The deterioration of air by consumption of oxygen, and addition of carbon, is produced entirely by breathing; and when carried beyond a certain point, debility, or disease, or death, one or all, must be the result. But the air of a close stable is vitiated by other means. There are emanations from the surface of the body, from the dung, and from the urine. The effluvia, arising from these, mingle with the air, and contaminate it, till it acquires the power of exciting disease When the dung and urine are allowed to accumulate day after day, till the horse lies upon a bed of rotting litter, the air becomes still more seriously tainted. When first entered in the morning, the pungent vapors of these close stables are almost suffocating. Even after the doors have been open all day, there are many corners where the air is always foul. The acrid odor which irritates the eyes and nostrils, is chiefly or entirely composed of ammonia. It is given out by the evacuations, particularly after they have begun to ferment, to rot. [The best substance to sweeten and purify the atmosphere in stables, and for fixing the ammonia arising so strongly from horse urine in particular, as well as from all animal evacuation, is charcoal-dust scattered over the floors, among the litter, and on the dung-heap. Plaster of Paris is an excellent thing; also sulphuric acid diluted with about fifty per cent, of water, and sprinkled on the litter.

All these substances add to the value of the manure, more especially the charcoal-dust, and it has the further advantage of being cheapest, and usually the most easily obtained.]

The chymist can discover the carbonic acid and the am-moniacal vapor which mingle with the air of a close stable. By examining the air after a certain manner, he not only ascertains the presence of these gases, but he also measures their quantity. It has, however, been supposed that the air often contains foreign matters, whose existence can not be shown by any chymical process. There is reason to believe, that whenever a large number of animals are crowded together, and compelled to breathe and rebreathe the same air several times, an aerial poison is generated, having power to produce certain diseases. Professor Coleman is of opinion, that glanders in the horse, rot in sheep, husk in swine, typhus fever, and some other diseases of the human species, are all occasionally produced in this way. It is certain that health can not be maintained in an atmosphere greatly vitiated; but whether the disease arise merely from a deficient supply of oxygen, or from some peculiar poison generated during respiration and perspiration, can not be positively known Chymists, indeed, deny the existence of this animal poison They can not find it; but it does not, therefore, follow that there is none. To their tests the matter of glanders and that of strangles appear to be perfectly similar.

That they are not the same, however, is proved by applying them to a living being. The air may contain a poison which no test merely chymical can detect.

The Evils of an Impure Atmosphere, vary according to several circumstances. The ammoniacal vapor is injurious to the eyes, to the nostrils, and the throat. Stables that are both close and filthy, are notorious for producing blindness, coughs, and inflammation of the nostrils; these arise from acrid vapors alone. They are most common in those dirty hovels where the dung and the urine are allowed to accumulate for weeks together. The air of a stable may be con-animated by union with ammoniacal vapor, and yet be tolerably pure in other respects. It may never be greatly deficient in oxygen; but when the stable is so close that the supply of oxygen is deficient, other evils are added to those arising from acrid vapors. Disease, in a visible form, may not be the immediate result. The horses may perform their work and take their food, but they do not look well, and they have not the vigor of robust health. Some are lean, hidebound, having a dead dry coat; some have swelled legs, some mange, and some grease. All are spiritless, lazy at work, and soon fatigued. They may have the best of food, and plenty of it, and their work may not be very laborious; yet they always look as if half-starved, or shamefully overwrought.

When the influenza comes among them, it spreads fast, and is difficult to treat. Every now and then one or two of the horses becomes glandered and farcied.

Stables are close in various degrees, and it is only in the closest that their worst evils are experienced. But bad air is most pernicious when the horses stand long in the stable, when the food is bad, and when the work is laborious. Hence it is chiefly in the stables occupied by coaching and boat-horses, that the effects of a foul atmosphere are most decisively announced. Other stables, such as those used for carriage-horses, hunters, racers, and roadsters, may be equally ill-ventilated; yet the evils are not so visible, nor of the same kind; coughs, inflamed lungs a marked liability to influenza, and general delicacy of constitution, are among the most serious consequences. But the two cases are different. These valuable horses have not so much need for fresh air; they are not required to perform half the work of a stage-coach horse; they are much better attended to, particularly after work. The stable is kept cleaner; the air is not contaminated by rotting litter, and, in general, the food of these horses is of the best quality. Many farm and cart-horse stables are destitute of efficient ventilation, but the horses do not suffer so much as might be expected.

Their slow work does not demand a constant supply of the purest air; and, compared with the fast-working coach-horse, they are but. a very short time in the stable. A coach-horse who does his work in one hour, must suffer more than the other, who is in the open air perhaps ten hours out of the twenty-four.

When a deficient supply of air, hard work, and bad food, happen to operate in combination, the ravages of disease are dreadful. Glanders and the influenza burst among the horses; and they make brief work of it. For a long time the horses may appear to suffer little inconvenience. They may be lean, shamefully lean, unfit for full work, and many may become unable to continue at any work. Several may have diabetes, and many be troubled with bad coughs. But until a sickly season prevails, or until some other circumstance occurs to render the horses more than usually susceptible of the evils arising from the combined influence of bad air, bad food, and hard work, there is nothing to excite any alarm. They manage, with some difficulty, to perform their allotted task, though they never look as if they were fit for it. At last the influenza appears, or a horse suddenly displays all the symptoms of glanders. One after another is taken ill in rapid succession, and death follows death until the stables are half emp tied, or until the entire stud is swept away. The proprietor begins to look about him. It is time for him to know that God has not given him absolute and unconditional control, over his fellow-tenants of the earth.

Oppression has wide dominions, but there are limits which can not be passed. Continued suffering terminates in death.