ON THE EXTERNAL CAUSES OF DISEASE. 
377 
affect its vital principle. Most persons are aware of the neces¬ 
sity of a due supply of air, but they are ignorant of the method 
of obtaining it in their stables. The door is oftentimes the 
only entrance for fresh air; others have windows, which are 
shut and opened at the pleasure of the groom. But the noxious 
vapours arising from an animal’s body can be little affected by 
such means. Every animal has an atmosphere of its own, heated 
by the warmth of his body, which can only be dissipated by 
motion in the circumambient air. It is the stagnant atmosphere 
that is most to be dreaded. To the poor benumbed beast, ex¬ 
posed to an inclement wintry sky, who instinctively collects his 
limbs into an attitude as fixed as marble by the sheltered side of 
a hedge, lest, by their motion, he should dissipate the stratum 
of warmer air immediately surrounding his body, a stagnant atmos¬ 
phere is desirable, not only by moderating the painful sensation of 
cold, but by preventing the dissipation of that degree of heat which 
is necessary for the preservation of the vital principle. But let 
circumstances be reversed, and instead of the miserable half-fed 
beast exposed to the severities of winter, let us picture to our¬ 
selves the horses on board of one of the transports, in the expe¬ 
dition to Quiberon ; how r grateful to their feelings would have 
been a current of fresh air. Circumstanced as they were placed, 
the sufferings of these poor animals must have been dreadful; 
the hatchways being closed down, they were almost suffocated. 
We have been informed, that they have been observed drawing 
their breath with all the laborious and anxious efforts for life 
which are seen in expiring animals, subjected by experiment in 
the exhausted receiver of an air-pump. 
Mr. Coleman informs us, in his lectures, that the consequences 
of this were, that almost all of them disembarked either 
glandered or farcied; and the few that escaped these fatal dis¬ 
eases were affected with grease, mange, ophthalmia, &c. &c. 
In long-continued calms, in which there is a stagnation of the 
air, and during which the heated and contaminated atmosphere 
is not replaced by fresh and purer air, fevers and diseases of 
various kinds are observed to be more prevalent than at any 
other time. For several weeks before the plague broke out in 
London in 1665, there was an uninterrupted calm, so that there 
was not sufficient motion in the air to turn avane # . 
* Since writing the above, we have had the pleasure of reading some ob¬ 
servations of Dr. Prout, in his Bridgwater Treatise on the Effects of Foreign 
Bodies in the Atmosphere, which so strongly confirm what we have writ¬ 
ten on the subject, that we have been induced to transcribe them :— 
“In the year 1782, and still more in the jear following, a remarkable 
haze extended over the w hole of Europe. Seen in mass, this haze was of 
