with warm air in any proportion it may be proper to adopt in producing a sudorific effect, while any admixture of volatile ingredients can be communicated to the passing air, the skin being exposed continuously at the same time, or as frequently as may be desired, to ablution with a warm shower-bath. The hands and body are not impeded from the fullest opportunity of using friction-cloths. The whole surface of the lungs and skin is subjected in the bath to the free oxidation of the air, and warm and palatable diluents being drunk copiously there to sustain the strength and promote perspiration, a quantity of water passes through the blood in a short time, which has the most wholesome and purifying influence. Care must be taken to reduce the circulation of the blood slowly in an adjoining warm room, after leaving this bath, before exposure to the external atmosphere.

The pulls shown on either side of the chair regulate the admission of air, the discharge of vitiated air, the ingress of steam, and the temperature of the water used as a shower-bath.

By these varied means, much additional power is given to the steambath, while the offensive atmosphere attendant on its ordinary use is entirely obviated. Such a steam-bath, in its simplest form, should not cost more than a few cents each time it is used, where it is provided for numbers.

DRY AND MOIST AIR.

A constant cough attacks an invalid in frosty weather, while the skin feels harsh and dry, and these effects are increased when a stove in the room he occupies is in use, though an iron basin containing water is placed upon it.

Let a

What remedy is available? Let a larger surface of water be exposed to heat, with a view of adding more moisture to the air. well-tinned or porcellaneous vessel be substituted for the iron-vessel containing the water. If the complaints mentioned are not removed, try the effect of boiling water, and causing a free discharge of steam into the room, till it begins to condense rapidly, like hoar-frost on the windows.

Where any source of pure steam is available in the vicinity, a small branch-pipe from the boiler may be used for its introduction.

In hotels, lodging-houses, or other crowded habitations, where boilers are always available, the steam has often an offensive oily odor. It can then, at all events, be used in heating the porcellaneous or other vessel from which the purer steam can be prepared. In large buildings, where there is the opportunity, moisture conveyed to air by a steam-pipe should be mingled with the ventilating current of supply proceeding to any apartment, being then more generally diffused.

Where the wet-bulb hygrometer is used, Fig. 42, an atmosphere that is so charged with moisture that the ordinary thermometer indicates a temperature about five degrees higher than the thermometer having the bulb covered with muslin, and moistened, is found to be generally acceptable in England. In this country, the atmosphere being usually much dryer, or, in other words, having a greater dissolving power, it may be desirable not to give so much moisture as may be required to produce a similar quality of air in this respect. A nearer approximation to it, however, would in all habitations heated with little addition of moisture, produce a great improvement, by reducing excessive evaporation from the surface of the lungs as well as from the surface of the body.

If, on the other hand, air be too moist, and the temperature be not high, then nothing corrects this evil so conveniently as the communication of heat. It may not actually remove the moisture, but it gives the air a greater dissolving and retaining power, producing therefore an equivalent effect.

It is rarely that measures are resorted to for the actual removal of moisture, in consequence of the expense, except when this is effected by cold, or by the absorbing power of quick-lime, an agent of great value for this purpose in the sick-chamber, in rooms that are occupied almost as soon as they are plastered, and in damp-cellars.

VENTILATION OF HOTELS.-NOTES IN REFERENCE TO THE NATIONAL HOTEL DISEASE AT WASHINGTON.

In the largest mansions, palatial structures and hotels, opportunities occur for treating them to some extent in the same manner as public buildings, more especially the dining-room, the ball-room, or any apartment appropriated for public meetings or other assemblies. As it is not intended, however, that these pages should include the consideration of public buildings, it will be sufficient here to give an outline of some points not so specially mentioned hitherto, and to state that though a central ventilating power is generally the most desirable in individual buildings, cases constantly occur where it may not be an object to effect the most extensive centralization practicable, and in which therefore a few independent shafts or ventilating turrets may be advantageously introduced as a substitute.

There are also many instances where an engine may be used instead of shafts as a moving power for forced or systematic ventilation, though apertures for discharge should always be provided under any circumstances. Without these, vitiated air may often be driven from one room to another and not be discharged at a proper place; or it

may even recoil in one portion of an apartment, while fresh air is ascending in another.

It cannot be too strongly represented, that the greater the number of rooms, halls, and passages in any building, the greater the annoyance from vitiated air or from local and offensive currents, if a sufficient supply of air be not provided, and a well-organized escape for the vitiated air.

Further, the greatest perfection in ventilation is always accompanied by an ingress and egress, or supply and discharge, so balanced that there is no objectionable current at doors. If an objectionable current move outwards, then the supply forced in by the external air or by any instrument used for this purpose, must be too great, unless the discharge of the vitiated air be too small. On the other hand, if the offensive current proceeds inwards, then the supply of external air must be too small, or the action of the shaft or channel by which the vitiated air is discharged too great.

A little reflection on these two examples will simplify many cases that are apt to be very perplexing to those unaccustomed to enter on such questions. Nor is it possible in complicated buildings, such as large hotels, always to avoid such difficulties, where they have been built without regard to systematic ventilation.

