SUMMARY OF'PHILOSOPHIE ZOOLOGIQUE: 279 



I should again warn the reader to be on his guard 

 against the opinion that any animals can be said to live 

 if they have no " inward motion " of their own which 

 prompts them to act. We cannot call anything alive 

 which moves only as wind and water may make it 

 move, but without any impulse from within to execute 

 the smallest action and without any capacity of feeling. 

 Such a creature does not look sufficiently like the 

 other things which we call alive; it should be first 

 shown to us, so that we may make up our minds 

 whether the facts concerning it have been truly stated, 

 and if so, what it most resembles ; we may then classify 

 it accordingly. 



" Some animals change their place by creeping, some 

 by walking, some by running or leaping ; others again 

 fly, while others live in the water and swim. 



" The origin of these different kinds of locomotion is 

 to be found in the two great wants of animal life : 1, the 

 means of procuring food ; 2, the search after mates with 

 a view to reproduction. 



" Since then the power of locomotion was a matter 

 affecting their individual self-preservation, as well as 

 that of their race, the existence of the want led to the 

 means of its being gratified." * 



Lamarck is practically at one with Dr. Erasmus 

 Darwin, that modification will commonly travel along 

 three main lines which spring from the need of re- 

 production, of procuring food, and (Dr. Darwin has 

 added) the power of self-protection ; but Dr. Darwin's 

 treatment of this part of his subject is more lucid and 

 * Phil. Zool.,' torn. i. p. 98. 



