320. LAMARCK, HIS LIFE AND WORK 
always pair, they would reproduce the same features, 
and the successive generations being confined to such 
unions, a special Aine distinct race would then be 
formed. “TB perpetual unions between individuals 
which do not have the same peculiarities of form 
would cause all the characteristics acquired by special 
circumstances to disappear. 
“From this we can feel sure that if distances of 
habitation did not separate men the intermixture by 
generation would cause the general characteristics 
which distinguish the different ‘nations to disappear. 
“Tf I should choose to pass in review all the classes, 
all the orders, all the genera, and all the species of 
animals which exist, I should show that the structure 
of individuals and their parts, their organs, their 
faculties, etc., etc., are in all cases the sale result of 
the circumstances in which each species is found to 
be subjected by nature and by the habits which the 
individuals which compose it have been obliged to 
contract, and which are only the product of a power 
primitively existing, which has forced the animals into 
their well-known habits. 
“We know that the animal called the az, or the 
sloth (Bradypus tridactylus), is throughout life ina 
condition so very feeble that it is very slow and lim- 
ited in its movements, and that it walks on the ground 
with much difficulty. Its movements are so slow 
that it is thought that it cannot walk more than fifty 
steps ina day. It is also known that the structure 
of this animal is in direct relation with its feeble state 
or its inaptitude for walking; and that should it de- 
sire to make any other movements than those which 
it is seen to make, it could not do it. 
“ Therefore, supposing that this animal had received 
from nature its well-known organization, it is said that 
this organization has forced it to adopt the habits and 
the miserable condition it is in. 
“lam /far from thinking so because: Tam con- 
