equilibrium of heat of the body and causing nervous disturbances detected by the sensation of pain as rheumatism, crick in the neck, etc. A room, to be properly ventilated, should have an entrance to air near the floor so as to move the heavy air, and an exit near the ceiling so as to give vent to the more rarefied. This mode will secure a proper motion and mixing of the air and a constant exchange from an impure to a purer atmosphere. A wide, open chimney may serve for the admission of cool air, while a ventilator above would give exit to the warmer air; but by far more preferable would be two ventilators independent of this; one applied near the floor, another near the ceiling. A very good arrangement of this kind may be applied to a window. Bore a hole of four inches in diameter in a lower pane and another of the same size in the upper pane. To prevent strong drafts of air from these apertures, place a shield in front of the holes riveted through the glass, but so made that when in position you can place your hand in the upper part of the shield between it and the pane of glass on the top of the window; in the lower pane reverse the shield, so that the current of air from the hole below will be directed downwards, and from the hole above upwards. These currents may be modified by a properly adjusted valve to the openings. This will secure a proper circulation of air without disfiguring the appearance of the window.

An impromptu apparatus may also be applied to the windows. A strip of wood four inches wide may be placed between the window and the sill with two holes retaining a tube, bent downward for the lower, and bent upward for higher.

Of course this ventilation may be secured by any other mode, but the principle to be observed is that there should be two ventilators, one to admit fresh air near the floor, another to give exit to impure air near the ceiling.

The detection of impurity of the air of a room by smell has been tested by Dr. de Chaumont, and in a communication to the Royal Society he gives the following proportions to carbonic acid according to the sense of smell, as follows:

In these experiments Dr. de Chaumont takes .0002 of carbonic acid per cubic foot as the standard of impurity, in addition to .0004 carbonic acid per cubic foot as the normal amount of carbonic acid in the outer air, so that when the amount of carbonic acid in an inhabited room reaches .0006 the air becomes impure.

In admitting air to rooms care should always be taken that it does not come from the proximity of receptacles of dirt, or of stagnant water or the immediate surface of the ground; for such air is generally impregnated with various substances held in suspension.

Gentlemen, I feel conscious of the superficiality of this paper. But the subject is of larger proportions than a paper for this occasion would admit. Many important points on the hygiene of dwellings have not been touched upon, and even those I have treated lack many of the scientific problems which I might present. The question of warming, an analysis of the various mechanical appliances for the purpose and use of fuels, and their effect upon ventilation and the production of various gases, form such a wide subject that I could not undertake it without passing away beyond the limits of your indulgence.

The purity of water which every householder should secure for his family, I could not discuss without going into a very lengthy examination of a subject which would fill a volume by itself.

I hope the Bureau of General Sanitary Science, Hygiene and Climatology will take up these subjects one by one in the future, in preference to general subjects which cover too much ground. Soils, drainage, ventilation, warming houses, building materials, water closets, sewers, adulteration of food, cooking, pure water, pure air, etc., are subjects each of which is so extensive as to occupy all the time that may be allotted to these papers. I have given you only a few of the salient points to secure a healthy home, and

now apologize for the imperfection of my limited, but well intended efforts.

Before closing, I must say that legislation should be demanded on building regulations; these should be of the most stringent character; for what will avail your efforts in securing a healthy home if your neighbor, criminally indifferent, poisons your neighborhood? The burden of legislation is the protection of the rights of person and property and the pursuit of industry, compatibly with public health; for health is the royal arch upon which is built social organizations. Let yellow fever or cholera enter a community and anarchy and disorganization follow. What deteriorates public health deteriorates industry and nations. Political economy demands health and strength. Kingdoms and empires have fallen from physical degeneracy, and morality decreases "pari passu" with physical weakness. The money stinted on the preservation of health will be spent in supporting hospitals and infirmaries. The thousands who, from physical inability remain idle and are a charge to a community, if in health would work in the shops and in the fields, adding thus wealth and strength to the nation. Compute what the late epidemics have cost New Orleans, Grenada, Vicksburg or Memphis, and the nation at large. If gold were that on which only the hopes of man should feed, then for the sake of gold every man should be a sanitarian.

Philanthropy comes like an angel of mercy at the time of desolating epidemics, but philanthropy is too late then; it can only assuage, it can neither prevent nor cure.

PERSONAL HYGIENE AS TO DISTRICT INHABITED.

BY E. U. JONES, M.D.

The causes of disease have been sought everywhere. The air has been held responsible for a larger share than it could truly claim. The waters have been accused of those faults which could not be directly attributed to the air. Floating spores have been called upon to fill some otherwise unexplained gaps. Microzymes have been adjudged guilty of almost everything, and their inocuousness having been proved, the invisible infinitesimal world has now the blame laid on its shoulders. There cannot be all truth in any one of these statements. Because the air, the water, the spore, the microzyme, have had strong circumstantial evidence brought that they have sometimes, and in certain instances, been the producers, the initiators, the carriers of disease, it is not right that they should each and individually be adjudged guilty of all.

The air is itself purity. Being the one-fifth attenuation of oxygen in nitrogen, it contains within itself only the elements of life and health, and has no immediate connection with disease or death. Water is in itself purity, and can longer sustain the integrity of human life than food without it; it is an actual necessity of our living, and has in itself no element of disease. The spore is a thing of life, and the most extended evidence does not hold it guilty of the terrible crimes charged against it. The microcosmos is peopled with life, and the worst that can possibly be laid at its door is that this life may be the offspring, but not the origin of disease and ultimate death.

But yet the air, and the water, and the spore, and the microzyme do have connection with disease and death. What is the mediate which links the two? The answer is: the conditions, both in the object and the subject. And the chief of these conditions is the soil-conditions under which we live. These conditions vary

for the different portions of the habitable earth, and have relation not merely to the portion of the earth with which we are in daily contact, but with that underlying portion which is hidden from our sight, and, to a great extent, from our immediate possible knowledge. These two portions are divided technically into soil and sub-soil, and have mutual, and, to a degree, interchangeable relations. Nor, in this consideration, must we be confined to that friable and disintegrated portion which we cultivate, and which we are accustomed agriculturally to treat as soil and sub-soil; sanitary relations lie deeper, and take account of the solid rock foundations, often lying but a few feet below that surface over which we tread and live. The softer parts of this same rock we cultivate, and, when intermingled with animal and vegetable organic matters in varying quantities and under varying conditions, with air and water, we call it earth. The organic matters, the air and water, may be called adventitious components, the basis of all true soils being mineral. But it is evident that the mass of adventitious components varies greatly in the different soils as they now exist, from the minimum quantity in the clay and sands to the maximum quantity in the rich loams and marls, so that the factor of the upper soils is by no means an unimportant one in the hygiene of the district inhabited. But this factor does not solely determine its own hygienic relation, for that is controlled, in a greater or less degree, by the underlying sub-soil. The question here becomes, not so much what that may contribute to the making of the upper soil, or what it may send upward through this overlying stratum, but what is its porosity both to air and water, and by its thus determining what it will and can take away from that overlying soil. The question of the porosity of the sub-soil, therefore, becomes an all important one in considering the sanitary relations of any district. Air and water are the two great solvents of nature; the one by its power of making and causing chemical changes, and the other by its transferring in solution the results of these changes. It is almost exclusively through the agency of these two that whatever is deleterious in the soil is carried into the human system, and is able there to find a lodgment.

When ordinary atmospheric air has entered the soil as one of its