Fig. 61.—Water-supply installation.Fig. 61.—Water-supply installation.
The soil-pipe must be well supported along the cellar wall on brackets or hung from the floor joists by short pieces of chain or band iron. Special care must be taken to support the pipe at the elbow, where it turns upward, since a length of thirty feet of this pipe, weighing three hundred pounds, has to be provided for. It is a good practice tobuild a brick pier from the cellar bottom up to and around the elbow to support it firmly in the masonry.
The joints in this drainpipe should be made with lead, ramming some oakum into the joints first and then pouring in enough lead melted to the right degree to provide an inch depth of joint. After the lead cools, it must be expanded or calked by driving the calking tool hard against it.
To prevent rain finding its way between the soil-pipe and the roof, a piece of lead is generally wrapped around the soil-pipe for a distance of twelve inches or so above the roof, and then a flat piece of lead extending out under the shingles is slipped over and soldered fast to the other lead piece.
The fixtures are connected to the iron pipe usually by lead pipe, the lead pipe being first wiped onto a brass ferrule, the ferrule being leaded into the Y branch. These Y branches are usually two inches in diameter and the lead pipe usually one and one quarter inches. Between the soil-pipe and the fixtures a trap must be provided with a water-seal of about an inch.
Trap-vents.
In city plumbing it is customary to vent traps; that is, to carry another system of pipes from the top of the trap nearest the fixture up to and through the roof. On most roofs, where modern plumbing has been installed, are seen two pipes projecting, one the soil-pipe and the other the vent-pipe, indicating the location of a bath-room below (see Fig. 61). In a single house, however, and particularly in view of experiments made recently on the subject of trap siphonage, these trap-vents seem hardly necessary.They were formerly insisted upon because of the feeling that by the passage of a large amount of water down the soil-pipe, sufficient suction might be induced to draw out the water from some small trap on the way, thereby opening a passage for sewer gas into the room. Experiments have shown that it is practically impossible to draw off the water from a trap in this way, and that the system of vent-pipes does little more than add to the cost.
The traps themselves, however, are essential, and great care should be taken to see that each trap is in place and has a seal of the depth already mentioned. The best trap to use in any fixture is the simplest, and a plain S trap answers every purpose. It is always wise to have a clean-out at the bottom of the trap; that is, a small opening which can be closed with a screw plug, so that when the trap becomes clogged, it can be easily opened and cleaned (see Fig. 62).
Fig. 62.—A trap.Fig. 62.—A trap.
Water-closets.
A great many kinds of water-closets have been made and used, with various degrees of success. The old-fashioned pan-closet becomes easily clogged, allows matter to decompose in the receptacle under the valve, and, in spite of its being cheaper, should not be used. The long-hopper closet is also objectionable, for the same reason. A recent bulletin of the Maine State Board of Health, which gives the relative merits of the different forms now available, very directly and briefly, is here repeated:—
"The choice of a water-closet should be made from thosewhich have the bowl and trap all in one piece, which are simple in construction, are self-cleansing, and have a safe water-seal. None should be considered except the short-hopper, the washout, the washdown, the syphonic, and the syphon-jet closets.
"Short-hopper closets not many years ago were considered desirable, but other styles costing but little more are better.
Fig. 63.—Washout water-closet.Fig. 63.—Washout water-closet.
"The washout closet (Fig. 63) has too shallow a pool of water to receive the soil, and the trap below and the portion above the trap do not receive a sufficient scouring from the flush.
Fig. 64.—Washdown water-closet.Fig. 64.—Washdown water-closet.
"The washdown closet (Fig. 64) is an improvement over the washout. Having a deep basin, a deep water-seal, smaller surfaces uncovered by water, and a more efficient scouring action, it is more cleanly. The washdown closet is really an improved short hopper.
Fig. 65.—Syphonic closet.Fig. 65.—Syphonic closet.
"Of late years the principle of syphonic action has been applied to the washdown closet. Figure 65 shows the outline of a syphonic closet. It will be seen that the basin, as in the washdown closet, has considerable depth and holds a considerable quantity of water; but it differs in having a more contracted outlet. When the closet is flushed, the filling of this outlet forms a syphon, and then the pressureof the air upon the surface of the water in the basin drives the water into the soil-pipe with much force. At the breaking of the syphon, enough water is left in the trap to preserve the seal.
Fig. 66.—Syphon-jet closet.Fig. 66.—Syphon-jet closet.
"In the syphon-jet closet (Fig. 66) there is added to the mechanism of the syphon closet a jet of water which helps to drive the contents of the bowl more rapidly into the outlet. These two closets, syphon and the syphon-jet, are preferable to those of any other style. Among other advantages they are more nearly noiseless than any other kinds.
"Recapitulating, it may be said, while the short-hopper and the washout closets may not deserve absolute condemnation, the advantages of the washdown, syphon, and the syphon-jet closets are so much greater that they should be chosen in all new work."
Properly to flush out the closet, a water-pipe connection must be made from the supply main. It would be quite possible to connect directly to the closet rim where the flush enters, but there are two objections urged against this. Sometimes, when the pressure is low and water is being drawn in the kitchen, if a faucet in the bath-room is opened, not only will no water come, but air is drawn into the pipe by the force of the running water below. A direct connection with a water-closet, it is conceivable, might allow filth to be drawn up into the water-pipe under certain conditions. The other objection is that the small pipe generally used in a house does not deliver water fast enough for effective flushing.
It is common, therefore, to put in, just back of or above the closet, a small copper-lined wooden tank which holds about three gallons and which can be discharged rapidly through a one-and-a-quarter-inch pipe. This tank with fittings costs about $10, and in a great many cases is probably unnecessary. It has the advantage, however, of allowing a small flow to enter the tank whenever emptied, to be automatically shut off by a float valve when filled. If the house has a tank supply or if the pressure is strong enough to insure a positive flow at all times, there can be no objection in a single family, where the flushing action will be insisted on by the mistress of the house in the interests of cleanliness, to making a direct connection between the closet and the house supply pipe. An automatic shut-off bibb would then be used on the water-pipe, allowing the water to flow freely as long as the bibb was opened, but closing automatically when released.
The subject of sewage disposal for a single house in the country does not at all present the elaborate problem that is suggested when the disposal of sewage of a city is under discussion. In the first place, the amount of sewage to be dealt with is moderate in quantity; and in the second place the area available on which the sewage may be treated is in almost all cases more than ample for the purpose. Nor is there the complication that arises with city sewage, due to the admixture of manufacturing wastes. The material to be handled is entirely domestic sewage and varies only according to the amount of water used in the house, making the sewage of greater or less strength according as less or more water is used. Sewage from a single house differs only in one respect disadvantageously from city sewage, namely, in the fact that the sewage, not having to pass through a long length of pipe, comes to the place of disposal in what is known as a fresh condition; that is, no organic changes have taken place in the material of which the sewage is composed.
