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1066 Influence of circumstances on the Actions of Animals. 
surface of the globe has ever varied its nature, its exposure, its 
elevation, its climate, etc., etc.; and to prove farther that no part of 
an animal undergoes, after a length of time, any modifications due 
to change of circumstances and from the necessity which constrains 
them to a kind of life and of action different from that which has 
been habitual with them. 
Now, if only one fact proves that an animal, after a long time of 
domestication, differs from the wild species from which it came, and 
if among the domesticated species there is found a great difference 
of conformation among individuals who have been subjected to a 
given habit, and those who have been constrained to adopt a differ- 
ent habit, then it will be certain that the first conclusion does not 
conform to the laws of nature and that, on the contrary, the second 
is perfectly in accord with them. All agree then to prove my as- 
sertion: that it is neither the form of the body nor of its parts 
which gives origin to the habits and the manner of life of the ani- 
mals; but it is, on the contrary, the habits, the manner of life and 
all the other influential circumstances, which have, with time, con- 
structed the form of the body and of the parts of the animals. With 
“new forms new faculties have been acquired, and little by little 
‘Nature has come to form animals, such as we actually see them. 
Can there be in Natural history a more important consideration 
and to which one should give more attention than that which I ex- 
pound? 
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