M. Roulin, in a paper read before the French 
academy of Sciences in 1828, on the changes 
which the domestic animals of Europe undergo 
when transported to the equatorial regions of the 
New world, states that the mammiferous animals 
brought from the Old to the New continent, are 
pigs, sheep, goats, asses, horses, cows, and dogs, 
all of which are become more numerous than the 
indigenous animals of the new countries. It ap- 
| pears that the hog, in the warm valleys of South 
America, wandering in the woods, and subsisting 
upon wild fruits, becomes very ferocious, and as- 
sumes almost the character of the wild boar. 
The principal treatment to insure fecundity in 
| these animals, was to pasture them in situations 
| where the food possessed saline properties. In 
| places where the quantity of salt, either in the 
|| water or plants, was small, they were found to 
|| deteriorate in quality, and to diminish in num- 
| ber. In these climates, the cow undergoes a 
material change. It no longer furnishes the con- 
| stant supply of milk which we obtain from it by 
| artificial means in Europe; and, in order to ob- 
| tain that fluid at all, it is necessary that the calf 
| should be continually with its mother. The milk 
| obtained for domestic use, is only that which ac- 
| cumulates during the night when the calf is in a 
| quiescent state; when the calf ceases to suck, the 
milk immediately dries up. The bulls and cows 
| introduced from Europe into South America soon 
become wild; and, at the present time, it is only 
| by repeated battues that they are kept in sub- 
| jection. The ass undergoes, in the provinces 
| which M. Roulin has visited, less change than 
any other animal. He never becomes wild but 
in situations where the labour is excessive. The 
| sheep introduced into America were not the 
| merinos, but the two species called tana basta and 
| burda, In temperate climates, they have multi- 
plied abundantly, without showing any tendency 
to submit to the domination of man. In the 
burning climate of the plains, they do not pro- 
|| pagate freely ; and a curious phenomenon is there 
witnessed. The wool of the lambs grows at first, 
"as in more temperate climates, but rather slowly. 
When in a fit state for shearing, there is nothing 
remarkable about its quality ; and, when removed, 
it grows again as in temperate climates: but if 
the proper time for shearing is allowed to go by, 
the wool becomes thick, falls off in patches, and 
leaves underneath, not a new growth of wool or 
|| a barren place, as if from disease, but a short 
|| shining and close hair, exactly like the hair of 
the goat, in the same climate: and, where this 
hair once appears, there is never any return of 
wool. The goat, notwithstanding its form, which 
appears adapted to mountainous situations, 
thrives much better in the low valleys of South 
America than on the high points of the Cordil- 
leras, It undergoes a lactiferous change similar 
|| to that of the cow. The conclusions drawn from 
the report are, 1st, That every animal, like man, 
ae time to accustom itself to climate; and, 
i 
ACCLIMATATION OF ANIMALS. 
27 
2d, that domestic animals, when left to them- 
selves, have a great tendency towards the organi- 
zation of those of the same species in a wild state ; 
and that a very short time only is necessary to 
produce that transformation. 
That degeneration of individuals, so frequently 
remarked in animals and plants, results inevita- 
bly from their being imperfectly acclimated ; and 
many of the diseases with which they are afflicted 
proceed from a similar cause. In the southern 
countries of Hurope, the insensible exhalations 
which transpire from the surface of the skin are 
usually considerable, while the contrary takes 
place in its more northern regions. Hence, in 
importing animals from the South to the North, 
due care should be taken to overcome their con- 
stitutional habit ina gradual manner. There is 
a constant determination of all useless or hurtful 
matters towards the skin in warm climates; 
while, in cold countries, transpiration is counter- 
acted, arrested, or suspended, and always modi- 
fied in a greater or less degree. Hence, unless 
their change of situation is cautiously effected, 
animals become predisposed to several cutaneous 
disorders, to obstructions, enlargement of the 
liver, and other maladies of this nature. Again, 
when animals are suddenly transported from the 
North to the South, and without the necessary 
precautions, the consequences are not less danger- 
ous than those already enumerated; as the ex- 
cretory functions of the skin are less energetic in 
cold than in warm countries, the internal func- 
tions possess a greater relative energy; and, on 
removing them to the South, their constitutional 
habit becomes modified. The insensible tran- 
spiration of the skin necessarily becomes greater, 
and the active forces of the system tend towards 
the surface,—a change which may occasion many 
dangerous maladies, such as putrid fevers. The | 
only effectual way of counteracting these serious 
inconveniences, is by adopting a system proper to 
all the circumstances of the locality, according to | 
the principles laid down in our best treatises. 
Climate exercises an important influence over | 
many of those characteristics which commonly | 
serve to distinguish one species from another; 
and it is highly probable, that many animals, 
which are commonly considered by naturalists as 
belonging to allied species, may in reality be no- 
thing more than permanent races, descended from 
the same original stock, and preserved distinct sole- 
ly by the influence of climate. The usual charac- 
ters of animals, when long exposed to dry and 
warm climates, may be stated in general terms to 
be the following :—Their skin is thin, supple, and 
oily ; their hair scanty and fine; their limbs long; | 
the tendinous parts distinct; their horns hard, | 
dry, and brittle; the hoof contracted; the feet 
harrow and sound; the muscles dry and but | 
slightly fat; and their temperament rather san- 
guineous than lymphatic. The circulation of the 
blood becomes accelerated; they possess much | 
ardour, energy, and courage; while the several 
— 
a 