Definition of sewage.
The great bulk of sewage is water, and, in quantity, the amount of sewage to be cared for is about equal to theamount of water consumed in the household, although this will depend somewhat on the habits of the family. If, for example, part of the water-supply is used for an ornamental fountain in the front yard, or if in the summer time a large amount of water is used for sprinkling the lawns, that water is not converted into sewage, and the amount of the latter is thereby diminished; but, ordinarily, it is safe to say that the quantity of water supplied to the house and the quantity of sewage taken away from the house is identical, and since it is much easier to measure the water-supply than the sewage flow, the former is taken as the quantity of sewage to be treated.
In the course of its passage through the house, however, the water has added to it a certain amount of polluting substances, largely derived from the kitchen sink, where dirt from vegetables and particles of vegetable material, together with more or less soap, are carried by the waste water from the sink into the drain. In the bath-room, also, some small amount of organic matter is added to the water, but the proportion of such matter to the total volume of water used is very small, probably not exceeding one tenth of one per cent. This small proportion is nevertheless sufficient to become very objectionable if allowed to decompose, and the problem of sewage disposal for a single house is to drain away the water, leaving behind the solids so disposed that they shall not subsequently cause offense by their putrefaction.
The process of decay is normal for all organic matter and is due to the agency of certain bacteria whose duty it is, providentially, to eliminate from the surface of the earth organic matter which otherwise would remain useless,if not destructive, to man. It is impossible to leave any vegetable or animal matter exposed to the air without this process of decay at once setting in. Apples left in the orchard at the end of the season inevitably are reduced and disappear in a short time. Dead animals, whether large or small, in the same way succumb to the same process of nature, and it has been pointed out that, unless this provision did exist, the accumulation of such organic wastes since the settlement of this country would be so great as to make the country uninhabitable. Fortunately, however, this inevitable process breaks down the structure of all organic material, partly converting fiber and pulp into gas, partly liquefying the material and converting the remainder into inorganic matter which is of vast importance as food for plant life. A cycle is thus formed which may be best illustrated in the case of cows which feed on the herbage of a meadow, the manure from the cows furnishing food for the grass which otherwise would soon exhaust the nutriment of the soil.
Stream pollution.
The first fundamental principle of sewage disposal, therefore, is to distribute the organic matter in the sewage so that these beneficent bacteria may most rapidly and thoroughly accomplish their purpose. During the last fifty years, a great deal of study has been expended on this problem, and while it has not as yet been entirely solved, certain essential features have been well established.
The most important factor promoting the activity of these agents of decay is the presence of air, since in many ways it has been proved that without air their action is impossible. Thus it has been shown that dischargingsewage into a stream, whether the stream be a slow and sluggish one or whether it be a mountain stream churned into foam by repeated waterfalls, has little other power to act on organic matter than to hold it for transportation down stream, or to allow it to settle in slower reaches until mud banks have been accumulated which will be washed out again at the first freshet. Experiments have shown that the agencies to which certain diseases are attributed, commonly known as pathogenic bacteria, are frequently, if not always, found in sewage, and that when these bacteria are discharged into streams they may be carried with the stream hundreds of miles and retain all their power for evil, in case the water is used for drinking purposes. No right-minded person to-day will so abuse the rights of his fellow-citizens as deliberately to pour into a stream such unmistakable poison as sewage has proved itself to be. The fact is so well known that it is not worth while pointing out examples. It is enough to say that some of the worst epidemics of typhoid fever which this country has known have been traced to the agency of drinking water, polluted miles away by a relatively small amount of sewage.
In a number of states, laws have been passed which expressly prohibit the discharge of sewage, even from a single house, into a stream of any sort, even though the stream is on the land of the man thus discharging sewage and where it would appear as if he alone might control the uses of that stream. Unfortunately, the machinery of the law does not always operate to detect and punish the breakers of the law, but any law which, as in this case, has so positive a reason for its existence, and violation of whichis so certain to bring disaster on persons drinking the water of the stream below the point where the sewage is discharged, any law which appeals for its enforcement so directly to the common sense and right feeling of all intelligent people, seems hardly to need legal machinery for its enforcement. It must depend, as indeed all laws must depend, upon the intelligent support of the community, and surely no law would commend itself more urgently than this one forbidding the pollution of drinking water.
In spite of the fact that the lack of air in the water will prevent bacterial action, there are, nevertheless, many cases where the discharge of sewage into a stream may be permitted as being the best solution of the disposal problem, provided always that the stream is not used and is not likely to be used for drinking water. Such cases occur where the stream is relatively large and where the level of the stream is fairly regular, so that there is no likelihood of the deposit of organic matter on the banks during the falling of the stream level. Examples of this sort might be cited in the vicinity of the Mohawk or Hudson River, or in the vicinity of any of the larger rivers of any populous state, since although the water of the Mohawk is used by the city of Albany for drinking purposes, yet the amount of organic matter which inevitably finds its way into such rivers precludes its use for drinking without filtration. Into the Hudson below Albany there can hardly be any question of the propriety of discharging sewage from a single house.
Again, houses in the vicinity of large bodies of still water may without question be allowed to discharge into thoselakes. For example, houses in the vicinity of Lake Ontario or Lake Michigan, or even of much smaller lakes, should not contribute any offensive pollution to the waters of the lake. In New York State, some of the smaller lakes are used as water-supplies for cities, as, for example, Owasco Lake for the city of Auburn and Skaneateles Lake for the city of Syracuse, and, acting under the statutes, special laws have been passed by the State Department of Health, forbidding any discharge of any kind of household wastes into these lakes. The same is done in other states. Here, again, it is a question of the drinking supply which is being considered, and not a question of the possibility of any nuisance being committed.
Treatment of sewage on land.
If no stream suitable for the reception of sewage is available, then the sewage must in some way be treated on land before it passes into the nearest watercourse. For the second fundamental principle about the treatment of sewage is that of all places the action of putrefactive bacteria is most energetic in the surface soil and that it is there that the organic matter of sewage can be most rapidly accomplished. Experiments already referred to have shown not only this, but also that their activity is most noticeable in the surface layers of the soil and that their action continues for scarcely two feet downward, and it is customary to assume that the largest amount of work done is accomplished in the top twelve inches. Further than this, it has been established that in order to persuade the bacteria involved to do their work as promptly as possible, the application of sewage to any particular locality should be made intermittent; that is, that a restingperiod should be given to the bacteria between successive applications of sewage.
