The object of hygiene is the preservation of health. Hitherto, we have considered, at some length, the science of functions, or Physiology, and now, under the head of Hygiene, we will give an outline of the means of maintaining the functional integrity of the system. It is difficult to avoid including under this head Preventive Medicine, the special province of which is to abate, remove, or destroy the many causes of disease. The Greeks bestowed divine honors upon Aesculapius, because he remedied the evils of mankind and healed the sick. The word hygiene is derived from Hygeia, the name of the Greek goddess of health. As male and female are made one in wedlock, so Medicine and Hygiene, restoration and preservation, are inseparably united. Hygiene inculcates sanitary discipline, medicine, remedial discipline; hygiene prescribes healthful agencies, medical theory and practice, medicinal agencies; hygiene ministers with salubrious and salutary agents, medicine assuages with rectifying properties and qualities; hygiene upholds and sustains, medical practice corrects and heals; the one is preservative and conservative, the other curative and restorative. These discriminations are as radical as health and sickness, as distinct as physiology and pathology, and to confound them is as unnatural as to look for the beauties of health in the chamber of sickness. In the following pages we shall introduce to the reader's attention several important hygienic subjects, although there are many more that ought to receive special notice. Such as we do mention, demand universal attention, because a disregard of the conditions which we shall enumerate, is fraught with great danger. Our lives are lengthened or shortened by the observance or neglect of the rules of common sense, and these do not require any great personal sacrifice, or the practice of absurd precautions. PURE AIR FOR RESPIRATION.Ordinary atmospheric air contains nearly 2,100 parts of oxygen and 7,900 of nitrogen, and about three parts of carbonic acid, in 10,000 parts; expired air contains about 470 parts of carbonic acid, and only between 1500 and 1600 parts of oxygen, while the quantity of nitrogen undergoes little or no alteration. Thus air which has been breathed has lost about five per cent. of oxygen and has gained nearly five per cent. of carbonic acid. In addition the expired air contains Therefore, every human being should be supplied, by proper ventilation, with a sufficient supply of fresh air. Every adult individual ought to have at least 800 cubic feet of air-space to himself, and this space ought to communicate freely with the external atmosphere by means of direct or indirect channels. Hence, a sleeping-room for one adult person should not be less than nine by ten feet in breadth and length and nine feet in height. What occurred in the Black Hole at Calcutta is an excellent illustration of the effect of vitiated air. One hundred and forty-six Englishmen were confined in a room eighteen Ventilation of School Rooms. The depression and faintness from which many students suffer, after being confined in a poorly ventilated school room, is clearly traceable to vitiated air, while the evil is often ascribed to excessive mental exertion. The effect of ventilation upon the health of students is a subject of universal interest to parents and educators, and at present is receiving the marked attention of school authorities. Dr. F. Windsor, of Winchester, Mass., made a few pertinent remarks upon this subject in the annual report of the State Board of Health, of Massachusetts, 1874. One of the institutions, which was spoken of in the report of 1873, as a model, in the warming and ventilation of which much care had been bestowed, was visited in December, 1873. He reports as follows: "I visited several of the rooms, and found the air in all, offensive to the smell, the odor being such as one would imagine old boots, dirty clothes, and perspiration would make if boiled down together; again, in the new model school-house the hot air enters at two registers in the floor on one side, and makes (or is supposed to make) its exit by a ventilator at the floor, on the other side of the room." The master said "the air was supposed to have some degree of intelligence, and to know that the ventilator was its proper exit." Thorough ventilation has been neglected by many school officials on account of the increased expense it causes. In our climate, during seven months at least, pure atmospheric air must be paid for. The construction of vertical ducts, the extra amount of fuel, and the attendant expenditures are the objections which, in the opinion of many persons, outweigh the health and happiness of the future generation. It is necessary for the proper ventilation of our school rooms that an adequate supply of fresh air should be admitted, which should be warmed before being admitted to the room, and which should be discharged as contaminated, after its expiration. The proper ventilation of the school room consists in the warming and introduction of fresh air from without, and the discharge of the expired and unwholesome air from within. This may be accomplished by Ventilation of Factories and Workshops. This is a subject which demands the immediate attention of manufacturers and employers. The odors of oil, coal gas, and animal products, render the air foul and stagnant, and often give rise to violent diseases among the operatives. From two to four hundred persons are often confined in workshops six hundred feet long, with no means of ventilation except windows on one side only. The air is breathed and re-breathed, until the operatives complain of languor and headache, which they attribute to overwork. The real cause of the headache is the inhalation of foul air at every expansion of the lungs. If the proprietors would provide efficient means for ventilating their workshops, the cost of construction would be repaid with compound interest, in the better health of their operatives and the consequent increase of labor. Our manufacturers must learn and practice the great principle of political economy, namely, that the interests of the laborer