Fig. 3.—A grading that turns water away from the house.Fig. 3.—A grading that turns water away from the house.
Too much emphasis cannot be laid on the necessity for grading the ground surface away from the house. In some cases it may be sufficient to dig a broad shallow trench protected from wash by sods (Fig. 3). In other cases it may be desirable to pave the ditch with cobble stones or to build a cement gutter. In constructing such a surface drain, proper allowance must be made for theaccumulation of snow and the resulting amount of water in the spring, so that the distance in which the ground slopes away from the house ought to be, if possible, at least ten feet, so that there can be no standing water to penetrate the house walls. The slope necessary to carry surface water away need not be great. A fall of one foot in one hundred will be ample, even on grassy areas, and if the surface is that of a macadam road or the gutters of a drive, this grade may be cut in two. A slope of more than one foot in one hundred is permissible up to a maximum of seven or eight feet per hundred, more than this being æsthetically objectionable and tending to make the house appear too high. Whenever gutters are built in driveways or ditches to intercept water coming down the slopes, a suitable outlet must be provided to carry the water thus collected either into underground pipes, by which the water is led to some stream or gulley, or directly into some well-marked surface depression.
Ground water.
The soil always contains water at a greater or less depth, and the elevation of this "ground water," as it is called, varies throughout the year partly with the rainfall and partly with the elevation of the water level in the near-by streams.
It is not at all unusual for this ground water to rise and fall six feet or more within the year, high levels coming usually in the spring and fall, and low levels in the late summer and winter. It is easily possible, then, that a house cellar may seem dry at the time of construction in summer and may develop water to a foot or more in depth after occupancy. The presence of such an amount ofwater in a cellar, whether injurious to health or not, is objectionable, and a subsoil trench should be provided in order to limit the height to which ground water may rise.
If a system of drainpipes is led around a house extending outward to include the surrounding yard, then the ground water will always be maintained at the level of those pipes, provided the system has a free outlet. Indeed, the question of an outlet for a drainage system is a most important factor, and no system of underdrains can be effective unless a stream or gulley or depression of some kind is available into which the drains may discharge. It is for this reason, quite as much as for any other, that the location of a house on a perfectly level bottom land is objectionable, since the ground there may be normally full of water with no existing depression into which it may be drained.
In the next chapter the proper method of laying drains close to the cellar wall, for the purpose of taking away the dampness from those walls, is described, but another system of drains is desirable, covering more area and more thoroughly drying the ground, provided the ground water needs attention at all. These drains should be laid like all agricultural drainage; and while substitution of broken stone, bundles of twigs, wooden boxes, or flat stone may be made, the only proper material to be used is burnt clay in the form of tile. These tiles are made in a variety of patterns, but the most common in use to-day is one which is octagonal outside and circular inside. They are about one foot in length and may be had from two to six inches inside diameter. The ordinary size forlaterals is four-inch diameter, while the mains into which these laterals discharge are generally of six-inch diameter. These tiles are laid in trenches about fifteen feet apart, although in porous soil, such as coarse sand or gravel, this distance may be increased to twenty feet. If the tiles are laid more than four feet below the surface, this distance may be increased, and if the tiles are five feet deep, the distance apart of the several lines may be fifty feet.
The grade of the line must be carefully taken care of, and while it is possible to lay a line of tile with a carpenter's level and a sixteen-foot straightedge, it is much safer to have an engineer's or architect's level and set grade stakes, as in regular sewer work. A fall of one fourth of an inch to the foot is a proper grade, although a greater slope is not objectionable. It is sometimes desirable in soft ground to lay down a board six inches wide in the bottom of a trench on which to rest the tile, but, unless the ground is very soft, this is not necessary. Care must be taken, however, if the board is not used, to have the bottom of the trench very carefully smoothed so that a perfectly even grade in the tile is maintained. There are three ways of laying out a line of trench as shown in the following sketches (Fig. 4). It is usually sufficient to run parallel lines of tile from fifteen to fifty feet apart over the area which it is desired to drain, and let the ends of these lines enter a cross line which shall carry off the water led into it. This cross line should be six inches in diameter as a general rule, unless there is more than a mile of small drains, in which case the size of the cross pipe ought to be increased to eight inches. This cross line then becomes the main outlet, and great care must be taken to see that it has a perfectly free delivery at all times of the year. In cities and sometimes in small villages it is possible to discharge this outlet pipe into a regular public sewer, provided the sewer is deep enough, and provided the municipal ordinances allow such a connection. Otherwise, the outfall must be carried to a natural depression.
