It is upward of eight-and-forty years since James Clarke of Edinburgh protested against close stables. He insisted that they were hot and foul, to a degree incompatible with health; and he strongly recommended that they should be aired in such a manner as to have them always cool and sweet. Previous to the publication of Clarke's work, people never thought of admitting fresh air into a stable; they had no notion of its use. In fact, they regarded it as highly pernicious, and did all they could to exclude it. In those times, the groom shut up his stable at night, and was careful to close every aperture by which a breath of fresh air might find admission. The keyhole and the threshold of the door were not forgotten. The horse was confined all night in a sort of hothouse, and in the morning the groom was delighted to find his stable warm as an oven. He did not perceive, or he did not notice, that the air was bad, charged with moisture, and with vapors more pernicious than moisture. It was oppressively warm, and that was enough for him. He knew nothing about its vitiation, or about its influence upon the horse's health. In a large crowded stable, where the horses were in constant and laborious work, there would be much disease.

Glanders, grease, mange, blindness, coughs, and broken wind, would prevail, varied occasionally by fatal inflammations. In another stable, containing fewer horses, and those doing little work, the principal diseases would be sore throats, bad eyes, swelled legs, and inflamed lungs, or frequent invasions of the influenza. But everything on earth would be blamed for these before a close stable.

Since 1788, when Clarke's work was published, there has been a constant outcry against hot, foul stables. Every veterinary writer who has had to treat of diseases, has blamed the hot stables for producing at least one half of them. So far as the influence of these writers has extended, they have produced some effect. A ventilated stable is not now a wonder; many are properly aired, and many more bear witness that ventilation has been attempted though not effected. Farm stables are, in general, pretty well aired, and it is probable they always were so. Carelessness is to be thanked for that'. Apertures which admit air are there by accident. The cavalry stables used to be shamefully close. Before veterinary sur-geons were appointed to the army, ignorance had leave to practise all its tricks. Professor Coleman introduced a system of ventilation which must have saved the government many thousands of pounds every year. Like many other salutary innovations, it was at first strongly resisted. Much evil was predicted; but diseases which used to destroy whole troops are now scarcely known in the army.

Much has been said and written about ventilation, and a good deal has been done to produce it in places where till lately it was never thought of. But still very many stables continue to be badly ventilated. The blame belongs chiefly to the architect. Few stable-builders think of providing apertures for the express purpose of ventilation. When reminded that the horse is a breathing animal, and that some provision must be made for letting him have fresh air, they display as much ignorance as if they had not learned their business. Mr. Lyon's new stables were ventilated from the beginning. Each stable contains sixteen horses, and two apertures were placed at the highest part of the building. They were very well placed, indeed just where they should be, for carrying off the heated and foul air. But their size; Each pipe was exactly three inches and a half square! These two holes would hardly ventilate a stage-coach,, or an omnibus, and yet they were intended for sixteen horses. There was no other opening whatever; the windows would not move, and the doors were as closely fitted as they could be.

The architect may be ignorant, but the owner of the horse ought to know better. The wealthy and well-informed proprietors of large coaching and posting studs, are sufficiently alive to the importance of ventilation. Those by whom it is neglected are soon taught, and in a way that is not easily forgotten. But there are many who still oppose ventilation; some are indifferent about it, and very few know how it ought to be produced.

Much of the opposition to ventilation has arisen from an error, very common among those who recommend it. They invariably confound a hot stable with a foul one. The two words, hot and foul, are seldom separated. The stable is spoken of as if it could not be hot without being foul; and the evils which spring only from foulness are attributed to heat. Hence, those who happen to have a stable warm, o' it may be hot, and at the same time clean, are very apt o oppose the practice of ventilation. Their horses do as well as those in colder stables, and, it may be, they do much better. One will say, I find the practice of airing stables does no good; it is founded upon theory, it won't stand the test of experience. My horses look as well again as those of my neighbor over the way, and my stable is like an oven compared to his. This may be quite true. To look well \ horse must be kept warm; but to be well, fit to do all the work a horse can be made to do, he must have pure air. We are not contending, or we should not be contending, against a warm, but against a foul stable. In general, it so happens that the air in becoming warm also becomes impure. But this is not a. necessary consequence.

Air may be cold and at the same time quite unfit for breathing, or it may be hot and yet perfectly free from impurity. There may be stables in which the atmosphere is perniciously hot; but I do not think 1 have ever seen them. I have not been able to trace a disease arising from warm or hot stabling. [This is a great error, for nothing is more easily susceptible of proof, than that horses housed in very warm stables are much more liable to take cold when out in a raw wind or during the winter season, than those kept in a lower atmosphere. Dangerous inflammatory complaints are also more likely to follow colds take by horses when too warmly stabled or clothed.] But every year affords innumerable examples of what mischief can be done by a foul stable. Of course these foul stables are always hot; but, in my belief, it is the impure, not the heated air, from which disease arises. Many stables remarkably warm are remarkably healthy. It is important to make this distinction. The horse can be kept warm without being poisoned with foul air. And, among stablemen, it is so well known that warmth is congenial to the horse, that it improves his appearance, and gives him greater vigor, that it is perfectly useless to offer any opposition to it. Practice will always prevail over theory.

We ought not to oppose warmth, but the means by which warmth is given. The horse should be kept comfortably warm, but he must have pure air. A cold stable is not so dangerous as a foul one.