Liebig, with expressions of astonishment, that at his table at the time, a regular deficiency occurred in certain dishes, especially farinaceous dishes, puddings, &c., which was an unheard of occurrence in a house in which the amount and proportion of the dishes for a given number of persons had been for years fixed and known. Now, this dining-hall was filled with "friends of peace," all of whom belonged to the temperance unions, and drank no wine. Herr Sag, the landlord, observed that those who take no wine always eat more in proportion. In wine countries, therefore, the price of the wine is always included in that of the dinner, and it is considered just that in hotels people should pay for wine even when they drink none thus reversing the old condition, "O, monstrous! but one half-pennyworth of bread to this intolerable deal of sack !"-Shaks

peare.

Tea, coffee, and chocolate differ from wine in their action on the vital processes. We know very little of the physiological effects of these drinks. It is very probable, however, that the use of them, as a part of food, depends on the exciting and vivifying action which they have in common with soup. These effects are usually ascribed to the presence of theine in tea, and caffeine in coffee, both of the same nature; and it is a curious fact that these substances belong to a class of organic bases, in which theine may be said to be the beginning, quinine the centre, and at the top of the scale brucine, with the formidable, murderous strychnine. In fact, the medicinal and poisonous organic bases contain for one equivalent of nitrogen more than eight equivalents of carbon, which are those of the blood. Theine or caffeine, and the bodies resembling them, which may be taken without injury-all, on the other hand, contain for the same amount of nitrogen less carbon than the constituents of the blood.

The infusion of tea differs from that of coffee by containing iron and manganese; it is, therefore, a beverage which contains the active ingredients of the most powerful mineral springs, and however small the amount of iron may be which we daily take in this form, it cannot be destitute of influence on the vital processes. Coffee contains copper; we once saw the estimate of the quantity of copper in lbs. thus swallowed by the coffee drinkers of Europe, and although we have forgotten the amount, we can attest its startling magnitude.

By the presence of empyreumatic substances, roasted coffee acquires the property of checking those processes of solution and decomposition which are begun and kept up by ferments. All empyreumatic bodies oppose fermentation and putrefaction; thus smoked flesh is less digestible than that which is only salted. The consequence is, that persons of weak or sensitive organs will perceive, if they attend to it, that a cup of strong coffee after dinner instantly checks digestion. It is only when the absorption and removal of it has been effected that relief is felt. For strong digestive powers, coffee after eating, serves, from the same cause, to

moderate the activity of the stomach, exalted beyond a certain limit by wine and spirits. This may explain the instinct which suggests the cup of coffee after dinner. For the most part it does more harm than good. Besides, the habit once established, must be continued, or a severe nervous headache will be the consequence. But this consequence of the cessation of the drink rarely lasts longer than the first evening after discontinuance.

Tea has not the same power of checking digestion; on the contrary, it increases the peristaltic motions of the intestines; and this is sometimes shown in producing nausea, especially when strong tea is taken by a fasting person. Coffee diminishes the excretion of urea, and consequently exercises an action in the change of matter, opposite to that of wine. It also acts powerfully on the kidneys, whose secretion it greatly increases. It must, therefore, so far, tend to impoverish the blood. It is well known that both tea and coffee prevent or retard sleep; they must therefore act on the brain. In fact, they are medicines.

Cocoa or chocolate is a great improvement upon tea and coffee in the matter of nutriment or the production of force, besides being deficient in ingredients that act on the nervous system. A glass of water taken after drinking it, will dispel the heavy sensation experienced by some persons after using chocolate, which, however, may be otherwise prevented by mixing strong coffee with it—one part of the latter to two of the former-which produces a very pleasant beverage, combining the aroma of the coffee with the nutriment of the chocolate.

However excellent the food, however, and indeed, whatever may be the other good conditions of health, there is no dispensing with pure air. When the inspired air is the same as that which is exhaled, the object of respiration is no longer attained. The expired air is used air, which cannot a second time perform the same function in the lungs. The venous blood is no longer changed into arterial; difficulty of breathing, and finally, suffocation, soon come on, just as if the mouth and nose were closed. In this case, death is determined by two causes. One is, beyond doubt, the deficiency of oxygen; the other is the presence of carbonic acid, by the presence of which the absorption of oxygen is impeded.

