westerly; in April, northerly; in May, southerly; in June, south-we. Serly; in July, westerly; in August, south-westerly, (easterly as often ;) in September, easterly; in October, south-westerly; in November, northerly; in December, north-westerly.

Dampness of the Air and Health.-Dry air as a rule is healthier than damp or humid air. Hence if rains continue long, or if fogs prevail for several days, the system suffers by the increased saturation. While oxygen and nitrogen and pure air itself are almost entirely diathermous, the absorptive power of moisture is very great. It seems that a molecule of aqueous vapor has sixteen thousand times the absorptive power of an atom of ox gen or of nitrogen; and carbonic acid, marsh gas, ammonia, etc., are also extremely absorptive. Now, when the sun shines on an atmosphere that is úry, his rays pass through it in all their power, but when the air is damp the rays are much weakened before they reach the earth. On the other hand, vhen the air is dry, the heat from the earth radiates into space much faste than when it is moist. The importance of these facts from a medical stand-point is very great. All the agents just mentioned as powerful absorbents of heat are found in greatest abundance near the earth; consequently they absorb a large amount of the heat radiated from the earth, which, it must be borne in mind, is the chief source of the heat diffused in the atmosphere. Usually over ten per cent. of the heat from this source is absorbed within ten feet of the ground.

On the northern Atlantic coast the south and east winds are, as a rule, moist winds; next come the northerly; next the south-west; next the west; next the north; and last the north-west. The sudden veering of a wind from a southerly to a northerly wind is usually attended with a precipitation of moisture; and the same is true of a sudden change of a northerly to an easterly.

Sea and Mountain Air Compared.-An able Italian physician, Dr. C. Alberto, in a recent work says: "The marine air produces the same benefit as that of the mountain, but each has a different modus efficiendi; the former acts more forcibly and energetically on the constitution which retains some robustness and internal resources to profit by it, while the second acts more gently, with slower efficacy, being thereby more suitable to the weaker, and less excitable organizations. From this important distinction, the conscientious physician who takes the safety of his patient much to heart, ought to be able to discriminate whether the alpine or the marine atmosphere is the better suited to the case he has before him."

Mutual Diffusion of Air.-The physical law known as that of "motual diffusion" plays an important part in all questions relating to the mixture of different gases, such as of oxygen, nitrogen, and carbor: acid, which make

up our atmosphere. By virtue of this law it occurs that two gases when brought together, no matter what their relative weights, become thoroughly mixed together, in proportions which are stated as being inversely as the square roots of their densities.

Carbonic acid is a gas so heavy that it may be decanted from one vessel into another; and hydrogen is so light that a balloon filled with it ascends, as we all know, into the air. Yet if a vessel filled with the latter be inverted over one containing the former, and a piece of membrane be placed between the mouths of the two, it will be found that, after a while, some of the carbonic acid has ascended into the upper vessel, and the hydrogen has descended in the lower one, and mingled with the carbonic acid. A mixture will be thus formed in both vessels.

It is the same in nature. Animals are perpetually exhaling carbonic acid into the atmosphere, and were it not for this wonderful property of "diffusion" a stratum of foul air would lie over the earth, and would possibly extinguish animal existence. The great value of connecting the air of our rooms with the free and purer air outside is, therefore, apparent.

Our Great Enemies, the Marshes.-M. Lombard, of Geneva, shows, from a great collection of statistical documents, that winter and spring are the seasons of greatest mortality in the north and center of Europe. In the south, on the contrary, summer and autumn are the most destructive seasons; but marsh miasm where it exists, transforms the period and character of the mortality. The same influence, as M. Simmoneau has shown, is the great obstruction to the acclimatization of Europeans in hot climates. It is to the perfect drainage of the soil that our efforts must be directed in both cases.

DISINFECTANTS-HOW TO PREPARE AND USE THEM.

