brother visited his sisters in the country. Three weeks subsequent to his arrival one of these sisters sickened with scarlet fever, and a week later the other also. It seemed that the exposure must have occurred several days after his arrival in the country from some book or other infected article in his possession.

Such histories and experiences are not infrequent. They are common during epidemics of scarlet fever. They indicate an extraordinary attachment of the scarlatinous poison to objects, and show it is not gaseous nor readily volatilized. The fact of its portability and attaching itself to objects-carried long distances-that the poison is a fixity; that it is a germ, and that almost to a certainty the poisonous principle is confined generally, if not always, to the fine branny scales, and that the danger lies entirely in the period of desquamation, makes it criminal for physicians and nurses to neglect in the least strict quarantine and rigid antisepsis, for, in these precautions, intelligently and systematically enforced, lies the only hope of eradicating this highly infectious and dangerous disease. In the present state of our knowledge, the most reliable and certain. prophylaxis is the isolation of patient and nurses and the thorough and judicious employment of disinfectants upon their persons and in the apartments. All furniture and articles not absolutely required should be removed from the sick room, and no one should be allowed to enter it except the medical attendant and the nurses. Constant ventilation should be insisted upon by raising the lower sash of the window a few inches in mild weather. Even in stormy weather sufficient ventilation can be insured in this way without exposing the patient to currents of air, which should be avoided. The temperature of the room should be kept at about 70 degrees. Articles used about the patient, such as sheets, pillow cases, blankets or clothes, must be removed from the sick room until they have been disinfected by placing them in a tub of boiling water, in which carbolic acid and sulphate of zinc have been added, or in corrosive sublimate solution 1 to 1,000. They should be soaked in this for at least an hour and then again placed in boiling water for washing. Vessels used by the patient should have some of the disinfecting fluid constantly in them, and, immediately after being used by the patient, emptied and cleaned with boiling water. Water closets where the discharges are emptied should be disinfected from day to day during the illness by lime or sulphate of zinc. Ail straw and feather beds should be burned, and the last should never be replaced. An old feather bed, handed down from generation to

generation, is an abomination in the sight of all sanitary nations and peoples. Old sterilized cloths should be used about the patient instead of handkerchiefs, and when once used should be burned: The patient should be kept well anointed with carbolized vaseline or lysol and vaseline, as it not only serves to allay the intolerable itching, but serves the double purpose of rendering the fine branny scales heavy, thus preventing them from flying about the room, and also probably destroys to a large extent the infectious principle of this disease. The physician, before entering the sick room, should anoint his face and hands with the above ointment; should put on a closely fitting gown and hood. After coming out he should remove them, place them in a close-fitting bag, in which is a piece of cotton saturated with formaldehyde. He should wash and disinfect his hands and face before leaving for his office or home, or to visit other patients. The nurses should use the same precautions, and before leaving the house should take a bath, with a complete change of clothing. After convalescence is fully established, and after there has been complete desquamation, the rooms, clothing, furniture and everything else that has been in the least exposed to the scarlatinous poison should be thoroughly disinfected. Probably the best, cheapest and safest germ destroyer is a new disinfectant, formaldehyde. Because of its cheapness and simplicity in using, boards of health are generally recommending it. Perhaps all we are told in its praise is not entirely warranted, but enough is proven to establish its high value in this direction.

THE WRONG POCKET.-Two ladies entered a car at an hour of the day when seats are a possibilty. One was a stout, over-dressed lady, the other was evidently her daughter. "Shall I pay the fare, mamma? I have my purse with me," said the young lady sweetly. "Oh, no; I'll pay. I have plenty of change." Thereupon she leaned sideways and commenced the intricate process of searching her draperies for her pocket. After a minute or two of fumbling, during which her face grew an apoplectic red, she exclaimed, tragically, "Laura! what shall I do? I've been robbed! My purse is gone-my pocket is entirely empty." "Perhaps, madam," said the gentleman by her side, into whose coat-pocket she had thrust her hand, "perhaps if you search your own pocket instead of mine you will be more likely to find your purse."

THE CAUSES AND PREVENTION OF WATER FER

MENTATION.*

BY SAMUEL MCELROY.

Rapid progress in biological science, coming, as it does, to the aid of chemical science, and, in such cases as water analysis, furnishing what hydraulic engineers have long felt to be a needed supplement, within twenty years has changed the theories and practice of our medical authorities, and is rapidly leading, in agriculture and otherwise, to radical changes important to public welfare.

The fermentation of water is a subject which grows in importance with the rapidly-growing demand for, and distribution of, water in the various centres of population. The careful student who has collated the experience of the more populated centres on this point finds that fermentation is an active and universal law of depuration in reservoirs and other bodies of water, and demands a systematic attention which it has not, as yet, received in water-supply design.

Contamination, year after year, both in summer and winter, of the most prominent supplies has shown, at times, to any careful observer, the effects of the process by which nature depurates contaminated water. These effects have differed in period and intensity, but their occurrence has been common.