Fig. 4.—Modes of laying out drains.Fig. 4.—Modes of laying out drains.
In level ground, the problem of finding a suitable outlet is a serious one, and in many cases impossible of solution, so that the householder, being unable to find an outlet, must put up with the ground water and be as patient as possible during its prevalence. It does not do to trust one's eye to find a practicable outlet, since even a trained eye is easily deceived. An engineer with a level can tell in a few moments where a proper point of discharge may be found, and it is absurd to begrudge the small amount which it will cost, in view of the large expense involved in digging a long trench to no purpose.
Some years ago the writer was able to note the conditions in a house where the cellar excavation went three feet into limestone rock. The strata were perfectly level and the cellar floor of natural rock was apparently all that could be desired, smooth and flat, without involving any expense for concrete. One wall came where a vertical seam in the rock existed, and since this natural rock face was smooth and vertical and just where the cellar wall should go, it seemed unnecessary to dig it out and lay up masonry in its place. So it was left and the house built. When the spring rains came, however, the cellar was turned into a pond, water dripping everywhere from the vertical rock face, and coming up through the cellar bottom likesprings. It cost a great deal more then to make the changes and improvements necessary in order to secure a dry cellar than it would have done at the outset. This serves as an illustration of the need of taking every precaution at the beginning to insure a dry and well-drained soil around and below the cellar walls.
Any liability to disease that may come from faulty construction of habitations is likely to spring from a polluted subsoil. Such pollution vitiates the air drawn from that soil and is a source of danger on account of the resulting impurity of the whole atmosphere within the house.
Shutting out soil air.
We have already seen (Chapter II) how it is possible for soil charged with organic matter to deliver, either through suction from a heated house or on account of a rising ground water, soil air into the cellar, and also that moist air may enter the house in the same way. In order to prevent this, it is plainly necessary to interpose some air-tight or water-tight layer between the house and the soil, and also, since perfection in this layer is impossible, to make provision for draining away any water which may accumulate against the walls. Ordinary builders do not lay much emphasis on the importance of either of these precautions, and while one may often see cellar walls roughly and carelessly coated on the outside, with tar or asphalt, a thoroughly water-tight coating is not a commonpractice. Similarly, while draintile are often laid around a house, they are either laid so near the surface as to be useless or else they have no porous filling.
Fig. 5.—Exterior wall-drains.Fig. 5.—Exterior wall-drains.
To prevent moisture from entering the cellar, the first provision should be a tile drain (not less than four inches in diameter) laid completely around the house (see Fig. 5) on a grade of not less than six inches in one hundred feet. This drain at its highest point ought to be one foot below the bottom of the concrete floor of the cellar, and more than this, of course, at the lower end. This should be laid before or at the time the foundations for the house are being built, although it is possible to dig the necessary trenches and lay the tile after the house is built. If the available grade is small, this drain may be laid in two lines directly under the cellar floor as shown in Fig. 6. At the pointsAthe bottom of the tile should be at least a foot below the dirt on which the cellar floor will be laid, and at the pointB, about two feet. This drainpipe is best laid with regular sewer pipe and without cement in the joints. Then coarse gravel should be filled in around this tile so as to allow water to enter the pipe without carrying soil that later might settle in the pipe.
Fig. 6.—Interior cellar-drains.Fig. 6.—Interior cellar-drains.
Position of outfall.