For example, one can recall without difficulty the conditions on the ground at the back of the house where the kitchen sink-drain commonly discharges. At the beginning of summer perhaps a rank growth of grass starts up vigorously in the vicinity, and the path of the surface drain can be traced by the heavy vegetation along the line of the drain. If the slope of the surface away from the house is considerable, no other effect may be noticed through the season, since the surface slope carries away the sewage, spreading it out over the ground so that the soil really has a chance to breathe between successive doses. But if the ground is flat, it will be remembered that before many weeks the sewage ceases to sink into it; the ground becomes "sewage-sick," as they say in England, and a thick, dark-colored pool of sewage gradually forms, which smells abominably. If a piece of hose a dozen feet long had been attached to the end of the drain and each day shifted in position so that no particular spot received the infiltration two days in succession, it is probable that no such pondage of sewage would occur, but that the mere intermittency of the application thereby secured would permit the successful disposal of this sink waste throughout the season.
The same effect is to be noted in some cesspools where, because of the great depth to which they are dug and because no overflow into the surface layers of the soil is provided, the pores of the ground around the cesspool become clogged and choked, and the cesspool becomes filled with a thick, viscous, dark-colored, objectionable-looking, and evil-smelling liquid.
The three principles which will avoid these conditions are, as already stated, plenty of air, presence of bacteria normally found in the surface layers of the soil, and intermittency of application.
In order to secure the operation of these three principles in the application of sewage onto land, the sewage must be made to pass either over the surface of the land in its natural condition in such a way that the sewage may sink into the soil and be absorbed and at the same time give up its manurial elements to whatever vegetation the soil produces; or, as a modification of this principle, the sewage may be required to pass through an artificial bed of coarse material by which the rate of treatment may be considerably increased. In the latter case, although probably the greater part of the action of the bacteria takes place in the top twelve inches, it is customary to make the beds about three feet thick, chiefly in order to prevent uneven discharge of the sewage through the bed. Finally, wherever, for æsthetic reasons, it is desirable that the sewage should not be in evidence, either before passing through the natural soil or exposed in an artificial bed, the practice may be resorted to of distributing the sewage through agricultural tile drain laid about twelve inches below the surface. In this way, the sewage is scattered through the top soil, where bacteria are most active, without being apparent, and a front lawn thus treated would not give any indication of its use.
Taking up now in order these three methods of treatment, we may consider some of the details of construction. In spreading the sewage over the lawn or in distributing it on the surface, due regard must be paid to the kind of soil. Clay soils and peaty soils are useless for the purposeof sewage disposal unless as the result of continuous cultivation a few inches of top soil may have accumulated on the clay. This top soil is adapted to sewage purification, provided the quantity applied is not excessive.
Surface application on land.
Two methods of operation may be pointed out. The sewage (and this is the simplest method of disposal possible) may be brought to the upper edge of a small piece of ground, usually sowed to grass, and allowed merely to run out over the surface of the ground. There should be, however, some method of alternating plots of ground, one with another, so that the sewage is turned from one to the other every day. Each plot will then have one day's application of sewage and one day's rest, and this would complete the disposal, were it not for the interference of rain and cold. The winter season practically puts a stop to this method of treatment, and rainy weather reduces the power of the soil to absorb sewage. For these two reasons, it is desirable to have one plot in reserve, or three in all, and the area of each plot should be based on the amount of sewage contributed. For a family of ten persons using twenty-five gallons of water per day the total area provided should be one tenth of one acre, or an area seventy feet square divided into three plots. Figure 67 shows six beds arranged to care for the sewage of a public institution in Massachusetts. As a guide to the amount of land needed, it will be safe to provide at the rate of one acre for each forty persons where the soil is a well-worked loam but underlaid with clay. The effect of this irrigation on the grass will be to induce a heavy, rank growth which must be kept down by repeated cutting or by constant grazing. Bothmethods are practiced in England, and it may be said in passing that no injury to stock from the feeding of such sewage-grown grass has been recorded. The grass cut from such areas (and the cutting is done every two weeks through the whole summer) is packed into silos and fed to cattle through the winter with advantage. Or, if grazing is resorted to to keep the grass down, the herd is alternated with the sewage from one field to the other, so that the bed which has received sewage one week is used for pasture the next week, and the number of head which can thus be fed is astonishing. In order to secure an even flow of sewage over such grass land as is here contemplated, there must be a gentle slope to the field, and the ditch or drain bringing the sewage to the field should run along its upper side. Openings from the drain, controlled by simple stop planks, are provided at intervals of about ten feet, and no attention is needed further than the opening and closing of these admission gates.
Fig. 67.—Sewage beds.Fig. 67.—Sewage beds.
Another method of applying sewage to the surface of the ground is to lead it in channels between narrow beds on which vegetables have grown. These beds are made about eight feet wide with two rows of root crops, such as turnips or beets, set back about two feet from the edge. The beds are made by properly plowing, the channels between the beds being back-furrowed. Here, again, the principle of intermittent application is essential, and the area to be provided is the same as already given for the surface irrigation. Three beds should be provided, as before; but, in general, no provision need be made for carrying off the sewage at the lower end of the beds, since it may be safely assumed that all of the sewage will be absorbedby the soil. Of course, a sandy soil will absorb more water than a clay soil, and if the soil is entirely clay, it is not suitable for such treatment. Sewage passed over the surface of clay soil, however, will, in the course of a few months, so modify the clay as to convert it into a loam, and in this way increase its absorptive power.
When possible, it is desirable to have a plot of plowed ground over which the sewage may pass before reaching the beds, so that the grosser impurities may be left behind and harrowed in or plowed under. If proper regard is paid to intermittent application, no danger from odors need be feared, and the repeated plowing in will increase immensely the fertility of the soil. Nor need one be afraid that all of the manurial elements will be left behind on this plowed ground. About two thirds of the organic matter in sewage is in solution, and this will be carried onto the beds just as if passage over the plowed ground had not occurred.
Artificial sewage beds.
