246 LAMARCK, HIS LIFE AND WORK 
kind. Finally, this change propagates itself and is 
then handed down (se passe) to all the individuals which 
succeed and which are submitted to the same circum- 
stances, without their having been obliged to acquire 
it by the means which have really created it. 
‘Besides, in the unions between the sexes the in- 
termixtures between individuals which have different 
qualities or forms are necessarily opposed to the con- 
stant propagation of these qualities and forms. We 
see that which in man, who is exposed to such different 
circumstances which influence individuals, prevents 
the qualities of accidental defects which they have 
happened to acquire from being preserved and propa- 
gated by heredity ( géxération). 
“You can now understand how, by such means and 
an inexhaustible diversity of circumstances, nature, 
with sufficient length of time, has been able to and 
should produce all these results. 
“Tf I should choose here to pass in review all the 
classes, orders, genera, and species of animals in exist- 
ence I could make you see that the structure of in- 
dividuals and their organs, faculties, etc., is solely the 
result of circumstances to which each species and 
all its races have been subjected by nature, and of 
habits that the individuals of this species have been 
obliged to contract. 
“The influences of localities and of temperatures 
are so striking that naturalists have not hesitated to 
recognize the effects on the structure, the develop- 
ments, and the faculties of the living bodies subject to 
them: 
“We have long known that the animals inhabiting 
the torrid zone are very different from those which 
live in the other zones. Buffon has remarked that 
even in latitudes almost the same the animals of the 
new continent are not the same as those of the old. 
“ Finally the Count Lacépéde, wishing to give to 
this well-founded fact the precision which he believed 