There is always a question of where this drain shall end and into what it shall discharge, for in some soils this drainpipe may discharge continually. To allow the drain to empty on the ground means that its outer end will be broken; that if discharge takes place just before freezing weather, the drain will fill with ice and be broken, so that some other method must be devised. If the outer end can be laid into a brook where the velocity prevents the water from freezing, or where the outer end can be kept below water, a satisfactory disposal is found. Otherwise, it is better to discharge into a small covered cesspool, provided the soil is sufficiently porous to take care of the water, and provided the level of the ground water allows the construction of such a cesspool. In any case, it should be at some distance from the house, so that if it overflows, the water will not seep back to the cellar walls. By water-proofing the main wall and then backfilling against the wall with coarse gravel or broken stone, the same results as with open areaways are obtained and at a much smaller cost.
Dampness of masonry walls.
One fact peculiar to all kinds of masonry and known to all careful observers is that stone work, brick work, and concrete will allow dampness to permeate, whether it comes from water-bearing soil or a driving rain. One objection to concrete-block houses has been that a hard rain would cause moisture to form on the inside. Brick buildings have the same defect when the walls are built solid.
An air-space in the cellar walls is the only way of insuring a dry cellar, if the bottom of the cellar is below thelevel of the ground water. A four-inch course of hollow brick may be used on the inside, or the wall may be actually divided into two walls with a space between.
Fig. 7.—Wall modes of making air-space.Fig. 7.—Wall modes of making air-space.
Figure 7 (after Warth) shows three different ways by which an air-space is secured and the two component parts of the wall held together. In the top view, the two walls, one eight-inch and one four-inch, are held together by wire ties, leaving an air-space of about four inches. In the middle drawing the walls are tied together by making the air-space three inches wide and then lapping the brick laid as headers over both walls. In the bottom view special terra-cotta blocks are used which pass through both walls. There can be no question of the value of such construction in eliminating dampness from the inside wall, but, it must be admitted, the cost of the walls is increased somewhat.
Use of tar or asphalt on the wall.
Instead of an open space, nowadays, it is more customary to thoroughly plaster the outside of the cellar wall,and then paint it with a tar paint put on hot, which will adhere fairly well to the cement or masonry. Asphalt cannot be very readily used for this purpose unless it is an asphalt oil with but little bitumen paste. A paving asphalt, for example, even applied hot, does not adhere to the masonry, but slides down the walls as fast as it is applied. A successful method, however, of using such asphalt is to build the cellar wall in two parts, separated about half an inch, and filling in the intervening space with liquid asphalt. In this way, the asphalt is held in position, and is an absolute prevention of dampness.
Another method used successfully in the construction of one of the large railroad stations in Boston consists in painting the outside of the wall with tar and then pressing into the hot tar several layers of tar paper, the separate sheets overlapping in a special coating of tar. These sheets are thus made continuous around the building and under the basement so that no water can enter the building.
Fig. 8.—Water-tight wall.Fig. 8.—Water-tight wall.
A cross-section of one of the depressed tracks entering the Boston Station is shown in Fig. 8. The heavy black line represents ten thicknesses of tar paper, each one thoroughly painted with a thick paint of hot tar. It should be noticed that this water-tight coating is inclosed between masonry walls, so that the coating cannot be injured.
It is possible theoretically by these methods to build an underground cellar so truly water-tight that it could be set down in a lake, where it might float like a boat and not leak a drop, and there may be some locations that require such construction, such as a low river valley or an old salt marsh or a city flat, where no adequate drainage is provided. But practically such construction will always be found expensive, and is, in most cases, unnecessary and ineffective, as already indicated, and where the percolating water cannot be tolerated, involves the installation of some kind of pump to throw out the water that will inevitably, in larger or small quantities, pass through the best water-proofing. It is, therefore, the part of wisdom to place reliance on draining the water away from the house rather than on water-proofing the cellar wall.
Dry masonry for cellar walls.