Experiments, however, have proved that the lungs are not the true source of animal heat, like a fire-place, as is commonly supposed; but that, in the arterial blood, a current of oxygen is conveyed through the body, which, in its passage through the minuter vessels, causes the oxidation or combustion, among which is carbonic acid, and consequently gives rise to a disengagement of heat.

The army regulations provide that each soldier shall have secured to him in permanent barracks 600 cubic feet of air; in wooden huts 400; in hospital wards in the tropics 1,500; in wooden hospitals at home 600; and the ventilation must be so perfect that the 600 cubic feet of air shall be changed twice every hour. But Dr. Parkes found from experiments he made, that to keep the air nearly

pure and free from the fetid smell of organic matter, nearly double this quantity is required, and his observations are confirmed by the experiments of others. General Morin requires to be supplied per head, in temperate climates, as follows:-In barracks, 1,059 cubic feet by day, and 2,118 by night; in hospitals 2,825 cubic feet by day and night, and nearly double this quantity when the dressing of wounds is going on, and finally, 5,650 cubic feet during epidemics. This is the minimum quantity necessary; where it is possible it is advisable to have much more than this in hospitals, and of course equally in bed-rooms in private houses; it is advisable in cases of typhus fever, pycemia, or erysipelas, to give the patient an unlimited supply of fresh air.

Such are the suggestions of those who have investigated this important subject; but we may observe that the air of a room may be rather too fresh to admit of comfortable sleep, especially if it be cold. The inhaling of a little carbonic acid gas seems natural to secure sound sleep in man as well as in other animals. The hen pockets her head beneath her wing; the dog jams his nostrils under his paws or his belly; and children bury their heads under the bed clothes. When we have found sleep rather slow in coming, we have soon secured it by pulling the sheet over our head.

In a hot country, where active exercise is almost impossible, pure air is more essential than in temperate climates, where the quantity of oxygen absorbed, capable of neutralising the impurities it contains, rests very much at the will of each individual. Unfortunately, the air of the large cities, towns, and villages of India is very far from being pure, indeed, considering the want of cleanliness on the part of the natives, and the bad sanitary arrangements, the wonder is that epidemics are not more frequent than they are. According to Mr. Clark, the ventilation of barracks in India is too little, and the diet of the army too large. As regards the latter, we acknowledge that we are surprised at its amount when we compare it with the dietary which is considered sufficient for our troops in this country, however cold the weather may be. In a country so hot as India, it must surely be too much to give a man daily of meat 1 lb., bread 1 lb., vegetables 1 lb., rice 4 ounces, salt 1 ounce. recommending the substitution of dall, and such dried fruits as apricots, raisins, plums, and dates in lieu of a portion of the meat, he says: "The greatest defect in the diet of the European soldier, is the want of a due amount of vegetables. If the want of a plentiful supply of this most essential article of diet is the cause of disease in other groups of individuals, why should it not be equally so among the soldiers? In fact they are so badly supplied with vegetables, that there can be no doubt that dysentery, diarrhoea, and other complaints which very often assume a scorbutic character, may, in a great measure, be attributed to this cause."

After

Not only is the air rendered impure by the presence of carbonic acid, but it is tainted with organic matter given off by the lungs, and from particles thrown off from the surface of the body, as well

as by soot, dust, and the endless list of substances raised aloft by the wind, and which must be inhaled at every breath we draw. We do not yet know how certain diseases are propagated, but it is more than probable that erysipelas, hospital gangrene, and other diseases deemed contagious, are caused by the inhaling of air in which these organic particles are floating. At all times the air of rooms is loaded with particles of matter, which can be rendered visible by merely closing the shutters and admitting a ray of sunshine, when they are seen revolving in such profusion that the air acquires an appearance of solidity; indeed, it seems that the beam of light positively resists the curling smoke of tobacco when puffed against it in such circumstances. The experiment is very interesting.