Fresh Air and Sunlight.-First and always let in fresh air and sunlight, that they may purify every place they can reach. Open and dry all cellars and vaults, and keep the grounds and surfaces about dwellings as dry and clean as possible. Sedulously cultivate habits of the strictest cleanliness in person, clothing and habitation, indoor and out; as well in the cellar as in the parlor; as well in the darkest closet as in the hall; not neglecting a corner or a crevice in the whole building, keeping an eye to one point always, that wherever there is dampness there is disease, and that moral purity and filth in any form are absolutely incompatible.

Water. We have already seen the value of water as an absorbent and disinfectant. Dishes of water may be placed in any place required. Care should be used to remove the water frequently. Cold water is better than

warm for this purpose. A pailful of water in a freshly-painted room will often remove the sickening odor of the paint. Try it.

Charcoal.-Powdered charcoal is one of the best of disinfectants. It is very prompt in absorbing affluvia and gaseous bodies, as well as rendering harmless and even useful those bodies which are easily changed. Charcoal powder has long been used as a filter for putrid water. When the impurities are absorbed they come in contact with condensed oxygen gas, which exists in the pores of all charcoal which has been exposed to the air, and in this way become oxidized and destroyed. A layer of pulverized charcoal will prevent the escape of all offensive odor from any decomposing substance. Charcoal and Lime.-These may be mixed with notable advantage in many cases. This compound is known in the shops as "Calx powder." It is useful in absorbing putrid gases. Use it dry and fresh.

Clay. For many purposes dry clay is not only the cheapest but the best deodorant. It destroys or absorbs the foul odors, instead of partially overcoming them by substituting chlorine or coal tar in their place. The presence of clay has a great influence upon the health of communities. There are oftener cases of typhoid fever and dysentery on a sandy or alluvial soil than on a clay soil. This is probably owing to the fact that the water used is made pure by filtering through the clay soil, while in passing through sandy soil it retains to some extent its impurities, or adds to them.*

Quicklime and Gypsum.—Quicklime and gypsum or land-plaster are good absorbents, and may be used advantageously in damp places, cellars, gutters, etc. They should not, however, be used in drains, catch-basins, sewers, soil-pipes, etc.; nor where they are liable to be washed into such places, lest they, by decomposing soap-water, form lime-soap, and obstruct the passages.

Sifted Ashes are very useful in country water-closets, where they may be scattered as often as any odor is perceptible.

Surface Soil. Any surface soil or mold pulverized forms a convenient and effective absorbent and deodorizer for use in out-houses. The fresh dug earth is the best. It should be used in the same manner as above noted in the case of clay.

Fresh Stone-lime.-To absorb moisture and putrid fluids use fresh stone-lime finely broken; sprinkle it on the place to be dried, and 'n lamp rooms place a number of plates or pans filled with the lime powder.

Copperas. Common copperas, called sulphate of iron, in its crude state

There is another advantage in the country in using clay for privies. The removal of the contents is no longer a disgusting operation, while the farmer or gardener has a val. uable supply of fertilizing material for his grounds.

can be purchased for five cents a pound; this, dissolved in two gallons of water, and thrown over ill-smelling places, is one of the cheapest, simplest, and most convenient deodorizers, and is applicable to privies, sinks, gutters, and heaps of offal.

Chloride of Lime.-To give off chlorine, to absorb putrid effluvia, and to stop putrefaction, use chloride of lime; and if in cellars or close rooms the chlorine gas is wanted, pour strong vinegar or diluted sulphuric acid upon plates of chloride of lime occasionally, and add more of the chloride. We have known a large manufactory filled with deadly sewage air cleansed in a single half hour by throwing a half bushel of chloride of lime into the vaults from which the poisonous gas emanated. Chloride of lime is often deleterious in close dwellings because of the chlorine evolved. It may be used safely in the open atmosphere.

Salt and Lime Paste.-A cheap and available disinfectant and deodorizer is made by dissolving a bushel of salt in a barrel of water; then adding enough unslacked, that is, fresh lime, which has never been exposed to dampness, to make the whole into a thin paste, to be applied as often as necessary to all places yielding offensive smells, such as gutters, sinks, cesspools, etc. This is home-made chloride of lime.

