is secured through the stove, the damper at _B_ being open. When the damper at _B_ is closed and the fire checked, then the damper at _C_ may be opened and the impure air drawn up the chimney from the level of the floor. This, it is said, is an effective arrangement for drawing off the polluted air of a room.

[Ill.u.s.tration: FIG. 18.--Coal-stove ventilation.]

Another method is to surround the stove with a sheet-iron casing, as shown in Fig. 18 (after Billings), the top of the casing having a pipe leading into the chimney independently from the stovepipe. The casing becomes warm and heats the room by radiation, just as the stove does, but if the damper in the flue from the casing be opened partly, a strong draft along the floor and into this casing will be developed and the foul air thereby discharged into the chimney. It will be easily possible, of course, to carry away all the heat from the stove in this method, and the damper in the flue of the casing must be carefully regulated to carry away only the desired amount of foul air.

[Ill.u.s.tration: FIG. 19.--Coal-stove ventilation.]

Still another method of using the heat of a stove to secure ventilation is shown in Fig. 19 (after Billings). Here the stove is surrounded with a sheet-iron jacket extending from the floor to about six feet above that level. A pipe is carried from the outside air up through the floor directly under the stove. By regulating the damper in this pipe the supply of fresh warmed air entering the room can be regulated. Doors in the casing must, of course, be provided for the purpose of taking care of the fire, and of allowing air from the room near the floor to be heated instead of the outside air.

A most objectionable method of providing an outlet for polluted air from a room is to have a register in the ceiling with the ostensible purpose of warming the room above. It was the writer's misfortune once to stay a week in the country, in a room over the kitchen where this method of heating was employed, and the odors of cabbage, onions, and codfish which permeated the upper room, and clung there all night, still remain as a most unpleasant memory.

_Size of openings for fresh air._

As an indication of the size of the openings needed, it has been said that in order to provide the necessary air movement, and yet to restrict the velocity of the moving air so that no objectionable drafts will be experienced, at least twenty-four square inches sectional area should be allowed as an inlet for each person, so that one square foot is required for six persons. This is, perhaps, a theoretical requirement. Certainly, it is more area than is likely to be obtained in actual ventilation. The s.p.a.ce between two windows, for instance, is about one inch by thirty inches,--barely enough, according to this rule, for one person, and yet that opening is sufficient to appreciably improve the quality of the air in a room occupied by three or four persons.

Taking into account the necessary air required by lamps or gas burners, the inlet flue should have at least ten square inches area for each person, so that the ordinary single register should provide the necessary amount of air for a living room. When, as happens in houses where a studied effort is made to preserve the health of the inhabitants, an outlet is cut into the wall and a flue carried up through the roof, the flue should be preferably near the floor and on the side of the room opposite the window or inlet. With such an arrangement (see Fig. 20) the air entering rises at first, but sinks at once because of the temperature, so that the direction of the air currents are diagonally across the room from the ceiling to the floor, thus renewing and changing all the air particles except those directly over the outlet. Where the air is introduced mechanically, that is, forced into the room, it is better to have the inlet and outlet on the same side, so that the entering air is shot in at the top, flowing across the room, then sinking and coming back, just below the point where it entered.

[Ill.u.s.tration: FIG. 20.--Outlets into the walls.]

_Ventilation of stables._

All that has been said on the subject of ventilation in houses applies equally well to the ventilation of stables, and a little book by Professor King of the University of Wisconsin, ent.i.tled "Ventilation,"

deals most thoroughly with the principles and practices of ventilation, not merely for dwellings but also for stables. Professor King proves by his experiments that the condition of cattle is much improved and that the milk-giving qualities are increased by a proper supply of fresh air, and in the book referred to, he gives a number of examples of the proper construction to provide adequate ventilation. It is most convincing to see how unscientific is the old-fas.h.i.+oned underground stable, the sole idea of which was to conserve the animal heat by crowding together the cows and by absolutely excluding the outside air. For further details of his work, its principles and practices, the reader is referred to the book, which may be obtained from the author at Madison, Wisconsin.

_Cost of ventilation._

To ventilate a house is expensive, and to ventilate a barn requires not only a certain expenditure of money but also a considerable amount of judgment. It is evidently cheaper to heat the same air in a room over and over than to be continually admitting cold fresh air, which will have to be warmed. This extra cost is, however, not excessive, when the movement of the air currents is properly controlled. The cost of warming the air necessary for ventilation for five persons should not be, at the rate of 1000 cubic feet of air to each person, more than ten cents a day in zero weather, with coal at five dollars a ton. Enough coal will have to be burned in addition to compensate for radiation, or, in other words, it requires a certain amount of coal to keep an empty room warm in winter without any question of ventilation, and in some badly built houses this amount is large.

_Relation of heating to ventilation._

It does not follow because much heat is lost in this way that the ventilation is good, since the heated air may ascend to the ceiling and there escape without influencing the ventilation. In fact, one of the first principles of ventilation is that as soon as regular inlets and outlets are provided, all other openings ought to be rigidly closed.

Then and then only can the warmed pure air be admitted as desired, at the points intended, and the full value of the heat utilized. Especially is this control of openings important in ventilating barns. Here each animal is a natural heater, warming the air by direct contact and by rapidly breathing in and out large volumes of air which are thereby changed to a temperature of over ninety degrees Fahrenheit. The air around their bodies being warmed rises to the ceiling and spreads out to the two sides and is there gradually cooled and at the same time mixed with fresh air which enters at the top, so that the cow is constantly supplied with freshened air. A flue is needed to carry the foul air up through the roof, and fresh-air inlets in the outer walls on both sides are required, and with these openings carefully controlled and with no others interfering, the stable may be well ventilated, as shown in Fig.

21 (after King).

[Ill.u.s.tration: FIG. 21.--Cow-barn ventilation.]

In all cases where ventilation is to be practiced, the walls and ceiling should not merely be tight in themselves, but they should be double, and the strictest attention paid to limiting the amount of heat lost by radiation. All the heat used ought to be concerned in ventilation, and in that only. To secure air-tight walls and ceiling, the studding and joists should be boarded in, both on the inside and out, and the s.p.a.ce between should be filled with shavings, straw, dry moss, or any similar fibrous substance. The outside sheathing must be well laid and must be water-tight in order that rain shall not penetrate to the inside of the wall, and the roof must be tight so that the ceiling filling does not get wet and rot.

The choice, therefore, so far as ventilation of either house or barn goes, lies between a poorly built, loose-jointed structure without artificial ventilation and with poor economy in heat, and a well-built, air-tight structure, with ample ventilating pipes, carefully and intelligently planned and built. The first is healthy so far as pure air is concerned, but drafty and uncomfortable. The second is more expensive to build, but insures lasting health and comfort. Then the choice cannot but fall on the building which is easy to warm, healthful to live in, and readily ventilated.