It may not be out of place to add a word of caution against the practice of building cellar walls of loose stone, without mortar. They make no pretense of being water-tight, they offer no resistance to the entrance of rats, and they soon yield to the pressure of the earth and present that wobbly, uncertain appearance of cellar walls seen in rural districts. Nor should the idea that the interior is to be visible and the exterior invisible blind the builder to the fact that it is far more important to have the outside smooth. If smooth, there are no projecting surfaces for water to collect in, no edges for the frozen earth to cling to and by expansion tear off from the wall. If smooth, the joints in the masonry can be pointed or filled with mortar, and thus a suitable surface for the tar or asphalt is provided.
Fig. 9.—Rough-backed wall.Fig. 9.—Rough-backed wall.
In Fig. 9 (after Brown) is shown a cellar wall with rough, irregular back, and it is easy to see how water would readily find its way down to one of the projecting stones and then along such a stone, through the wall into the cellar. With such a wall the action of the frost is more severe than with a wall with a smooth back, so that the wall in Fig. 9 is gradually pulled apart by alternate freezings and thawings. Figure 10 (after Brown), on the other hand, shows the cellar wall as it should be with smooth, even exterior, along which the water passes easily, with gravel backing, through which the water escapes to the drainpipe.
Fig. 10.—Even-backed wall.Fig. 10.—Even-backed wall.
Damp courses in walls.
Fig. 11.—Four modes of making water-proof cellar walls.Fig. 11.—Four modes of making water-proof cellar walls.
Another important means of keeping moisture from the cellar walls is to provide what is called a damp course at about a level with the top of the cellar floor. Where the soil is naturally damp, and where the cellar wells are not adequately water-proof, a second damp course should be provided at the level of the ground so that moisture from the damp cellar walls may not pass up into the above ground portion, which is naturally dry. These damp courses, in their simplest form, consist in bringing the masonry level around the building, and painting the top surface with liquid coal tar.
Fig. 12.—Waterproofing of cellar walls.Fig. 12.—Waterproofing of cellar walls.
Another method is to paint the masonry with liquid asphalt, and then imbed in this paint a thickness of asphalt-covered building paper which is again painted with asphalt. This may be done in the horizontal layer where it could not conveniently be done vertically.
Four different ways used in France for securing dry cellar walls are shown in Fig. 11. The heavy black line represents the damp course, which, when added to the effect of the interwall space, which is shown in all the drawings but the first, and there replaced by a deep drain, insures absolute freedom from all moisture within the cellar. Figure 12 shows sections recommended by Dr. George M. Price, and indicates clearly the location of the damp course.
The cellar floor.
The floor of the cellar, in the same way, must be kept from dampness, and this is best done by covering the cellar floor with a layer of concrete, one part cement, three parts sand, and six parts broken stone; or, one part cement and eight parts gravel may be used. Care should be taken, however, that the gravel does not contain an excess of sand, and it is always well in using gravel for concrete to check the proportion of these two materials. This may be done as follows: Sift the gravel through an ash sieve so that it is free from sand; fill a ten-quart pail even full with the gravel and then pour in water to the top of the pail, keeping account of the amount of water poured in. This volume of water gives the proper amount of sand to use with the gravel for concrete, and if more sand than this was present in the original gravel, it should be sifted out until the proper proportion is reached.
Concrete is not water-tight, and the concrete floor of the cellar must be treated in some way to prevent water or moisture rising through this floor. One method is to cover the concrete thus laid with a denser mixture of cement and sand, put on three fourths of an inch thick, and made by mixing equal parts of sand and cement; or the asphalt layer already referred to in the cellar walls may be carried across the cellar, putting, as before, a paint layer on the concrete, then paper, then another paint layer, making it continuous and without a break from outside to outside. On top of this, to prevent wear and tear, a floor of brick, laid flat, or a two-inch layer of concrete may be laid.
Cellar ventilation.
The great importance of the cellar as that part of the house where, if anywhere, unhealthy conditions exist, justifies this prolonged discussion, and before leaving the subject, ventilation in the cellar should receive a word of encouragement. Too many cellars are damper than need be, are musty and close, full of odors of decaying vegetables and rotting wood, entirely from lack of ventilation. The cellar windows are small and always, closed. The cellar door is seldom opened, and never with the idea of admitting air. The impression on entering such a cellar is of a tomb.
