man, remarked that he "had noticed many cases of consumption among these slate-workers, and that very few men can work at it long without consumption showing itself."

WATER-CLOSETS.

A very few words will enable us to dispose of this subject. Proper regulations in this particular are the exception rather than the rule. In country mills the principal defects consist of wretched construction, failure to empty the vaults until they become an overflowing, offensive nuisance, too great a istance from the mill, too near the supply of drinking water, and an abominable tom of constructing them over running streams, entailing untold evils to dwellers,rther down the stream.

In town facies, the evils lie principally in imperfect flushing, defective trapping, uncleanlines and want of proper privacy. The importance of this matter is very great, and sms to be fully recognized by the State inspectors.

REMETES Suggested.

Now for the conclusion of the mater. Where window ventilation is the only means obtainable, let it be the duty of some one person to preserve an equable temperature by frequent reference to reliable thermometers suitably placed about the rooms.

Let the ventilation be secured by lowering the top sash but slightly on the windward side, and further upon the sheltered side of the mill.

Have the room thoroughly aired during the dinner hour, and if possible, provide a separate room, free from dust, where dinner may be eaten by those who cannot get to their homes.

Have the windows, side walls and ceilings regularly and systematically cleaned.

Widen the application of the exhaust fans by applying them to other machinery than that in the picker-room.

The ideal mill of the future will be heated and ventilated by the forcible introduction of air, heated to the required temperature by being passed over

steam coils.

Provide sanitary closets, either dry earth or flushing closets, separate and distinct from the mill buildings, and yet within a convenient distance.

And, lastly, provide suitable receptacles for sputum and saliva, which, under present arrangements, find lodgment upon the floor, and when dried, enters the air, and when tuberculous in character, endangers the health of all exposed to its influence.

The Purification of Water Supplies.*

BY C. W. CHANCELLOR, M.D.,

Secretary of the State Board of Health of Maryland.

THE subject of the purification of water, which I propose to consider in many of its details, is one of very general importance-for, next to atmospheric air, water is the first necessity of living beings.

ANCIENT AND MODERN WATER SUPPLIES.

The skill and taste of the ancients in architecture, and their knowledge of mechanics, are matters of wonder to many of the present age; but the means which they adopted to furnish, irrespective of cost, copious supplies of wholesome water for the purpose of dietetics, health and cleanliness, excite less of surprise than it does of admiration for their wisdom and sagacity in this respect.

Pure water in abundance was regarded by them not only as one of the greatest benefits, but as indispensable to life. In the magnitude of its supply, Rome seems to have surpassed all other ancient cities. During the reign of Nerva, after the Christian era, the aggregate flow of water into the city of Rome is estimated to have been not less than three hundred and fifty millions of gallons. Estimating the city to have contained at that day one million inhabitants, the supply equalled three hundred and fifty gallons per day, per individual. The aqueducts through which the waters were conveyed from various sources, were of the most magnificent and costly construction, and such was their durability that a portion of them, spared by conquering invaders, have survived the destroying hand of time.

The Aqua Claudia, begun by Nero and finished by Claudius, conveyed to the city sixty-four millions of gallons each day. This aqueduct formed a stream of thirty miles in length, and was supported on arcades through the extent of seven miles, and such was the solidity of its construction that it continues to supply the city at this time.

The waters of the river Anio were also conducted to Rome by two different channels; the first was carried through an extent of forty-three miles, and the latter upward of sixty-eight miles, of which six and a half miles formed a continued series of arches, many of them upward of one hundred feet in height. Compared with these, and many similar works of the ancients, the Croton, Cochituate, Fairmount, and Gunpowder Waterworks sink into insignificance. The wisdom of the ancient Romans, in the matter of a supply of pure water, is beginning to be appreciated by communities of the present day. That which but a few years since was considered to be a bountiful supply is no longer regarded as such.

In most English towns the water supply is calculated at about thirty or forty gallons for each person daily. In the United States, wherever public waterworks exist, the consumption is much greater, the average American citi

Read before the State Sanitary Convention at Norristown.

zen using, or wasting, more than twice as much as his London cousin. Marseilles, the only city of France with a proper water supply, will, when its projected works are completed, be able to furnish an average of 250 gallons per day, per person. Paris, with a population of 2,500,000, had, until recently, only 510,000 cubic metres of water, or about 150 gallons per day, per person, inclusive of water used for all purposes; but works were to have been completed in 1889 which would increase the supply 140,000 cubic metres per day, giving a total supply of 650,000 cubic metres, or nearly 200 gallons per day, per

person.

In New York City, with an estimated population of 1,500,000, the daily consumption of water is about 125,000,000, or an average of 83 gallons per person, per day; Philadelphia, estimated population 1,000,000, daily consump tion 88,000,000, average 88 gallons; Boston, estimated population 400,000, daily consumption 36,000,000, average 90 gallons; Baltimore, estimated population 500,000, daily consumption 40,000,000, average 80 gallons. The latter city has a maximum daily supply equal to about 500 gallons per person per day, which is probably the largest supply of any city in the world, except the city of Rome, which with a present population of 300,000, has a maximum water supply of 800 gallons per person, per day.

POLLUTION OF WATER COURSES.

Aggregations of population are generally found near some river, or other body of water which serves a double purpose:

1. To supply the population grouped upon it with water for domestic and public purposes.

2. To carry away the town filth, especially sewage matters.

It is with the pollution of water supplies as with diseases-" an ounce of prevention is better than a pound of cure." Many of the customs of mankind, however strongly they be recommended on the score of convenience, are open to objection with regard to their influence upon health; and the common sense of the age has at last arrived at the conclusion that the practice of recklessly polluting water courses must be abandoned, on account of injury which may possibly ensue to the public.