Now, considering that it is impossible to draw a single breath without bringing myriads of these particles into direct contact with the lungs, the cells of which present a surface variously estimated at from ten to upwards of twenty square feet, we cannot but marvel at our being able to breathe such an atmosphere with apparent impunity for so many years. This impunity, however, can only be apparent, the effect telling in the long run, either in posi tive lung disease or general debility. The almost entire absence of these impurities from the air at the seaside, and in the country generally, may account for the great change in the feelings of the inhabitants of towns after a sojourn of only twenty-four hours in it. It has been shown that in the dust collected in a hospital ward, from thirty-six to forty-six per cent of organic matter existed, which, when burnt, gave out an odour of horn, and when moistened and allowed to decompose gave out a fetid, putrid smell. Dr. Parkes discovered large quantities of similar matter from the skin, and perhaps, as he says, from the mouth, in the air of various barracks and military hospitals. The possibility of a direct transference from body to body of "cells" or the germs of disease, undergoing special chemical changes, is thus placed beyond doubt, and the doctrine of contagion receives an additional elucidation.

Such are a few of the suggestions of chemistry to Military men. Under many circumstances, it desolves upon officers to do that which is performed by the regimental surgeon in barracks or in large camps, and at all times such knowledge will qualify them to see how closely the treatment of their men approaches the standard calculated to raise them to the highest efficiency as regards their physical power, and suggest the means whereby they may, through their own exertions, promote their happiness aud enjoyment.*

* Full information on all the subjects touched upon in this article, will be found in Dr. Parkes' Manual of Hygiene, a work whieh must be invaluable to every officer. A comprehensive summary of the work will be found in the Number for December 1864, of the United Service Magazine, and valuable remarks respecting the Hygiene of the Army in India," in the Number for January 1865. Liebig's most interesting, "Familiar Letters on Chemistry" would be an appropriate addition to the library of every officer.

NAVAL IMPROVEMENTS.

We were very comfortably seated in one of the capacious carriages which are now so common on the main lines of railway, and had made up our minds to have a quiet nap during the remainder of our journey, when two passengers got into the compartment, and soon began discussing the evidence taken before the police magistrate, and the two nautical assessors, respecting the melancholy loss of the steam-ship London. One of our companions seemed to attach most importance to the build and construction of the ship, while the other maintained that everything depended on the manner in which she was handled. This led the conversation to the state and condition of the crew, and much surprise was expressed at the practice which prevails in the merchant service of receiving the ships' company only on the point of sailing, and in the case of vessels sailing from London after the vessel has left the docks and within a few minutes of passing Gravesend. But this practice, bad though it must be, is not so bad as that of allowing the men to go on board in a state of drunkenness, and to our minds it is almost marvellous that many more of the merchant vessels which leave England for the colonies and foreign ports, do not get into trouble immediately on their quitting port. In the Navy snch things are fortunately not known, and when a man-of-war goes to sea for the first time, the captain and officers not only have a place for every man, but they take care that every man is in his place, and that he has a specific duty assigned to him.

Our companions called our attention to the advantages which the men of the Royal Navy possess over those of the Mercantile marine; alluding especially to the lightness of the work in the Imperial Service as compared with that in the Merchant navy; they might have referred also to the difference in the quality of their food, in their berthing, and their pay; for, taking everything into consideration, we have no doubt but that the naval seaman receives either directly or indirectly more money, or money's value than his brother in the private service. This assertion would not have held good a few years ago, when it was no doubt much better for a sailor to enter the merchants' employment, than to serve the Queen. But the fact is, that the condition of the one has been gradually improved, while that of the other has not materially altered. The movement which was commenced soon after the Syrian affair-when so much difficulty was experienced in manning the fleet, that several of the ships had to go to the scene of action with reduced complements-has been kept alive, and alterations have been made from time to time, which have by degrees raised the Navy to its present satisfactory condition. The vast improvements made in the construction of our ships would have been of