In order to secure a higher rate of discharge of sewage through the soil it is best to arrange an artificial bed which shall be made of coarse, sandy material which will allow a rate of at least 10 times that already given. The best material out of which to make such an artificial bed is a coarse sand; that is, a sand whose particles will not pass through a sieve which has 60 meshes to the inch and which would pass through a sieve of 10 meshes to the inch. Such an ideal sand will purify sewage at the rate of 50,000 gallons per acre per day, or an acre will take care of the sewage of at least 1000 persons. This means that it is necessary to provide about 50 square feet for each personin the family, or a family of 10 persons could have all the sewage taken care of on an area 25 feet square. The same principle of intermittency of application, however, must be observed by dividing the bed into three parts, so that the sewage may be alternated from one bed to another. Practice has indicated that it is better to shift from bed to bed about once a week and to deliver the sewage onto each bed intermittently; that is, to discharge a bucketful at a time with short intervals between, rather than to allow a small stream to flow continuously onto a bed. Such a bed should be about 3 feet deep, as already stated, and preferably should have light concrete side walls and bottom, as shown in the sketch (Fig. 68). Ordinarily, the surface of the sand will be level, and the dose of sewage applied to the bed will cover it a fraction of an inch deep, and in the course of an hour or so will disappear into the sand and reappear in the underdrains as clear water.
Fig. 68.—Sewage beds.Fig. 68.—Sewage beds.
In cold weather a thin sheet of sewage spread out over the surface of the sand would freeze before penetrating the bed; therefore, in the winter time, it is usual to furrow the beds; that is, dig furrows across the beds 2 or 3 inches wide at the bottom and about 10 inches deep, so that in the bottom of these furrows the sewage may be, partly at least, protected against frost. It has been found that, if sewage is discharged intermittently,—that is, in bucketfuls into such furrows,—the beds open and allow the filtration of the sewage. To be sure, the purification effected in cold weather is not quite that accomplished in warm weather, but the results are sufficiently satisfactory, and no nuisance ensues.
Subsurface tile disposal.
The other method of distributing sewage over land is by means of draintile placed in shallow trenches, so that the sewage may leach out into the soil through the open joints of the pipe. These draintiles receive the sewage intermittently, and by the constant rush of water are presumably filled throughout their length. The sewage then gradually works out of the joints into the surrounding soil, and the pipes are empty and ready to receive another dose when next delivered.
Two essential points must be considered in the successful operation of such a plant: the grade of the tile and the length of the tile.
The grade of the tile must be properly adjusted to the porosity of the soil; that is, in open, porous, and gravelly soils a grade must be steeper than in loamy and dense soils. The reason is manifest. In a gravel soil, the sewage is at first rapidly absorbed, so that as the sewage goes down the pipe line the first joints take up the water and deliver it to the soil, where it disappears, and probably no flow reaches the end of the line at all. This means that the soil surrounding the first joints does the work which the entire pipe line was intended to do and thus becomes overworked. When overworked, the soil always refuses to do anything, so that when the succeeding joints take up the sewage and in their turn become overworked, the line is useless. If, on the other hand, the grade had been steep enough to carry the sewage down the pipe line gradually so as to secure a uniform distribution, then the same or approximately the same amount of sewage would be taken out of the pipe at each joint, securing a long life for the system. In loamy soil, on the contrary, there is not the same absorption at the joints, and so on a steep grade there is the tendency for all the sewage to follow down the pipe line to the lower end and there escape to clog the soil and thus spoil the system. As a general average, it may be said that the proper grade for such a subsurface distribution pipe line in a fairly good sandy loam should be 5 inches in 100 feet; less than this as the loam becomes clay and more as the loam becomes gravel.
The other essential point for the successful operationof this method of distribution is to provide a proper length of pipe for the number of persons contributing sewage. The soil itself will absorb about the same amount as when the sewage is spread over the surface, so that a family of ten persons would require, as before, an area about 70 feet square. The pipe lines may be laid in different sections, provided the different lines of pipe are not nearer together than 10 feet. On an area 70 feet square there would be, therefore, 7 lines of pipe each 70 feet long, or 490 lineal feet of pipe in all, or 49 feet per person. The writer generally allows 40 feet in well-cultivated soil as a reasonable length of pipe for each person in the family. If the soil is sandy, this may be reduced one half, but need not be increased under any conditions, since a soil requiring a greater length of pipe than 40 feet per person would be so dense as to be unfit for use. To properly arrange the lines of pipe on a sloping ground requires careful study of the inclination of the ground and of the relation of direction of lines of pipe to slope. Usually the slope of the ground is greater than the 5 inches per 100 feet just referred to, but by laying out the lines of pipe across the slope instead of with it any grade desired may be obtained. Nor is it necessary that these lines of draintile be run in straight lines; they may very properly follow the curving slope, the proper grade being always carefully maintained.
Fig. 69.—Plan of subsurface irrigation field.Fig. 69.—Plan of subsurface irrigation field.
Common agricultural tiles three inches in diameter and costing about two cents per running foot are suitable material for these distribution lines. The sewage enters these distribution lines from a larger pipe, usually six inches in diameter, and a difficult adjustment is presented that each branch tile line shall receive its own proportionate share of the sewage. If only one line of tile is provided, say 200 feet long for 5 members in the family, then all the sewage goes into that line with no question of distribution arising, but if a number of short parallel lines must be used, as shown in the sketch (Fig. 69), the difficulty of subdividing the sewage properly among the different branch lines becomes very great. For that reason the writer prefers to use not more than two lines, with thepossibility of delivering the sewage alternately in the one and the other. In this way, the bed not receiving sewage is resting, while the other bed is acting, and also the outlet for the sewage is always definitely known. And particularly in the case of these subsurface tile, the necessity for the intermittent dosing is apparent, since with small, constant trickling discharges the difficulty of distribution through the long length of tile is gradually increased, and usually saturation of the soil occurs from joint to joint, as already described. Therefore it becomes most necessary, in this case, for the best results on the soil not merely to alternate the beds receiving sewage, but also to effect the intermittent discharge onto the beds or through the pipes although the sewage itself may flow very uniformly in volume.
Automatic syphon.
This intermittent discharge is accomplished by constructing on the pipe line from the house and before it reaches the beds an "automatic syphon," as it is called, the operation of which may be described as follows: As the sewage enters the tank containing the syphon and rises outside the syphon-bell, air is compressed between the water surface inside the bell and the water left inside the syphon-leg. With greater and greater height of water outside, this compression inside becomes greater and forces the water in the syphon-leg lower and lower. Finally, the water sinks so low as to allow the compressed air to escape suddenly around this bend, instantly relieving the compression, and the water outside rushing in to fill up the space occupied by the air starts the syphon (see Fig. 70).
Fig. 70.—Section of "Miller" syphon.Fig. 70.—Section of "Miller" syphon.
This syphon, in size suitable for a single house, costs about $12 delivered, and will always be available to secure an intermittent dosing of the bed or pipe line. Usually the chamber in which this syphon is placed holds about one hour's flow, so that it may be estimated that this syphon will discharge on the bed every sixty minutes. The exact interval of time is not essential nor, perhaps, important, although it may be noted that the coarser the material,—that is, the nearer uniform all the sand particles are to the largest size passing the ten-mesh size,—the smaller must be the dose applied, but the more frequentlymust the application be made. This has been very thoroughly studied in Massachusetts, and the views of experts on this subject may be found in the report of that Board.