Every hygienic congress that has assembled during the last decade has decided by formal resolution and solemn vote that rivers ought not to be polluted, and that all refuse likely to pollute them must be gotten rid of in some other way than by casting it into water courses; but thus far no practical plan has been set forth by which that which is so plainly desirable can be rendered possible, unless we accept the sanitary paradox, that "all refuse likely to contaminate water courses should be passed through the soil by irrigation.'*

* Sewage farms can only be successful when the porosity of the soil is adapted for filtration, and when the area is sufficiently large for the work it has to do; but all sewage before being run upon the land should be treated so that secondary putrefaction cannot be set up, or the organic matter broken up into soluble and, therefore, more hurtful products. This especially is the case where the sewage is undergoing incipient putrefaction. Hence, while the effluent from an irrigation farm may be an excellent effluent, it is obviously unfit for drinking purposes, and should not be sent into a river from which the water supply of any town is drawn.

The relative wholesomeness of water is undoubtedly dependent upon the relative amount of certain kinds of organic substances which may be present, and the usual sources of depreciation may be stated as follows:

1. POLLUTION FROM MANUFACTORIES.

Many manufacturing industries yield large quantities of refuse liquid which is injurious by reason of matters either dissolved or held in suspension; but it would plainly be impossible either to require every manufacturer to be an agriculturist, and to hold land upon which his waste liquids might be poured out, or to require every farmer to place upon his land whatever the neighboring manufacturers might choose to send him. As a matter of fact, the suspended matters of most manufacturing industries soon fall to the bottom of the stream, and the dissolved matters are soon oxidized, and, therefore, the English law, so far as manufacturing wastes are concerned, is limited to flagrant cases, or to preventing the discharge of refuse into rivers in situations where a definite mischief would be wrought before any natural process of precipitation could be completed.

No doubt the tendency of the times is to carry restrictions further than they have been carried heretofore, partly because the dwellers by the banks of rivers are becoming more and more conscious of the charms of a pure and limpid stream, partly because experience has shown that the manufacturer, when prevented from discharging his waste in the accustomed way, has more than once found means of turning it to highly profitable account, and has in the long run been the chief gainer by a prohibition which at first he regarded as a hardship.

2. POLLUTION INCIDENT TO CULTIVATION OF THE SOIL.

The influence of the cultivation of farm lands in polluting streams running through them has been the subject of some investigation, and experiments bearing on the question have been made in England, France, Germany, Belgium, Austria and other European countries. The interesting point with reference to the pollution of water courses from this source, is the small amount of rainfall which actually passes through the soil, especially during the Summer months, at which season it has been found that there is almost an entire absence of pollution from this source. If lands have been heavily manured in the Winter or Spring, and the process is followed by wet weather, the percolation and consequent escape of noxious matters into an adjoining stream would, of course, be very much greater than if the Spring season were dry. Fortunately, however, at such season there are usually freshets, which rapidly and effectually cleanse the stream and counteract ill-effects.

The depreciation of water supplies by soil pollution is generally at its minimum in the Winter, when the ground is closed by frost, so that the Winter showers and water from melting snows do not soak into the ground, but flow over the surface into the creeks and rivers.

Dr. Gilbert says: "When manurial matters have passed through a considerable depth of soil, there is not so much danger from ordinary agriculture as is sometimes supposed, but it should be fully understood that water largely contaminated with any kind of putrefying organic matter is always unsafe as a source of domestic supply." This view is also maintained by the Rivers Pollution Commission of England. They have declared that "water collected from the drains of cultivated land is invariably more or less polluted with the organic matter of manure," and that, "such polluted surface or drainage water is not of good quality for domestic purposes," but they say "it may be used with less risk to health than polluted shallow well water, if human excrementitious matters do not form part of the manure applied to the land."

Dr. Brouardel, the distinguished Paris hygienist, in a report recently made to the Academy of Sciences of that city, has demonstrated the fact that the bacilli of typhoid fever will live during many months in the earth, and are finally carried by rains into water supplies a considerable distance from the place where they were deposited. Pasteur has shown this to be the case with the microbes of charbon and septicemia, and his experience has lately been confirmed by Bollinger, of Germany. Dr. Charrin, the eminent French biologist, has conclusively shown that the microbe of infectious pus will preserve its vitality for a long period in a cultivated soil. As we know that the fecal discharges of persons suffering from certain diseases are infected, it is easy to comprehend how the percolations of such materials into sources of drinking water may be fraught with disastrous consequences. It is indispensable to the health of communities, therefore, that the utmost care be taken to preserve the purity of their respective water supplies, and to guard them with unceasing care against every source of contamination.

tance.

3. POLLUTION FROM GRAVEYARDS.

Nitrogenous organic matter and ammonia are the dominant principles of water that has leached animal matter in a state of putrefaction, and these elements, which the water sometimes takes up in large quantities, especially from human bodies that are undergoing decomposition in the ground, are not completely separated by filtration through the soil. Rain water. falling upon a porous soil sinks vertically, unless it comes in contact with an impervious stratum, such as clay or stratified rock, when it may flow off horizontally to a great disIf water comes in contact with vegetable matter in the soil, it will take up a certain amount of carbonaceous matter, which may not be especially injurious unless in large amounts; but the case is quite different if the water should come in contact with decomposing animal matters, because the animal tissues, in undergoing putrefactive decomposition, give rise to very complex products, which are very soluble and extremely injurious to the quality of potable water. Unless the water filters through a quantity of soil, and soil of such a quality as will completely remove the products of decomposition, it is unsafe for domestic purposes, however far it may have passed under the ground before reaching the water supply.