Carbolic Acid.-A weak solution of carbolic acid may be used in saucers, or shallow earthen dishes; or a cloth saturated with it may be hung in the room where the offensive odor is suspected. In large cities the streets in the most densely populated wards have been watered on alternate days with a weak solution of carbolic acid with excellent results. There is no doubt that this excellent antiseptic and disinfectant has been very beneficial. The inhabitants of those streets have often expressed satisfaction at the freshness and removal of disagreeable smells which this acid produces, and they regard it as an addition to their comfort.

Salt and Nitrate of Lead.-Dissolve half a dram of nitrate of lead in a pint of boiling water, and two drams of common salt in a pail of water; then mix the two solutions and allow the sediment to settle. A cloth dipped in the liquid and hung up in the apartment is all that is required to purify the most fetid atmosphere. It is recommended for its cheapness, a pound of the materials costing about twenty-five cents. One pound of nitrate of lead, dissolved in a pailful of water, is excellent for sinks, sink-drains and vaults.

"Disinfecting Mixture."-Common salt, three ounces; black manganese, vil of vitriol, of each one ounce; water, two ounces. Carry this mixture in a cup through the apartments of the sick.

General Disinfecting Compound. For general disinfection the following compound is available and valuable, and far better than most of the patented

articles offered: Sulphate of iron, (copperas,) forty pounds; sulphate of lime, (gypsum or plaster,) fifty pounds; sulphate of zinc, (white vitriol,) seven pounds; powdered charcoal, two pounds. Mix well and scatter dry, or wet it in small quantities and make into balls ready for use. Where a liquid is needed, stir in water in the proportion of a pound of the powder or ball to a gallon of water, and sprinkle where needed.

Coffee as a Disinfectant.-Experiments with roasted coffee prove it to be a powerful means of rendering harmless and destroying animal and vegetable effluvia. A room in which meat in an advanced state of decomposition has been kept can be instantly deprived of all smell by simply carrying through it a coffee roaster containing a pound of newly-roasted coffee. The best mode of using the coffee is to dry the raw bean, pound it in a mortar; and then roast the powder on a moderately heated iron plate, until it becomes a dark brown color. Then sprinkle it in sinks and cesspools, or expose it on a plate in the room to be purified.

Sunflowers as Disinfectants.-Experiments in France and Holland have shown that sunflowers, when planted on an extensive scale, will neutralize the pernicious effects of exhalations from marshes. This plan has been tried with great success in the fenny districts near Rochefort, France; and the authorities of Holland assert that intermittent fever has wholly disappeared from districts where the sunflowers have been planted. It is not yet determined what effect the flower produces on the atmosphere—whether it generates oxygen, like other plants of rapid growth, or whether, like the coniferæ, it emits ozone, and thus destroys the organic germs of miasms that produce fever.

Boiling for Infected Clothing.-When foul clothing or infected things can be boiled, or have a boiling heat steadily applied and kept up for an hour, this is one of the simplest and best modes of disinfection. But until such high heat is actually applied to the infected things, some one of the disinfecting solutions must be used. A common steam tub, in a laundry or elsewhere, with a tight cover, is a good disinfecting vat. The clothing must be thrown into the water at boiling heat, and that temperature should be kept up for an hour.

water.

Soaking for Foul Clothing.-Soiled, impure garments may be put to soak in a half pound of sulphate of zinc (white vitriol) to three gallons of It will not stain or discolor most fabrics. One ounce of chloride of lead dissolved in a pint of hot water, and then a pailful of water added, into which a handful of common salt has been thrown, serves a similar purpose; also a half ounce of permanganate of potash to a gallon of water.

Boiling after Disinfection.—Permanganate of potassa may be used in disinfecting clothing and towels from cholera and fever patients during the