Such an intermittent discharge may be made and often is made by a hand valve leading out from this chamber in institutions or in private houses where some one constantly is available for the purpose. Thus it becomes the duty of the man in charge every hour or perhaps three times a day to pull the valve and allow the sewage to discharge (see Fig. 71). An overflow pipe should always be provided, so that if he forgets to pull the valve, the sewage will still find its way into the system rather than out on the ground.
Fig. 71.—Plan and section of a septic tank with valve.Fig. 71.—Plan and section of a septic tank with valve.
Sedimentation.
As a matter of economy of operation, it has been found desirable to take out from the sewage before the treatment already described as much of the solid matter as may be reasonably done, and for this purpose sedimentation is made use of. Most of the solids in sewage are slightly heavier than water, so that if they be allowed to stand in the water for a short length oftime, they will settle to the bottom of the tank and allow the liquid above to pass on, considerably clarified. It has been found worth while to do this, since all three processes described are interfered with if the solids taken out by sedimentation are allowed to be deposited either upon the surface of the ground, giving rise to odors as well as to objectionable appearances, or onto the surface of the sand beds, which they clog up, or in the three-inch tile drain, which may be filled in a short time.
It has been further found by experience that if these sedimentation tanks are made large, really larger than necessary for sedimentation, in some way a large proportion of the matter accumulating in the tank will disappear, so that the amount of sediment to be taken out of the tank is not as large as might be expected. In fact it is usual for such tanks to run one or two years without cleaning, although the amount of solids shown by chemical analysis to have been removed from the sewage would fill the tank twice over.
It has been found that a tank, in order to do successful work in separating solids and in eliminating as much as possible of the sediment, needs to be of a capacity to equal about one day's flow of the sewage, and this is a good basis for computation. Here, again, the fact that the sewage from a single house is considerably fresher than the sewage from a city must be remembered, since, while many cities build tanks holding only one third or one fourth of their daily flow with good results, in the case of a single house this is not possible, and the tanks, if built at all, ought to hold at least the full day's flow. Ten persons, at 25 gallons each, furnish 250 gallons per day or 33 cubicfeet. The tank, then, must be large enough to hold this volume, and suitable proportions generally require that the tank be at least 5 times as long as wide. A certain allowance must always be made for deposit in the bottom and for the accumulation of scum on the top, so that an extra foot or more of depth is desirable. The tank, then, to furnish the required 33 feet, might be made 3 feet wide, 3 feet deep, and 5 feet long, and probably in no case would a tank much smaller than this be used.
Fig 72.—Section of a septic tank with syphon chamber.Fig 72.—Section of a septic tank with syphon chamber.
There are two or three details of tank construction which may be suggested, although almost any kind of tank will answer the purpose. It is desirable in order that the surface scum may not be disturbed, and in order that the inflowing sewage may distribute itself as uniformly as possible across the tank, to attach an elbow to the entering pipe so that the sewage enters about halfway between the top and bottom of the tank (see Fig. 72). Similarly, at the outlet or weir an elbow should be provided because it is not desirable to allow the floating matter of the surface to be carried onto the bed, and a pipe taking off liquid, open halfway between top and bottom, will carry away but little of either the surface scum or bottom sediment. Such a tank must be built of concrete or masonry or timber, although the latter is notto be recommended because of its short life. The walls of an ordinary tank may be built 6 inches thick at the top and 12 inches to 18 inches thick at the bottom, the latter being necessary if the depth is over 8 feet. The tank should have 6 inches of concrete on the bottom, and the roof may be made of flagstone or of concrete slabs in which some wire mesh has been buried.
It is not necessary to ventilate this tank, although it is desirable to have perhaps a foot of air-space between the water level and the roof of the tank. During the first few months of its operation such a tank is very likely to smell badly, and, if ventilators are provided, the presence of the tank will be well known by the odors sent off. After the tank has been in operation two or three months these odors gradually disappear, due presumably to the fact that the surface of the water in the tank has become coated with a thick blanket through which odors cannot penetrate. On the other hand, there have been a few cases recorded where the production of gas in a septic tank was so great that an explosion occurred, tearing off the roof and otherwise doing considerable damage.
The full plant, therefore, will consist of the settling tank, receiving the raw sewage from the house and discharging it into a small tank holding about one hour's flow and containing the automatic syphon apparatus for intermittent discharge. This dosing tank must provide for one hour's flow at the maximum rate of flow, and should hold about one fourth of the total daily flow. Then the ground area, either natural or artificial, which receives the intermittent discharge from the dosing tank, completes the installation (see Fig. 73).
Fig. 73.—Plan of sewage disposal for single house with details of receiving tank.Fig. 73.—Plan of sewage disposal for single house with details of receiving tank.
Underdrains.
The question of installing underdrains will arise only in cases where the ground water, always to be found below the surface somewhere, comes up so high as to affect the disposal of sewage. Usually no underdrains will be needed unless the ground water gets up to within three feet of the surface, and, in a number of cases, underdrains have been laid under a sewage filter at considerable expense, only to find when the filter was in operation that they were never in use. In clay soils the underdrain is not necessary. In fact, it may be noticed that the underdrain is not for the purpose of taking care of the sewage, but rather of draining off the soil-water and preventing its interferencewith the action of soil on sewage. This principle will indicate where underdrains are necessary and where not.
When used, underdrains should be laid from three to four feet below the surface in parallel lines about fifteen feet apart and on grades of not less than one foot in one hundred. It is always better to have the underdrains too large than too small, and drains less than three inches in diameter should not be used, and they should increase in size to four inches and then to six inches as the separate drains are brought together. The writer has seen a six-inch underdrain running full of ground water collected within a distance of a hundred feet, but this was in gravel soil through which the water passed very freely. No exact rules can be given for the size of the underdrains, but it will be noticed that, since water passes through clay soil slowly and through gravel soil rapidly, larger pipes must be used where the soil is coarse.
Milk has long been considered to be one of the most important human foods, particularly for the young, combining within itself all the essential elements necessary for the production of cell tissue and for animal vitality. In composition, it is about 87 per cent water, the remaining 13 per cent being divided between fat, casein, and sugar in equal parts, with a small addition of salt.
As is well known, milk is the sole food upon which it is possible to sustain life for long periods, and while this applies directly to infants, it is by no means confined to them. Many examples can be given of men and women of mature life who, either on account of some digestive disorder or some mental bias, have confined themselves absolutely to a diet of about two quarts of milk a day and have lived thereon for months and years without suffering from lack of nutrition.
