THE VETERINARIAN AS A MEMBER OF SOCIETY. 
Ill 
of life which are created, and to which the domesticated animals 
are forced to submit, bring into play new influences, which mod¬ 
ify their constitutions in such a manner as to render them sus¬ 
ceptible of general maladies of a new type and of a character 
corresponding to the artificial causes which induced tlmm. 
It is only by taking this view of the subject that we can ac¬ 
count for the appearance of diseases which a few centuries ago 
were, so far as present accessible evidence leads us to believe, 
unknown. For instance, according to all written testimony, the 
foot-and-mouth disease of ruminants and swine is a comparatively 
modern affection ; so also is the so-called venereal disease of 
horses; the typhoid fever, cholera or measles of pigs, and other 
maladies of a similar kind. The variola, a most destructive dis¬ 
ease, can be traced no farther back than the ninth or tenth cen¬ 
tury, while the contagious pleuro-pneumonia of bovinesonly dates 
from the middle of the eighteenth century; at least, we have no 
satisfactory proof to the contrary. Certain exanthematous affec¬ 
tions of cattle are also quite modern, and the so-called typhoid 
diseases of the equine species have been observed only for a com¬ 
paratively brief period; and so with other maladies of the domes¬ 
ticated animals. 
It must not be overlooked that the facilities for averting fam- 
ine and promoting intercourse which commerce and speedy com¬ 
munication have brought about, are not without their pains and 
penalties, in exposing countries and states to the introduction of 
maladies which are foreign to them and which are frequently all 
the more serious and deadly the farther they travel from their 
home ; for there are diseases of the pestilential kind peculiar to 
different countries, where they are maintained or generated, and 
which only appear in other regions as imported or exotic mal¬ 
adies. These belong more particularly to the contagious class, 
and they may be carried to countries widely separated from their 
own, owing to the vitality of the contagium, and become fixed in 
these, to the great destruction of the animals affected by them. 
Trade and intercourse are necessary for the welfare of the 
human family, and man cannot exist without the assistance of 
certain animals, whose multiplication and improvement constitute 
an essential feature of civilization. 
