384 
ON THE EXTERNAL CAUSES OF DISEASE. 
body; the blood is propelled with increased momentum to the 
heart: and supposing the body to be now emerged, the reaction 
of the heart, sending back the blood to the surface, diffuses a 
genial warmth, and removes the stricture; but if the stricture 
continue, this effort of nature to relieve herself will terminate in 
general inflammation. 
Such is the effect of sudden cold when its application is uni¬ 
versal ; but should the application be partial, what will then be 
the consequence ? The effect already stated will be partial . 
Constriction will take place in the extreme vessels subjected to 
the access of cold, and the blood will be propelled with increased 
momentum into the adjoining vessels, where tension will prove a 
stimulus. Many examples of this might be given. In the case 
of catarrh arising from sleeping in cold damp sheets, the person, 
upon getting into bed, usually feels no very uncomfortable sen¬ 
sation of cold : he soon acquires the usual genial heat of the 
bed, and falls into the state of sleep ; but in the morning awakes 
with a confused perception of disorder, which, in the course of 
the day, puts on a characteristic form. Here, then, is the ap¬ 
plication of cold and moisture producing disease without being 
accompanied or followed by external heat. Again; a reaper, 
reeking with sweat, lies down to sleep upon the grass : the injury 
is perceived before the cold has alternated with heat, although 
the subsequent application of heat, in proportion to its intensity, 
will increase the disease. As an external agent, heat is, without 
doubt, by far the most frequent exciting cause, and cold appears 
to be that which predisposes the oftenest; yet the application of 
cold, in the instance we have mentioned, has a directly exciting 
effect. On the whole, then, it appears, that when the change is 
gradual, nature, between wide extremes, can accommodate her¬ 
self to her condition ; but that when the change is partial, sud¬ 
den, and continued, it generates disease. 
But to return more immediately to our subject, which we fear 
is not sufficiently “ dovetailed” to suit the tastes of the readers 
of The Veterinarian. The plan we would recommend for 
the proper ventilating of a stable, is one that has for its object 
that of keeping up that degree of warmth which is requisite for 
the health of the animal, combined with a free circulation of at¬ 
mospheric air. 
The situation of a stable should be dry and elevated; a 
northern aspect is, perhaps, the most desirable. The height 
within should be, at least, twelve feet, and the walls of a suffi¬ 
cient substance to prevent, as effectually as possible, either the 
heat of summer or the cold in winter from affecting the temper¬ 
ature of the interior. The floors should be made either ot large 