In recent years, due to the advocacy of the eminent scientist, Metchnikoff, who asserts that researches in the Pasteur Institute have shown that certain diseases of advanced age are due to auto-intoxication from the largerintestine and that the consumption of fermented milk acts as an antiseptic, neutralizing this bacterial intoxication, the consumption of fermented milk, or buttermilk, or koumiss, has very largely increased. It is, in fact, rather remarkable to find that in large cities, business men whose digestions have been ruined are devoting themselves to unlimited quantities of buttermilk in the hope that their former excesses and absurdities in the way of food may be counteracted and health restored.
Between these two extremes—the use of milk for the very young and for the aged and infirm—milk plays an important part as food. The consumption of milk in New York State, according to statistics, amounts to about a pint a day for each person for that part of the country. As an article of food, milk has the advantage already referred to, namely, that besides its nutritive power it has a curative effect greatly augmented by fermentation, the modification so vigorously advocated by Metchnikoff. Another advantage which milk possesses as an article of food is that, by sterilization and storage in closed vessels, it may be kept for days and even months in good condition. At the time of the Paris Exposition, milk was sent from America and exhibited alongside of French milk with no preservatives except heat used for removing the bacteria in the milk and then cold storage for keeping others out, and two weeks after the original bottling the milk was in good condition. To meet the need of ailing babies, advantage was taken of this valuable property of milk, by which it could be shipped from dairies near New York to the Isthmus of Panama, and used continually with good results although more than a week old.
Bacteria in milk.
The great disadvantage which milk sustains as an article of food is that the same composition that makes it so useful as a diet for man, also renders it a most admirable culture medium for the rapid development of all kinds of bacteria. Some of these bacteria are, without doubt, benign in their effect upon man; as, for example, the particular species used to produce koumiss and other varieties of fermented milk now recommended by physicians. But there are many other kinds of bacteria that find life in milk congenial, whose effect upon the human system is not salutary, and, if milk infected with those varieties is used for feeding infants, the result is quite likely to be a disturbance of their digestive system, producing diarrhea and cholera infantum and possibly death.
It was at one time common to add to milk certain antiseptics for the purpose of preventing the growth of bacteria, and, except that the preservatives acted quite as injuriously upon man as upon the bacteria, the results, so far as merely keeping the milk went, were all that could be desired. The chemicals added were borax, boracic acid, salicilic acid, sodium carbonate, and other similar disinfectants. Gradually, however, it has come to be known that, inasmuch as the milk when first drawn from the cow's udder is sterile, that is, contains no bacteria, and since it is quite possible to prevent the introduction of bacteria into milk during the processes of milking, straining, and bottling, there is no need of the addition of preservatives, provided particular care is exercised in handling the milk.
Effects of bacteria.
Since this care involves the expenditure of both additionaltime and money, questions at once arise whether such expenditure is necessary, whether the introduction of a few bacteria into the milk is objectionable, and what the results are upon the persons drinking milk containing bacteria. For our present purpose, the kinds of bacteria which find their way into milk may be divided into two classes, namely, those that are normally in milk and which tend to produce souring, and those which accidentally enter and are able to produce disease in persons drinking the milk. The first kind probably enter the milk from the air or from the surface of the milk-pail, and in the milk increase in numbers very rapidly and have the same effect in the milk and on persons drinking the milk as any large amount of organic matter.
The second kind of bacteria are known as pathogenic; that is, are the direct cause of disease when taken into the human system. Under ordinary circumstances, this latter class will not be found in milk, since these kinds of bacteria must come from some infected person, and if no such person is in contact with the milk at any stage, then it is impossible for the milk to become so polluted. However, those interested in preventing the spread of disease through polluted milk argue that if the conditions in a stable and dairy are so unclean that large numbers of the normal milk bacteria can enter the milk and increase in numbers there, then conditions would be favorable for the introduction of pathogenic bacteria whenever the milker or bottle-washer or the strainer or any of the helpers became sick.
To show the difference in the effect of a clean stable and dairy as compared with an ordinary one, it is only necessary to say that in investigating the quality of themilk supply of a certain city recently, the writer found one stable where the milk analyses showed from half a million to a million bacteria per c.c.,[2]—that is, per half-teaspoonful,—and this was occurring in the dairy regularly from month to month as the analyses were made. Another stable in the same city showed just as regularly a bacterial count in the milk of from 1000 to 5000 per c.c., the difference being due solely to the way in which the stables and dairies were kept,—in the one case with no regard to cleanliness and in the other with the very best attention paid thereto. Certainly, if dirt is so much in evidence that a million bacteria can enter the milk in every c.c., no particular pains can be taken in such a stable to keep out disease germs; while in the clean stable, where so few germs enter, disease germs could hardly find any opportunity for lodgment.
The following example may be given to indicate the effect of impure milk upon a community. The vital statistics of the city of Rochester, including the deaths of children under five years, show that from 1889 to 1896, during the summer, infants died at the rate of 109 per 100,000 population. The health officer of the city undertook to improve the quality of the milk, and from 1896 to 1905, statistics show that the number of children dying, under five years, was only at the rate of 54 per 100,000,—a manifest saving due, without doubt, to the improvement in the quality of the milk. By repeated examinations of the dairies, by rigid enforcement of certain rules governing the distribution of milk, and by detailed lessons tomothers in the tenement-house districts on the care of milk, the quality of the milk was so improved as to make the reduction in the death-rate already pointed out.
The Honorable Nathan Strauss, of New York City, has taken up the same idea, and, by supplying the poor with milk properly heated so as to destroy the bacteria which may have been introduced by careless handling, has also saved hundreds of thousands of children from premature death.
Diseases caused by milk.
Many infectious diseases are propagated by milk, not only among children, whose chief food is found in this supply, but also among those of more mature age who, though drinking only a small quantity, are apparently more easily affected. Four diseases are particularly to be noted in connection with the consumption of milk, namely, typhoid fever, scarlet fever, diphtheria, and tuberculosis.
Typhoid fever from milk.
One of the most striking illustrations of the spread of typhoid fever through milk occurred this last year in the city of Ithaca, New York. The city proper lies in a valley between two hills, the milkmen having their farms on both sides of the valley to the east and west, on the hill slopes. One milkman on the west, with a large route, delivered his own milk only in part and bought an additional supply from a farmer on the east. In the family of the latter occurred a case of typhoid fever in September, pronounced by the local physician to be sunstroke, but evidently typhoid fever, since other cases of secondary infection developed in the same family and were then pronounced typhoid. The milk from this east-side farmwas taken down the hillside and turned over to the west-side farmer, who distributed his own milk in his trip from his farm across the valley, his route being so timed as to allow him thus to dispose of all his own milk. Having then loaded up with the east-side supply, he started back across the valley, distributing the milk which was evidently polluted, since on his return route house after house developed typhoid fever, with no cases on the first part of the route and with no other cases in town except those on this milk route. Forty-four cases developed in all, with two deaths.