Actuated by local pride, when troubles come which should have been anticipated and prevented, city authorities have, in various times and ways, glossed over, tried to explain away, or ignored these evidences of contamination; and quite a number of those who ought to know better-chemists, biologists, engineers, commissioners have insisted that the trouble was only temporary, its causes more or less mysterious, its effects more or less mythical, and its sanitary effects harmless. The good name of the supply is to be guarded, and the suffering consumers are cautioned against any public clamor.

The general panacea of these wise men is flushing the mains at the street hydrants, an operation performed at night, to save critical eyes from a shock. This shows what deposits the mains. collect under their usual slow motion, and discharge under rapid

*From Engineering Magazine for July, 1897.

currents; and it usually aggravates the trouble, since the oxides of constant pipe-disintegration are, in themselves, valuable correctives, and, if the reservoir is contaminated by what it accumulates in its depths, the renewed supply more surely shows it, under the erroneous practice which neglects surface flow into the mains.

To the hydraulic engineer who has made this process a study, and is familiar with the theories and remedies of ancient practice, the causes and effects are plain, and the remedies equally so. Unfortunately, however, in the engineering profession struggling through a transition stage, studied experience has no adequate market value, and centres of population gain lessons by a prolonged suffering which is strangely universal.

Two great natural laws come into action here. From its abrasive weight, its absorbing power, its active solutions, and its incessant motion, water as rain, as flowing veins and currents, as expanding ice, or when distilled by evaporation, becomes rapidly contaminated in its descent through the atmosphere and its flow over, or through, the earth. It rapidly takes up, or becomes impregnated with, vegetable and animal matter, diseased or dead, and mineral salts.

Then, in the wonderful provision made for man's comfort and health, come into action the sanitary forces whose office is to depurate this organic pollution. Sunlight, as heat and otherwise, has one function; oxygen in aeration and motion has another; and the teeming sanitary police of the lower organic world, the algoid and fungoid ministry, with that of the protozoic forms, come in to fulfil their important share of the work. These forces-heat, air, and microbes-are the remedial trinity of diseased water.

The cause, then, plainly, is contamination by diseased or dead. organic matter; and, since fermentation is, generally, nature's corrective remedy, the process here is putrefactive fermentation; and the odors and flavors observed are the usual evidences of this process, which must continue until depuration is accomplished. No scientific student considers heat, or oxidation, or microbes a direct cause of this phenomenon. He knows perfectly well that each is simply remedial for a distinct organic cause.

Let us now apply these premises to the supply-condition of the fourth city of the United States. Brooklyn, in 1895, is reported to have used 80,124,432 gallons of water per day, or more than 100 gallons per capita, for the twenty-five wards supplied by the city works.

The city works department, from amounts raised by tax and assessments, expended in 1895, $5,827,482, of which $761,717 was for water maintenance, including the respectable sum of $393,275 for salaries alone.

In addition, the house-holders paid $1,863,678 as water rates-a total of $2,625.495 for the luxury of water-supply.

Brooklyn inaugurated in 1856 a supply of the highest rank in quantity, quality, and availability. The engineering theory of this plan may be thus stated:

Long Island, in the main, is composed of a porous mass of sand and gravel, sloping up from the ocean on one side and the sound on the other to a central ridge, which rises several hundred feet above tide, and contains occasional deposits of clay, bowlders, etc. The rain falling on this surface is readily absorbed, and passes down to a saturated bed, as through an enormous filter, which rises landward from tide-level, with an hydraulic frictional slope, generally of eight or ten feet per mile, except near tide. On the Hempstead plains, at a distance of 9.38 miles from tide, and a ground elevation of about 210 feet, the water stands 78 feet above-a mean slope of 8.34 feet per mile, and a direct filtration, to reach it, of 132 feet.

Along this southern slope, easterly from New York Bay, depressions occur at frequent intervals in this formation, near tide, generally as swamp beds from which powerful springs issue, forming creeks, each flowing to tide through its own valley; and there is considerable appropriation of these as mill-ponds, near tide.

Under the plan of 1856, an intercepting aqueduct was built, from the Ridgewood pump well to Hempstead reservoir, 12.39 miles, completely controlling a basin of 88.64 square miles. Of about eighteen creeks which it crossed, five of the more prominent were selected, the mill-ponds being formed into supply reservoirs, and a sixth was excavated on Clear Stream. Abundant experience has shown their flow-about 36,000,000 gallons per day; the rest, on a catchment of not less than 1,200,000 gallons per square mile, or 106,000,000 per day, wasting at tide unless intercepted.

In 1875, under the Kingsley regime, Brooklyn expended about $1,500,000 for the Hempstead storage reservoir, endorsed as capable of furnishing 100 days' summer supply of 10,000,000, in addition to the creek flow of about 8,000,000. It has a maximum capacity of 850,000,000, at a depth of 29 feet, which it has never been able to realize, and its capacity at any level suppresses the natural stream flow in proportion.