The cellar, even in that part devoted to storing vegetables, needs ventilation as much as the house does, for the cellar air finds its way up into the house, and an unventilated cellar means a house with air deficient in oxygen and overloaded with carbonic acid, a condition which causes pale faces and anæmic bodies. Far better andhealthier is it to open all the cellar windows, covering them with coarse netting to keep out animals and with fine netting to keep out insects, and let the disease-killing oxygen and sunlight in. Malaria comes from the cellar, whenever the malarial mosquito can find there a breeding place. The writer has seen many cellars in which mosquitoes were living the year through in entire comfort, utilizing the moisture and warmth of the cellar to enjoy the winter months and up and ready for their mission at the first sign of spring. A cistern in the cellar is objectionable on this account, and if one exists, it should be covered with mosquito netting.
The old-fashioned privy.
Another source of ill-health as well as of temporary discomfort is the typical construction and continued use of an outside closet or privy. The physical shrinking from the use of the ordinary building is most reasonable. As generally constructed, great draughts of air (presumably for ventilation) are continually passing through the small building, and when the temperature of the outside air is at zero, or thereabouts, only the strongest physique can withstand the exposure involved without serious danger of consumption, influenza, and pneumonia, or at least inviting those diseases by reducing the vitality of the body. Two improvements suggest themselves and should be put into effect wherever this primitive construction must continue to be used.
In the first place, the building itself should not be fifty or a hundred feet away from the house, so that every one is exposed to rain, snow, slush, and ice in making the journey thither. But some corner of the woodshed orbarn should be utilized or the small building should be moved up by the back door and connected therewith by a roofed passage. The barn location is objectionable if it involves outdoor exposure in going from the house to the barn. A liberal use of earth in the privy vault will eliminate odors, and a water-tight box or bucket makes a frequent removal of the night soil practicable.
In the second place, a small stove ought to be provided to warm the closet in the coldest weather. Then the dislike to suffer from the cold, which leads so many to postpone nature's call, will be avoided, and the consequent digestive disorders which come from constipation and intestinal fermentations prevented.
Cow stables.
In matters of health, aside from ventilation, which is discussed in the next chapter, there is little to be said concerning the other buildings on the farm. Barns for hay are not involved. A few words may profitably be devoted to barns for stock, involving, as they do, by their construction, the health of the stock. One enthusiastic farmer writes that it is possible for farmers to keep their stock at all times under conditions which are an improvement upon the month of June. He believes that the cow stable should be as comfortable for the cows as the house is for the owner, subject to no fluctuations of temperature, and that, in this way, the health as well as the comfort and milk production of the cows would be maintained.
Light should be listed as the first essential of healthy stables, light to kill disease-producing bacteria, to make dirty corners and holes impossible, and to react on thevitality of the animals. Compare this with some stables where fifteen, twenty, or thirty head are stabled in an underground dugout with two or three small windows not giving more than four square feet in all. Stable windows should be set, like house windows, in two sashes and capable of being raised or lowered at will. In winter a large sash may be screwed over the regular window to keep out frost and moisture, provided there is some independent method of ventilation.
For good healthy conditions, a cow needs about 500 cubic feet of space, with active ventilation. In old stables, with poor construction, as little as 200 cubic feet per cow was allowed, and when stables were made tight with matched boards and building paper, 200 cubic feet was found to be too small, and it was recommended that one cubic foot be allowed for each pound of cow. But when tried by wealthy amateurs, it was found that this was too large; the stables were damp and cold in winter and became a predisposing factor in the development of tuberculosis. Between the two extremes, 200 and 1000, is the practical average named above, namely, 500 cubic feet of air space for each cow.
For the health of the cow as well as for the good quality of the milk the stable should be built with special reference to being kept clean. The ceiling should be dust-tight, so that if hay is stored above, it will not sift through. The part of the barn where the cows are kept should be separated from the rest of the barn by tight partitions and a door into the cow stable. Nothing dusty or dirty should accumulate. The floor of all stables for cows, horses, hens, and pigs should be of concrete to insure the mostsanitary construction. Planks absorb liquids and wear out rapidly under the feet of the stock. Concrete can be kept clean, is nonabsorptive, and if covered with some non-conducting material, like sawdust, shavings, or straw, is a perfectly comfortable floor for the animals.
