his taking to bed. When he first goes into the open air he should be warmly clothed from head to foot. The care of patients who have recovered from measles differs but little from that of scarlet fever. Exposures to draughts of cold may bring on pneumonia. As long as there is cough the patient should keep his room. Not unfrequently this disease leaves behind it a chronic pneumonia, bronchial catarrh, or other weakness of the lungs.

[NOTE BY THE SECRETARY.]

When that great physician of New England, DR. JAMES JACKSON, had reached the pinnacle of his fame and was calmly awaiting the call of the Master to come up higher! his great warm heart had lost none of its love for humanity by reason of extreme age, and he crowned his distinguished life by the gift of a little volume of Letters to a Young Physician, in which he discoursed on such familiar ailments as are thought unworthy of much notice in systematic text-books, giving particular instructions for their treatment. Likewise, the great surgeon of America, PROF. S. D. GROSS, after spending more than a half century in active work, by his patient studies and voluminous writings, instructing the profession in a thousand different ways, and receiving greater honors than were ever before bestowed upon an American surgeon, has not thought it unworthy of his great name to become the patron of a movement for better nursing of the sick; and accordingly he sent to the Philadelphia Medical News, last September, a communication on "The Importance of having Trained Nurses for the smaller towns and the rural districts, and the proper method of securing them."

He says in that paper: "Having long entertained the conviction that good nursing was an indispensable aid to the successful treatment of diseases and injuries, and conscious how little interest the profession and the public felt on the subject, I considered it my duty during a visit I made to Europe, in 1868, to make myself fully acquainted with its various and multifarious requirements. For this purpose, I examined many of the prominent hospitals and training schools for nurses, and, after my return, embodied the results of my observations and reflections in a report which, the following year, as chairman of a committee appointed at my instance the previous year, was submitted to the American Medical Association at its meeting at New Orleans. In order to impart thorough scope and efficiency to this scheme, I suggested that district schools should be formed and placed under the guardianship of the county medical society, the members of which should make it their business to deliver, at such time and place as might be most convenient, instruction in the art and science of nursing, including the elements of hygiene, and every other species of information necessary to qualify the student for the important, onerous, and responsible duties of the sick-room.

"The report bore good fruit; it served to arouse attention to the subject on the part both of the profession and the public, and soon led to the formation of training-schools for nurses in some of our larger cities, and, among others, to the admirable ones at New Haven and on Blackwell's Island, New York; but it failed of its object in the rurul districts, where trained nurses are just as much a necessity as anywhere else.

*

*

*

**

*

"In the first place, I desire to bear testimony to the fact that nursing is not only an extremely useful, but a highly honorable pursuit worthy of the ambition of any respectable person, whether man or woman. Trained nursing is rapidly assuming the form of a dignified profession. It is no longer a menial occupation, but an art and a science. A well-educated nurse must necessarily be a person of refinement and of more or less culture. Such a nurse commands high wages, or, to put it in a more proper way, high fees, is much sought after, and, like the medical attendant, is entitled to the respect and confidence of the family in which he or she renders the service. 'From the want of timely care,' says Armstrong, the poet-doctor, 'millions have died of medicable wounds;' and millions, I am sure, die every year from a want of proper nursing. A good nurse is the right hand of the physcian. If his injunctions, in the way of medicine, food, drink and other necessaries, are not faithfully carried out during the intervals of his visits, how will it be possible for him to combat disease successfully? In many cases the recovery of the patient is due more to good nursing than to the skill of the physician. When I come to die, let me have plenty of light and pure air in my room, and at my bed side a kind and accomplished nurse, a member, if possible, of that noble sisterhood, the Sisters of Charity, who are doing everywhere such noble work in the interest of the sick and the dying."

THE RELATIONS OF THE SOIL TO HEALTH.

BY GEORGE H. ROHE, M. D., PROFESSOR OF HYGIENE AND CLINICAL DER-
MATOLOGY, COLLEGE OF PHYSICIANS AND SURGEONS, BALTI-

MORE, MEMBER OF THE AMERICAN PUBLIC HEALTH
ASSOCIATION, ETC.

I. THE SOIL.

That wisest and most learned of the ancients, Hippocrates, called the Father of Medicine, treated at length in one of his works, of the sanitary influence of the soil. Others of the older writers, especially Herodotus and Galen called attention to the same subject, and Vitruvius, the celebrated Roman architect, who flourished about the beginning of the Christain era, taught that a point of first importance in building a dwelling was to select a site upon a healthy soil.

