Influence of circumstances on the Actions of Animals. 1065 
cumstances on the habits, and in that of habits on the forms, the dis- 
position,and the proportion of the parts of animals. A great numder of 
citations being unnecessary, the point of discussion reduces itself to 
this. The fact is, that diverse animals have each, according to their 
genus and their species, particular habits, and always an organiza- 
tion which is perfectly in harmony with those habits. From the 
consideration of this fact it seems*that one is at liberty to admit 
one or the other of the two following hypotheses, neither of which 
can be proved. 
Conclusions admitted at this time: (1) Nature (or its Author, 
in creating animals has foreseen all possible kinds of circumstances 
in which they may have to live, and has given to each species a 
permanent organization, as well as a pre-determined form invari- 
able in its parts; that it forces each species to live in the places 
and the climates where one finds them, and to preserve there the 
habits which it has. 2. My own conclusion: Nature in producing 
successively all species of animals, and commencing by the most 
imperfect or simple, to terminate its work by the most perfect, has 
gradually complicated their organization, and these animals, spread- 
ing themselves gradually into all habitable regions of the globe- 
each species has been subjected to the influence of the circumstances 
in which it is; and these have produced the habits which we 
observe and the modifications of its parts. 
The first of these two conclusions is that which has been held to 
the present time, that is to say, it supposes in each animal a per- 
manent organization and parts which have never varied and which 
will never vary; it supposes still thatthe circumstances of the places 
Which each species of animal inhabits never vary in these places) 
for if they should vary, the same animals would not be able to live 
there, and the possibility of recognizing such elsewhere, and of going 
or transporting themselves there, would be denied them. 
The second conclusion is mine. It supposes that, by the influence 
of circumstances on the habits and that which follows these habits 
on the organization, that each animal would receive in its parts and 
organization, modifications susceptible of becoming very consider 
able, and thus to have given origin to the state in which we find all 
animals, To prove that this second conclusion is without founda- 
Hon, it is necessary to first prove that no point of the surface of the 
