ON APHTHOUS DISEASE AMONG CATTLE. 635 
fact, these affections are chiefly generated during the most rainy 
seasons, in spring and autumn, in mountainous districts where the 
temperature is constantly varying, and in cold damp vallies. Our 
remarks only serve to confirm those of our predecessors. It was 
under similar circumstances, that is to say, after heavy rains that 
had fallen almost without intermission throughout the summer and 
greater part of the autumn, that the aphthae, which form the sub- 
ject of the present paper, made their appearance. 
Another cause, arising from the nature and quality of the ali- 
ments, in all probability contributed greatly towards their develop- 
ment. In this country cattle are fed on baked potatoes and the 
matters left after distillation. Last year the crops were in general 
very bad, the potatoes were damaged, and it was difficult to keep 
them, on account of their being impregnated wdth so much humid- 
ity. This food, acting on the organs in the same manner as the 
temperature and the climate, might it not have aided in modifying 
the whole organization in a manner sui generis, and inducing the 
aphthous affection 1 Be this opinion as it may, the fact is, that 
at all the different periods at which it has prevailed it has ap- 
peared under a similar conjunction of circumstances. 
In the excellent work published by our colleague, M. Lavigney, 
we have remarked that climate, temperature, locality, and manner 
of feeding, were without influence on the appearance of aphthae. 
Far be from us the thought of disputing such judicious observa- 
tions. In etiological questions, and especially in such as relate to 
epizootic diseases, all is in general latent, vague, uncertain, and 
subject to controversy, neither is it our intention to enter into a 
long discussion of this matter. We shall content ourselves with 
simply remarking, how frequently it happens that climacteric, local, 
and atmospheric actions, very different in appearance, will induce 
similar medical constitutions. Thus, for example, who is not aware 
that, at the same thermometrical degree, the proportion of humid- 
ity and electricity existing in the air will vary considerably ; and 
that in other cases, at unequal heights in the centigrade scale, a 
remarkable similarity will be found in the various atmospheric 
elements 1 
The nature of our habitual occupations does not give us time to 
investigate these meteorological researches, but in our leisure mo- 
ments we have established to our satisfaction the following fact, — 
namely, that the same medical constitution may be developed 
under different conditions of climate, temperature, and season. 
Symptomatology . — The course of this disease presents to our 
consideration four very distinct stages in all domesticated ani- 
mals. 