The Reports of the Massachusetts State Board of Health give a number of cases of the same sort, all showing that milk is easily infected by persons suffering from even mild attacks of typhoid fever, attacks so slight as perhaps not to be recognized or to be worth submitting to a physician, but which are responsible for bacteria passing from the hands or mouth to a can cover or ladle, and so to the milk.
Diphtheria.
Diphtheria seems to be well established as a disease transmissible by milk, although its occurrence is not so frequent as that of typhoid fever. Not long since, the writer was much interested in an epidemic of this sort described by a physician who was convinced that the bacteria responsible for the mild form of the disease occurred largely in the nose and throat passages. He noted that as the result of these growths a constant exudation from both passages was present, and that a man with this disease, working over the milk, might easily allow the milk to be polluted by this exudate dropping from his nose.
The result was a general distribution of a mild form of diphtheria among those using the milk.
Scarlet fever.
Many examples have also been given of the distribution of scarlet fever through the agency of milk, the specific contagion probably being discharged by the patient from his nostrils, mouth, or from the dry particles of skin so characteristic of this disease. Unfortunately, mild cases of scarlatina are very apt to occur, so mild that a physician is not called in, and the only positive proof of the disease consists in the subsequent "peeling," although the nasal passages may have been alive with germs.
Tuberculosis.
So far as tuberculosis is concerned, nothing seems to be definitely proved. There is little fear of milk becoming infected from tuberculous patients or of the disease being transmitted through milk from one person to another, as with the three other diseases mentioned. The possibility of infection here lies in the fact that a cow, like man, is susceptible to tuberculosis as a disease, and undergoes the same course of prolonged suffering and death. The interesting question is whether the disease may be transmitted from a cow to a man through the cow's milk. With all the refinements suggested by science as to the virulence of the disease thus transmitted, with a study of the comparative symptoms of the two diseases, of the progress of the disease in the cow when the germs are found in the milk, and of the possibility of eliminating these germs by heating or otherwise, the danger from diseased cows is still unsettled.
So far as present knowledge goes, it is probably conservativeto say that although tests made on cows by inoculation with tuberculin show that a large proportion of the animals in the various dairy herds are more or less affected by tuberculosis, yet only a small proportion of the milk from such cows shows the presence of the tuberculosis bacillus. So far as statistics can be given on this subject, it seems probable that not more than ten per cent of the cows reacting under the tuberculin test would show tubercular bacilli in the milk, or would develop tubercular reactions if the milk were used in inoculations. The reason for this is probably that the tubercular growth in the cow does not naturally attack the milk glands until the disease is well advanced, and when the general appearance of the cow indicates severe illness, so that any careful milkman would not use the particular milk, even if the milk flow did not cease. It is not reasonable to assume that all milk from tubercular cows is itself infected, nor yet that all children drinking milk so infected will contract the disease. But the mere possibility of demonstrating that a small percentage of tubercular cows will cause human tuberculosis is sufficient to justify all possible precautions against tubercular animals and against the distribution of tubercular milk. In this connection it is worth while noting that the cows most affected by tuberculosis are those confined in small crowded stables, with no fresh air, with no exercise, and with insufficient or improper food. Unfortunately it is not possible to trace the connection between the particular animal responsible for the disease in a human being, since the period required for the development of the disease is so great that the possible time of onset is forgotten and the cause of the disease entirely out of mind.
It can only be said, therefore, that laboratory experiments have demonstrated the presence of the tuberculosis bacillus in milk from tubercular cows, and that this bacillus is known to produce tubercular lesions in man. It is wise, therefore, to eliminate the milk of tubercular cows if healthy milk is to be provided.
Methods of obtaining clean milk.
Aside from the infection of milk by specific disease-producing bacteria, the milkman of to-day must be very careful to avoid a milk which shall contain large numbers of bacteria of any type which, while not producing any specific disease, nevertheless causes changes in the chemical composition of the milk, which make it at the same time unfit as an article of food for individuals and shows the possibility of other kinds of infection.
There are two axioms to be followed if good clean milk is to be produced, and those are that the milking and straining shall be done in clean stables, from clean cows, by clean persons; and the other that the milk shall be cooled to a temperature of fifty degrees or less as soon as received from the cow. Neither of these requirements is difficult to attain, but they constitute the sole reason why some milk contains a million or more bacteria and other milk less than a thousand; and it is quite possible by enforcing these two requirements to change the number of bacteria in milk from the large figure to the small one.
Probably it is in the stable where the cows are milked that the most important factor in producing large numbers of bacteria is to be found. Not long ago the writer saw a number of stables, the ceilings of which were poles on which the winter supply of hay was stored and the atmospherewas noticeably dust-laden. A good milk could not be furnished from such a stable, and therefore it may be set down as the first requirement that the ceiling of the stable should be entirely dust-tight. Some of the best stables in the country for this reason have no loft of any sort above the cattle, but if the ceiling is tight,—that is, made with tongue-and-groove boards and then painted,—there can be no objection to the storage of hay in the loft. Hay should not be taken from the loft or fed to the cows just before milking, because the very moving of a forkful of hay through the air of the stable stirs up so large a number of bacteria in the air that quantities of them will later fall into the milk-pail.
Light and airin a stable are both important, not so much for the quality of the milk as for the health of the cows that furnish the milk. Ventilation and sunlight are both excellent antiseptics. The ordinary rule for the amount of window area per cow as given by the United States Department of Agriculture is four square feet of window surface. But it is not easy to definitely state any fixed amount of window area, since the value of the window is in its disinfecting power on the bacterial life of the stable, and this is greater or less as the windows receive the direct sunlight or are hidden under eaves where no sunlight reaches them.
The next factor in the production of good milk is the condition of thewalls of the stable. Like the ceiling, they should be absolutely free from dust, and should be smooth, so that they may be brushed or even washed clean. For this reason, walls with ledges are objectionable, and all horizontal surfaces in a stable are undesirable. Tongue-and-groovesheeting should never be laid horizontally, but rather vertically, and a smooth brick or concrete wall is better than wood in any case. The same care must be taken to have the floor clean and dry. A floor of saturated wood, containing millions of bacteria which are stirred up by the milker moving around, causes many of those millions to be deposited in the milk-pail. A concrete floor for the stalls and drains is the ideal construction, and both should be thoroughly cleaned morning and night, so that no dried refuse may remain as the living place for bacteria. Nor should the manure thrown from the stalls be left in the vicinity of the barn, but carried away at least 200 feet, in order that the barnyard may be kept dry and clean, that no smell from the manure may reach the milk, and that the flies which come from manure piles may be kept at least that distance from the cows.