From this time until the beginning of the eighteenth century, very little of value is found in medical literature bearing upon this subject. In 1717, however, Lancisi published his great work on the causes of malarial fevers in which he laid the foundation for the modern theory of malaria and pointed out the relations existing between marshes and low-lying lands and those diseases, by common consent, called malarial. Other authors of the eighteenth, and the early part of the nineteenth century, refer to the connection between the soil and disease, but exact investigations have only been made within the last thirty years. The general want of definite knowledge upon this subject, even among well-educated people is the occasion of the following pages.

When we consider that the air we breathe, and much of the water we drink, are influenced in their composition by the matters in the soil, the great importance of possessing a thorough knowledge of the physical and chemical conditions of the soil becomes evident to every one.

In the hygienic, as in the geological sense, we include rock, sand and gravel in the consideration of soils.

The soil, as it is presented to us at the surface of the earth, is the result of long ages of disintegration of the primitive rocks by the action of the elements, of the decomposition of organic remains, and possibly, of accretions of cosmical dust. The principal factor, however, is the action of water upon rock, in leveling the projections of the earth's surface, produced by volcanic action.

Soils vary considerably in physical and chemical constitution. We may have, for example, a soil consisting exclusively of sand, of clay, or of disintegrated calcareous matter. Other soils may consist of a mixture of two or more of these, together with vegetable matter undergoing slow oxidation. In forests, we find a layer of this slowly decomposing vegetable matter of varying thickness covering the earthy substratum. This organic layer is called humus, and when turned under by plough or spade, and

mixed with the sand or clay-base, it constitutes the ordinary agricultural

soil.

II.—THE ATMOSPHERE OF THE SOIL, OR GROUND AIR.

The interstices of the soil are occupied by air or water, or by both together. The soil's atmosphere is continuous with, and resembles in physical and chemical properties that which envelopes the earth. Its proportion to the mass of the soil depends upon the degree of porosity of the soil and upon the amount of moisture present. In a very porous soil, such as for example a coarse sand, gravelly loam or coarse-grained sandstone, the amount of air is much greater than in a clayey soil, granite or marble. So, likewise, when the soil contains a large proportion of water the air is to this extent excluded. The porosity of various soils, as evidenced by the amount of air contained in them is much greater than would, at first thought, be supposed. Thus it has been found that porous sandstone may contain as much as one-third of its bulk of air, while the proportion of air contained in sand, gravel or loose soil may amount to from thirty to fifty per cent.

The ground-air is simply the atmospheric air which had penetrated into the interstices of the soil and taken part in the various chemical decompositions going on there. In consequence of these chemical changes the relative proportions of the oxygen and carbonic acid in the air are changedoxygen disappearing and giving place to carbonic acid. It is well-known that during the decay of vegetable matter in the air, carbonic acid is formed; one constituent of this compound, the carbon being derived from the vegetable matter while the oxygen is taken from the air. Hence, if this action takes place where there is not a very free circulation of air, as in the soil, the air there present soon loses its normal proportion of oxygen, which enters into combination with the carbon of the vegetable matter to form carbonic acid.

Thirty years ago, MM. Boussingault and Levy, two distinguished French chemists, examined the air contained in ordinary agricultural soil, and found that the oxygen was diminished to about one-half of the proportion nominally present in atmospheric air, while the carbonic acid was enormously increased, The exact results obtained by Boussingault and Levy were as follows:

In one hundred volumes of ground air there were 10.35 volumes of oxygen, 79.91 volumes of nitrogen, 9.74 volumes of carbonic acid. In atmospheric air, on the other hand, there are in one hundred volumes 20.9 volumes of oxygen, 79.1 volumes of nitrogen, 0.04 volumes of carbonic acid, or about one twenty-fifth of one per cent. of carbonic acid.

In spite of the striking results obtained by these two chemists, very little attention was paid to them by sanitarians, as very few seemed to have any clear notion of the relations existing between the motions of the air above ground and that under ground.

In 1871, however, Prof. Von Pettenkofer, of Munich, whose authority in sanitary matters is second to none, published the results of his own examinations into the constitution and physical conditions of the ground air, and the relations of the latter to the propagation of epidemic diseases. These researches, which created a wide-spread interest in the subject were extended

by other observers in all parts of the world. These observers, prominent among whom were Professors Fleck and Fodor, in Germany; Drs. Lewis and Cunningham, in India; Prof. Wm. Ripley Nichols, in Boston, and Surgeons J. H. Kidder and S. H. Griffith of the U. S. Navy, in Washington, demonstrated that the increase of carbonic acid in the ground air is due to increased vegetable decomposition and to lessened permeability of the soil. A permeable, that is to say, a sandy or gravelly soil, is likely to contain less carbonic acid in its atmosphere than a dense, less permeable clay, although the amount of decomposition going on, and the production of carbonic acid in the former may considerably exceed the latter. In the loose sandy soil, the circulation of the air is less obstructed, and the carbonic acid may easily escape and be diffused in the superincumbent air, while the close-pored clay imprisons the carbonic acid and prevents or retards its escape into the air above.