Use of concrete.
No development of recent times has tended more toward the improvement and greater comfort of house building than the use of concrete. In the earlier houses, the cellar walls were so badly built and the connection between the top of the cellar wall and the timber sill of the house was so poor that the winter's wind blew through above to the manifest discomfort of those in the house. The writer remembers sitting in the best room of a well-to-do farmer, and watching, with great interest, the carpet rise and fall with the gusts of wind outside. To avoid such unhappy consequences, farmers have been accustomed to bank up the house outdoors in the fall with dry leaves, spruce-boughs, or manure, usually to a point on the woodwork. This, of course, closes the cellar windows for the winter for the sake of keeping out the wind. A concrete wall, at the present price of cement, using gravel for the mixture instead of stone, need cost but little more than the price of the cement and the labor involved, and a tight cellar wall may thereby be obtained.
If the soil in which the cellar is dug is firm enough, the outside of the excavation can be made so that no form on that side will be required, but it is always better to make the excavation about two feet more than necessary, to put forms inside and outside, and, after their removal, plaster or wash the wall with a thick cream of cementand water. In carrying the wall above the ground, forms must be used with great care to secure a smooth surface, and Fig. 13 shows two methods suggested by the Atlas Cement Company.
Fig. 13.—Cellar-wall forms.Fig. 13.—Cellar-wall forms.
There are so many forms of construction where concrete is not merely a convenience but a great advantage in the matter of health around the house, and particularly a house in the country, that there would be no end if one once began enumerating and describing the various methods and processes involved. Besides the cellar walls and cellar floor, there are outside the house, silos, manure bins, walks, curbing, steps, horse-blocks, hitching and other posts, watering troughs, and drainpipe, all successfullymade of this useful material. In the barn, the barn floor, the gutters, the manger and watering troughs, cooling tanks, and sinks are also made of cement. While it is possible to differentiate between the methods and the mixtures for these various purposes, it will not be greatly in error if the construction always follows the following principle.
Use enough cement to fill the voids in the gravel or in the sand and stone mixture employed, and have enough sand in the gravel or with the stone to fill the voids in the stone. This is readily determined, as already suggested, by the use of water. The water, which will occupy the voids in the stone, represents the necessary sand. When this amount of sand and stone is well mixed, the water then permeating the interstices represents the necessary cement, though it is a good plan to add about 10 per cent extra to allow for imperfect mixtures.
The mixing should always be done so thoroughly that when put together dry, no variation can be seen in the color of the mixture. It is surprising to see how readily a streak of unmixed dirt or of unmixed cement can be detected in a pile by the difference in the color which it presents. Such mixtures should always be made dry first and then the water added and again mixed until the result is of a perfectly firm consistency. Such a mixture can be applied to any of the purposes mentioned, and, in general, it is better to have too much water than not enough. The only difficulty with a very wet mixture is that the forms require to be made nearly water-tight, whereas with dry mixtures the same attention to the forms is not necessary.
If the concrete is to be used in thin layers, as in pipe or watering trough, where a smooth surface is wanted, betterresults are usually obtained by using a dry mixture and fine gravel and tamping the mixture with unusual thoroughness. It is always unsafe to smooth up or re-surface a piece of concrete. The difference in texture of the surface coat causes it to expand and contract differently from the mass of concrete underneath, and inevitably a separation occurs. If it is desired to put on a sidewalk, for instance, a smooth top coat, the consistency of the two kinds of concrete should be alike, and the top coat should be applied almost immediately after the bottom layer is put in place. Where concrete is used to hold water, a coat of neat cement should always be put on with a broom or a whitewash brush, mixing the neat cement with water in a pail, and it does no harm to go over the surface three or four times, the object being to thoroughly close the pores in the concrete.