The next factor in the production of clean milk is thecondition of the cow herself, not in the matter of her actual health, but in the matter of the cleanliness of her skin at the time the milking is done. If the udder and sides of the cow have been coated with manure, it is certain that more or less will fall into the milk-pail at the time of milking, and the "cowy taste" of the milk is easily accounted for in this way. In a modern stable, the milkman is careful to clean the cow ten or fifteen minutes before the milking is done by sponging or washing her belly, sides, and udder with a damp cloth or with a cloth moistened with a disinfecting solution. In one set of experiments, for instance, 20,000 bacteria per c.c. were found in the milk when the cow was rubbed off before the milking and 170,000 when the preliminary cleaning was omitted. In another case,milk from four dirty cows gave an average of 90,000 bacteria, while other cows of the same herd, milked by the same man, but carefully cleaned before milking, gave only 2000 per c.c. The care involved brings its own reward, and it is in most cases a lack of knowledge or an indifference to results which causes the malign effects above noted.
Only a few weeks ago, the writer watched the hired man start the milking and was disgusted to see the old-fashioned practice followed of squeezing a little milk onto the man's filthy hands and then the handful of milk rubbed around on the cow's teats to drip filthy and bacteria-laden into the milk-pail along with the milk itself.
One other factor is involved which, while scoffed at by some of the old-time farmers, has nevertheless proved its value, and that is the use of thenarrow-topped milk-pail. It is startling when tested by bacterial growths under the two conditions to see how many more bacteria will be found in the wide open pail than in the narrow-topped one, and while, of course, some milkers may not be able to use a pail the top of which is only six inches in diameter, it is quite worth while for milkers who do not know how to use a narrow-topped pail to learn.
The size of the opening is not the whole consideration in the matter of the milk-pail. The way it is washed is even more important. If it is merely rinsed out in cold water and then washed in warm water, it is far from clean, and milk poured into such a pail and then poured out will by that process have gathered to itself thousands of bacteria. For example, some experiments have shown that milk in well-washed pails had, on the average, 28,600bacteria per c.c., while that collected in pails of the same sort under identical conditions, except that the pails had been steamed, contained only 1300 bacteria per c.c.
Perhaps the most important factor in the care of these utensils is the necessity of killing the bacteria left in them by the milk itself. Ordinary washing will not do this. Either the washing must be done with some sterilizing agent, like strong salsoda, which must then, of course, be thoroughly rinsed out, or else the inside of the pail must be filled with absolutely boiling water or with steam. The advantage of the latter is that no contamination is possible by the water itself, whereas in washing out the disinfectant the water, unless pure, contaminates the surface again. To show the effects of clean pails, an experiment was made in which milk was drawn from a cow and found to have 6000 bacteria per c.c. It was then poured rapidly from one to another of six other apparently clean pails. At the end of the sixth pouring, the milk was found to be so changed that the number of bacteria had increased to 98,000 per c.c.
The strainer for a milk-pail is preferably made of cheesecloth, since this can always be easily boiled between milkings, and so sterilized. A wire strainer through which the milk has to pass, and where the milk is often stirred by the finger of the milker to make it pass through more rapidly, is in no sense as satisfactory as cheesecloth.
The straining should be performed as soon as each pail is filled with milk, and pails of milk should never be allowed to stand around in the barn back of the cows, but rather should be taken at once to the milk-room, where it can be strained before any further contamination takes place.
Then the milk should be cooled, and this, to be effective, must be done in such a way that the temperature of the milk shall at once fall to fifty degrees or less. It is well known that a forty-quart can of milk lowered into spring water cools slowly on the outside, but that hours will pass before the inside of the can has its temperature lowered appreciably. Meanwhile, bacterial growth has started, and that milk can never be as good as when cooled quickly throughout. Special apparatus is made in which the milk is spread out in very thin sheets over a surface cooled by ice or cold water to a low temperature. In this way all the milk is at once lowered in temperature and may then be kept in spring water until time for shipment. Many examples can be given of the value of this kind of cooling. A few years ago, the Cornell University Agricultural Experiment Station determined that a certain milk when fresh contained, about 4000 bacteria per c.c., and fifteen hours later at room temperature had 270,000, and twenty-seven hours later had soured with an innumerable number of bacteria. Another part of the same milk, however, kept at fifty degrees Fahrenheit, showed absolutely no increase in bacteria for twenty-seven hours, and was still sweet with only 12,000 bacteria at the end of three days.
City milk.
The value of pure milk is not a matter of individual opinion on the part of the farmer, but it is a vital point with thousands and millions who are dependent upon the farmer for this life-giving food. Unfortunately, to-day the relation between the consumer and the milkman is so remote that it is almost lost sight of, and in place of the personal relationship which formerly existed, which madethe milkman proud of his milk and the consumer proud of her milkman, there is to-day an absolute disregard of the interests of the other side in almost all cases. Even in the smaller cities, consolidated milk companies are being established by which the former independent milkmen are bringing milk to the central station in large cans, where it is dumped into vats along with the milk from a dozen other milkmen. Some may be good and some bad, but what is the use, each one says, of my taking particular pains when my neighbor produces milk of such poor quality? The result is that it is all far from good and likely to deteriorate rather than to improve. To be sure, at the central station it is bottled and distributed to the consumer in apparently clean glass jars, but this is not the same cleanliness that one gets when the bottling is done five minutes after the milk comes from the cow.
When the milk supplied to the larger cities is furnished as in New York, the impossibility of controlling the quality of the supply becomes apparent. The farmer brings to the shipping station his two or three large cans of milk, representing the night's and morning's milkings. These are loaded on a train along with hundreds of others, a few chunks of ice are thrown on top, and the train is started for New York, from points as far as two hundred and fifty miles away, reaching the city in the early evening. There it is received and hauled to milk stations, where it is distributed in different-sized cans and bottles, and the next morning, thirty-six hours old, distributed to the babies of the city as fresh milk. Thanks to the energetic inspection practiced by the officers of the Department of Health of New York City, who have emptied hundreds of quarts of milkinto the city gutters merely because the temperature of the milk was higher than that prescribed, the quality of the milk is not so bad as it might be. In fact, the writer has bought apparently good milk on Long Island, shipped down from New York City, because the local supply was deficient in quantity and inferior in quality, although the latter would naturally be supposed to be fresh and the other was certainly forty-eight hours old on its receipt.