There are four evils, however, to which many hotels are peculiarly subject, that can be entirely avoided with proper attention to them.

1. The accumulation of vitiated air in the public apartments, arising from the ineffective discharge of the products of respiration, of the combustion of gas, and from the presence of excessive moisture, or vitiated air in the refreshment rooms.

2. The prevalence of tobacco-smoke, an evil from which many hotels. are remarkably free.

For the entire and absolute control of the vitiated air from smokingrooms, a ventilating flue should be made to withdraw the smoke, so that it cannot enter into any passages, stairs, or other apartments where its use is not allowed.

3. Emanations from kitchens and sculleries.

Without a proper ventilating arrangement these can never be entirely excluded. Even if placed in external buildings the wind may drift them upon the hotel.

4. Vitiated air from closets, drains, and sewers.

The control and absolute exclusion of all vitiated air from these sources is equally indispensable to health and comfort.

The noted case of the National Hotel at Washington, where so many hundreds suffered very lately, was not unconnected with the

condition of the ventilation. Whether other causes contributed or not, is a question that is not entered on here; recent facts and statements that have been made on this point may leave this an open question till the whole of the evidence on the subject shall be published and compared, but in the mean time personal observations in this Hotel at the time referred to gave proof that there was, in one part of the hotel at least, a discharge of vitiated air from drains of so intense a character that it produced instantaneous vomiting on some occasions, and affected numbers in a less degree at the moment, who were nevertheless attacked at a subsequent period.

The report of the chairman of the Board of Health at Washingion, Dr. King Stone, as well as the Report of the Committee of the Academy of Medicine of New York on this subject, fully express the conviction of the important effect produced by the emanations from the drains, and attribute the National Hotel Disease to this cause. No other cause has as yet been proved to have been in operation; and even if it were, it would in no way alter the conviction entertained, that the emanations from the drains constituted an evil of great magnitude, and capable of producing the most disastrous results.

Let it be recollected that there are no deleterious gases that can arise from the admixture of chemicals that may meet in obstructed drains and sewers, that may not find their way into hotels, houses, and other buildings, as well as the products of putrefaction from animal and vegetable matters. Sewers may discharge there the products formed at the distance of miles, particularly if they be trapped so as to exclude the access of air in the streets. And who can estimate the emanations that may not proceed from such sources, when they arise from chemicals discharged from a manufactory, an apothecary's store, a paint shop, a telegraph office, or the poisoned remains of animals that may have accumulated in the sewers? Further, the very cement or mortar may imbibe materials that discharge sulphuretted or arsenuretted hydrogen from compound mixtures on fermentation, or from the action of an acid, and these find their way, by a retrograde current in the drains and sewers, to any building connected with them, where the drains have been injured and the traps rendered ineffective.*

Lastly, it should not be forgotten that if one or two hundred thousand dollars be the probable amount of loss to the individual sufferers

* We understand that Dr. Reid considers it not improbable, if the statements made as to the use of arsenic on the premises are correct, that the effect of the malaria from the drains may, under certain circumstances, have been greatly aggravated by arsenuretted hydrogen gas; though no arsenic may have been dissolved by the water in use at the hotel, it may have been present in unlimited quantities in the obstructed draina

and proprietors, the whole of this sum might probably have been saved, to say nothing of loss of life and loss of occupation to numbers interested, had the hotel been ventilated as had been suggested during the preceding year, and again recommended before the disease there assumed such a condition that the medical authorities deemed it indispensable that it should be closed. Even one or two hundred dollars would have removed the worst evils arising from the drains at the moment, by discharging the gaseous products from them by an independent channel, till the greater and general evil proceeding from obstructed sewers could have been removed. Can a more striking example be found of the importance of hygiene and the chemistry of daily life being made subjects of elementary study in all schools, public or private? Those most largely interested were not impressed with the importance of the ventilation previously recommended, till it was too late to attempt to keep the hotel open longer at the period mentioned.

The improvement of numerous hotels has been very marked in recent years in the great majority of modern cities; but an instance such as the National Hotel at Washington has presented, and the results of the inquiries instituted on this subject, point out emphatically how much is yet to be done in improving the hygiene of cities as well as of individual habitations. Nor have such inquiries a local importance alone; it would be difficult to select any cities without finding some hotels presenting parallel evils, arising from drains and sewers, however inferior generally in point of intensity.

If the ordinary condition of the atmosphere at Paris be examined, of the air on the banks of the Thames at London, or over a large portion of Berlin, abundant evidence will be obtained of the effect of causes that have been increasing for ages in deteriorating the atmosphere of these capitals. The most Herculean labors, as well as the expenditure of millions, can alone place them in that position which, with the aid of public opinion and of parliamentary and municipal authority, they may at last attain.

There are few remarks in the preceding chapters that do not apply to hotels as well as other buildings, particularly those on ventilating shafts, lighting, heating, and cooling, and the details as to the ingress and egress of air at entrances, passages, stairs, and individual apartments.

The accompanying Fig. 79 explains the general suite of arrangements which it is desirable to introduce in crowded hotels. Air, from the least objectionable source, is conveyed by one or two channels, a and b, to general reservoirs or distributing channels c, c. Steam,