114 ZOOLOGICAL PHILOSOPHY 



we should not have big draught- horses so heavy and so different from 

 the former, for none such are produced in nature ; in the same way 

 we should not have basset-hounds with crooked legs, nor grey-hounds 

 so fleet of foot, nor water-spaniels, etc. ; we should not have fowls with- 

 out tails, fantail pigeons, etc. ; finally, we should be able to cultivate 

 wild plants as long as we liked in the rich and fertile soil of our gardens, 

 without the fear of seeing them change under long cultivation. 



A feeling of the truth in this respect has long existed ; since the 

 following maxim has passed into a proverb and is known by all. 

 Habits form a second nature. 



Assuredly if the habits and nature of each animal could never vary, 

 the proverb would have been false and would not have come into 

 existence, nor been preserved in the event of any one suggesting it. 



If we seriously reflect upon all that I have just set forth, it will be 

 seen that I was entirely justified when in my work entitled Recherches 

 sur les corps vivants (p. 50), I estabhshed the following proposition : 



"It is not the organs, that is to say, the nature and shape of the 

 parts of an animal's body, that have given rise to its special habits 

 and faculties ; but it is, on the contrary, its habits, mode of life and 

 environment that have in course of time controlled the shape of its body, 

 the number and state of its organs and, lastly, the faculties which it 

 possesses." 



If this proposition is carefully weighed and compared with all the 

 observations that nature and circumstances are incessantly throwing 

 in our way, we shall see that its importance and accuracy are sub- 

 stantiated in the highest degree. 



Time and a favourable environment are as I have already said 

 nature's two chief methods of bringing all her productions into exist- 

 ence : for her, time has no limits and can be drawn upon to any 

 extent. 



As to the various factors which she has required and still constantly 

 uses for introducing variations in everything that she produces, they 

 may be described as practically inexhaustible. 



The principal factors consist in the influence of cUmate, of the vary- 

 ing temperatures of the atmosphere and the whole environment, 

 of the variety of localities and their situation, of habits, the com- 

 monest movements, the most frequent activities, and, lastly, of the 

 means of self-preservation, the mode of life and the methods of 

 defence and multiplication. 



Now as a result of these various influences, the faculties become 

 extended and strengthened by use, and diversified by new habits 

 that are long kept up. The conformation, consistency and, in short, 

 the character and state of the parts, as well as of the organs, are 