and employer are mutual. Ventilation of our dwellings. Not less important is the ventilation of our dwellings; each apartment should be provided with some channel for the escape of the noxious vapors constantly accumulating. Most of the tenements occupied by the poor of our cities are literally dens of poison. Their children inhale disease with their earliest breath. What wonder that our streets are filled with squalid, wan-visaged children! Charity, indeed, visits these miserable homes, bringing garments and food to their half-famished inmates; but she has been slow to learn that fresh air is just as essential to life as food or clothing. Care should be taken by the public SITE FOR HOMES.Malaria. When about to construct our residences, besides securing proper ventilation and adequate drainage, we ought to select the location for a home on dry soil. Low levels, damp surroundings, and marshy localities not only breed malaria and fevers, but are a prolific cause of colds, coughs, and consumption. Care should be taken not to locate a dwelling where the natural currents of air, or high winds, will be likely to bring the poison of decayed vegetable matter from low lands. Certain brooks, boggy land, ponds, foggy localities, too much shade, all these are favorable to the development of disease. Then the walls of a building should be so constructed as to admit air between the exterior and interior surfaces, otherwise the interior of the house will be damp and unwholesome. In the dead of winter in northern latitudes Neither should the dwelling be shaded by dense foliage. The dampness of the leaves tends to attract malaria. Trees growing a little distance from the house, however, obstruct the transmission of unhealthy vapors arising beyond them. Malaria generally lurks near the surface of the earth, and seems to be more abundant in the night time. Persons sleeping in the upper story of a house may escape its morbid influence, while those occupying apartments on the lower floor, become affected. DAMP CELLARS.Damp cellars, under residences, are a fruitful cause of disease. Dr. Sanford B. Hunt, in an article in the Newark Daily Advertiser, speaking of the recent epidemic of diphtheria in New York City, says: "Pestilences that come bodily, like cholera, are faced and beaten by sanitary measures. Those which come more subtly need for their defeat only a higher detective ability and a closer study of causes, many of which are known, but hidden under the cellars of our houses, and which at last are only preventable by public authority and at public expense in letting out the imprisoned dampness which saturates the earth on which our dwellings are built. Where wood rots, men decay. This is clearly shown in the sanitary map printed in the Times. In the great district surrounding Central Park, and which participates in its drainage system, there are no cases. On the whole line of Fifth Avenue there are none. The exempt districts are clearly defined by the character of the soil, drainage, and sewerage, and by the topography, which either has natural or artificial drainage, but most of which is so dry that only surface-water and house-filth—which does not exist in those palaces—can affect the health of the residents. But in the tenement houses and on the made lands where running streams have been filled in and natural springs choked up by earth DUST AND DISEASE.The air we breathe is heavily loaded with minute particles of floating dust, their presence being revealed only by intense local illumination. Professor Tyndall says: "solar light, in passing through a dark room, reveals its track by illuminating the dust floating in the air. 'The sun,' says Daniel Culverwell, 'discovers atoms, though they be invisible by candle-light, and makes them dance naked in his beams.'" After giving the details and results of a series of experiments in which he attempted to extract the dust from the air of the Royal Institute by passing it through a tube containing fragments of glass wetted with concentrated sulphuric acid, and thence through a second tube containing fragments of marble wetted with a strong solution of caustic potash, which experiments were attended with perfect failure, the Professor continues, "I tried to intercept this floating matter in various ways; and on the day just mentioned, prior to sending the COTTON-WOOL RESPIRATOR."I now empty my lungs as perfectly as possible, and placing a handful of cotton-wool against my mouth and nostrils, inhale through it. There is no difficulty in thus filling the lungs The application of these experiments is obvious. If a physician wishes to hold back from the lungs of his patient, or from his own, the germs or virus by which contagious disease is propagated, he will employ a cotton-wool respirator. If perfectly filtered, attendants may breathe the air unharmed. In all probability the protection of the lungs and mouth will be the protection of the entire system. For it is exceedingly probable that the germs which lodge in the air-passages, or find their way with the saliva into the stomach with its absorbent system, are those which sow in the body epidemic disease. If this be so, then disease can be warded off by carefully prepared filters of cotton-wool. I should be most willing to test their efficacy in my own person. But apart from all doubtful applications, it is perfectly certain that various noxious trades in England may be rendered harmless by the use of such filters. I have had conclusive evidence of this from people engaged in such trades. A form of respirator devised by Mr. Garrick, a hotel proprietor in Glasgow, in which inhalation and exhalation occur through two different valves, the one permitting the air to enter through the cotton-wool, and the other permitting the exit of the air direct into the atmosphere, is well adapted for this purpose. But other forms might readily be devised." LIGHT AND HEALTH.Our dwellings ought freely to admit the sunlight. Diseases which have baffled the skill of physicians have been known to yield when the patients were removed from dark rooms to light and cheerful apartments. Lavoisier placed light, as an |