For floors of cellars or barns, the dirt should be evened off and tamped and then the cement concrete should be spread evenly over it, and tamped just enough to bring the water to the surface. When partially dry, a better finish is obtained by lightly troweling the concrete. In a cellar or barn, it is not necessary to divide up the area into squares or blocks as is done with sidewalk work, but the entire area may be laid in one piece. In order to keep the surface level, however, it may be found convenient to lay down pieces of 2" x 4" scantling, the tops of which shall be on the desired level of the finished floor. By filling in behind these scantlings, which can be moved ahead as the filling progresses, the exact level desired can be obtained. Usually four inches thick will be a proper depth of concrete for this purpose.
The average individual breathes in and out about eighteen times a minute, taking into his lungs the air surrounding him at the time and expelling air so modified as to contain large amounts of carbonic acid, organic vapor, and other waste products of the lungs. The volume of air taken in is about the same quantity as that expelled and amounts to eighteen cubic feet per hour. Fortunately, the air expired at a breath is at once rapidly diffused throughout the surrounding atmosphere, so that, even if no fresh air were introduced, the second breath inhaled would not be very different from the first. But after a certain length of time the air becomes so saturated with the waste products of the lungs that it is no longer fit to breathe, and it is evident that in order to keep the air in a room so that it can be taken into the lungs with any reasonable degree of comfort, there must be a continual supply of fresh air admitted with a proper provision for discharging polluted air. If this is not done, there is, so far as the lungs are concerned, a process established similar to that which is occasionally found when a village takes its water-supply from a pond and discharges its sewage into the same pond.
Not long ago, the writer found in the Adirondacks a hotel built on the side of a small lake which pumped its water-supply from the lake, and discharged its sewage into the same lake only a few feet away from the water intake. That the hotel had a reputation of being unhealthy, and that it had difficulty in filling its guest rooms, is not to be wondered at, and yet individuals will treat their lungs exactly as the hotel treated its patrons.
Effects of bad air.
In order to establish a proper relation between the amount of impurities diffused through the air and the physiological effect on individuals breathing that air, certain observations have been noted and certain experiments have been made which prove without question the injurious effect of vitiated air.
Professor Jacob, late Professor of Pathology, Yorkshire College, Leeds, gives the following example on a large scale, to show the results of insufficient ventilation: "A great politician was expected to make an important speech. As there was no room of sufficient dimensions available in the town, a large courtyard, surrounded with buildings, was temporarily roofed over, some space being left under the eaves for ventilation. Long before the appointed time several thousand people assembled, and in due course the meeting began; but before the speaker got well into his subject, there arose from the vast multitude a cry for air, numbers of people were fainting, and every one felt oppressed and well-nigh stifled. It was only after some active persons had climbed on the roof and forcibly torn off the boards for a space about twenty feet square that the business of the meeting could be resumed."
Remembering that the process of breathing is for the purpose of supplying oxygen to the blood and that the absorption of oxygen in the lungs is the same process which goes on when a candle burns, the following experiments were made by Professor King of the University of Wisconsin, to show the effect of expired air on a candle flame. He took a two-quart mason jar and lowered a lighted candle to the bottom, noting that the candle burned with scarcely diminished intensity. Through a rubber tube, he breathed gently into the bottom of the jar, with the result that the candle gradually had a reduced flame and was finally extinguished. He observed also that if the candle were raised as the flame showed signs of going out, the brilliancy of the flame was restored, while lowering the candle tended to extinguish the flame. Even when the candle was raised to the top of the jar, the flame was extinguished after sufficient air had been breathed into the jar. Clearly, then, he argued, air once breathed is not suitable for respiration, unless much diluted with pure air. He argued from this that if a candle using oxygen for combustion could not burn in expired air, therefore an individual using oxygen for the renewal of the blood could not be properly supplied in a room partially saturated with the expired products of the lungs.
Professor King also experimented with a candle burning in a jar on which the cover had been placed, and found that the candle was extinguished in thirty seconds, and he argued that if a candle was thus extinguished on account of the carbonic acid given off, so a person shut up in an air-tight chamber would similarly be extinguished in the course of time.