The disappearance of oxygen from the ground atmosphere is coincident with the production of an equivalent amount of carbonic acid. It appears from this that in the soil an oxidation of carbonaceous substance takes place, the product of which is the excess of carbonic acid in the ground air. Prof. Nichols has found the proportion of carbonic acid in the air taken from a depth of ten feet below the surface in the "made land" of Boston, amount to 21.21 per thousand, the observation being made in August. In December, at a depth of six feet, the proportion was 3.23 per thousand. Fodor, in Buda-pesth, found the proportion of carbonic acid to be 107.5 per thousand (over 10 per cent.), the air being taken from a depth of thirteen feet.

Movements of the ground-atmosphere are principally due to differences of pressure and temperature in the air above ground. Owing to such differences the air from the soil frequently permeates houses, entering from cellars or basements. In winter, when the air of houses is very much more heated, (and consequently less dense) than the air out of doors, the difference of pressure, thus caused, draws the ground-air up through the house, while the cold external atmosphere penetrates the soil and occupies the place of the displaced ground-air.* A similar effect occurs in consequence of heavy rains. The water fills up the interstices of the soil near the surface and forces the ground-air out at points where the pores remain open. These places are the dry ground under buildings, where the air escapes and passes through floors and ceilings into the house above. Heavy rains may thus be the cause of pollution of the air in houses. The greater the porosity of the soil, the more likely is this to happen. This pollution of the house-air may be prevented by having impervious floors and walls to cellars and basements, or by interposing a layer of charcoal between the ground and the floor of the house.

In the spring and early summer the ground being colder than the air above it, and the ground-air consequently heavier and denser, the latter is not easily displaced. It is perhaps due to this fact that those infectious diseases which are probably dependent upon the movements of the groundair, are less prevalent in the spring and early summer than in the latter *It is, of course, not strictly correct to say that the air is drawn up through the house by the diminution of pressure; it being rather forced out of the soil by the colder and denser outside air; but the phrase is sufficiently exact and will be readily understood.

part of summer, autumn and early winter. In the autumn the ground-air being warmer than the air above ground is easily displaced by the latter and forced out into the streets and houses to be inspired by mén and animals. The same conditions may explain the greater likelihood of infection at night, which is proven for such diseases as malarial and yellow fevers. The colder outside air penetrates the interstices of the soil and forces out the impure ground-air.

The researches of Fodor have demonstrated that the proportion of carbonic acid in the ground-air may be taken as an approximative measure of the impurity of the soil whence the air is taken. The influence of the permeability of the soil, as before pointed out, must however not be overlooked in estimating the signification of the carbonic acid. Fodor has shown that the proportion of carbonic acid in the ground-air, and consequently the amount of organic decomposition, is greatest in July and least in March. That the carbonic acid is derived from the decomposition of organic matter, has been proven by Pettenkofer. This observer examined specimens of air brought from the Lybian desert, and found that the proportion of carbonic acid in the ground-air was exactly the same as in the air collected above ground. There being no vegetable growth in the desert there can,, of course, be no vegetable decomposition going on in the soil.

The excess of carbonic acid in the ground-air is an indication of the deficiency of oxygen as has been shown. The air at a depth of thirteen feet below the surface was found to contain only from 7 to ten per cent of oxygen-one-half to one-third of the normal proportion. Many basements occupied by people as living rooms extend from five to ten feet underground, and hence are liable to be supplied with an atmosphere approaching in impurity that just mentioned. It requires no very vivid imagination to appreciate the dangers to health that dwell in such habitations.

III. THE WATER OF THE SOIL, OR GROUND-WATER.

At a variable depth below the surface of the ground, a stratum of earth or rock is found through which water passes with difficulty, if at all. Above this, there is a stratum of water which moves from a higher to a lower level, and which varies in depth at different times according to the amount of precipitation, (rain or snow-fall), and according to the level of the nearest body of water toward which it flows. This stratum of water is termed the ground-water, and has within the last few years assumed considerable importance from its apparently close relations to the spread of certain of the infec-tious diseases. The direction of horizontal flow of the ground-water is al-ways toward the drainage-area of the district. Thus, it is usually toward lakes, rivers or the sea. Rains, or a rise in the river cause a rise in the ground-water, while long continued dry weather, or a low stage of the river which drains off the ground-water causes a fall in the latter. On the sea-coast the ground-water oscillations probably correspond with the tides. The writer is not aware of any observations made to determine this point. In Munich, where the ground-water flows toward the river Isar, which divides the city, it has been found that the annual range or oscillation (the difference between the highest and lowest level during the year) is ten feet, while the horizontal movement amounts to fifteen feet per day. In Buda