To prove that expired air is poisonous to animal life, Professor King experimented on a hen, placing the same in a cylindrical metal air-tight chamber eighteen inches in diameter and twenty inches deep. The hen became severely distressed for want of ventilation and died at the end of four hours and seventeen minutes.
In the Wisconsin Agricultural Experimental Station, an experiment was conducted for fourteen days on the effect of ample and deficient ventilation on a herd of cows. The stable was chiefly underground and had two large ventilators which could be opened or closed at will. The food eaten, the water drunk, the milk produced, and weight of the cows were recorded each day. For a part of the time the cows were kept continuously in the stable with all openings closed, and then the ventilators were opened, the alternate conditions being repeated at intervals of four days. The amount of food consumed was practically the same under both conditions. The quantity of milk given was greater with good ventilation. The chief difference was in the amount of water consumed, since with the insufficient ventilation the cows drank on the average 11.4 pounds more water each, daily, and yet lost in weight 10.7 pounds at the end of each two-day period. Examination of the animals themselves also showed that a rash had developed on their bodies which could be felt by the hand and which was apparently very irritating, since it was so rubbed by the animals as to cause the surface to bleed. The evident teaching of the experiment is that under conditions of poor ventilation, it was impossible for the lungs to remove waste products to as great an extent as usual, and, therefore, the demand foradditional water was felt in order to stimulate greater action on the part of the kidneys to care for these waste products. That this was not a successful substitute was shown by the loss of weight in the animals, and by the irritation of the skin which evidently was trying to eliminate some of the remaining impurities through its surface.
Modifying circumstances.
Fortunately for mankind, it has not been customary, nor even possible, to build dwellings or stables approaching the air-tightness of a fruit jar. Air has great power of penetration, particularly when in motion, and a wind will blow air through wooden walls, and even through brick walls, in considerable quantity. It is practically impossible to build window casings and door frames so that cracks do not exist, through which air may find its way. When, however, in the wintertime, storm windows have been put on, or when, as occasionally happens, to keep out drafts, strips of paper are pasted carefully around all window casings, or when rubber weather strips are nailed tight against the windows and doors, conditions are obtained which resemble the mason fruit jar, and under those conditions, a person living continuously in such a room is experimenting on himself as Professor King did with the candle.
Another reason why it is difficult to make a room an air-tight chamber is that if a stove or fire-place be in the room, a strong suction is produced through the flame, and such suction requires the entrance of outside air. It is a common experience that a fire-place in a room otherwise tight will refuse to draw and will smoke persistently until a door or window is opened, when, a supply of air being provided, the fire is made bright and active.
Fortunately, the vitiation of the air in a room is never so severe as that in an experimental chamber, and there are few examples which can be cited of men or women dying from lack of ventilation in an ordinary room. But the serious aspect of inadequate ventilation is not that it actually induces death, but that it decreases the powers and activities of the various organs of the body; that it interferes with their normal processes, that it loads up in the body an accumulation of organic matter which is normally oxidized by fresh air and which, if not oxidized, obstructs the activities of other organs of the body.
Danger of polluted air.
Unfortunately, it is not possible to detect by the physical senses that point at which the human organism suffers from insufficient ventilation. Some years ago, Dr. Angus Smith built an air-tight chamber or box in which he allowed himself to be shut up for various lengths of time in order to analyze his own sensations on breathing vitiated air. He found that, far from being disagreeable, the sensation was pleasurable, and he says, "There was unusual delight in the mere act of breathing," although he had remained in the chamber nearly two hours. On another occasion he stayed in more than two hours without apparent discomfort, although after opening the door, persons entering from the outside found the atmosphere intolerable. He placed candles in the box, which were extinguished in a hundred and fifty minutes, and a young lady, who was interested in the experiment, going into the box as the candles went out, breathed it for five minutes easily; she then became white, and could not come out without help.
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 succumb 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 prone 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 illustrates 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 anæmic 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 breathethe 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 andadequate 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.