236 1.AMARCK, HIS LIFE AND WORK 



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^and modern form the essential principles of evolution, 

 amarck insists that ti^jnewithsiiMimit and favorabl e 

 /conditions are the two principal means or factors in 

 I the production of plants and animals. ' Under the 

 1 head of favorable conditions he enumerates variations 

 in climate, temperature, the action of the environ- 

 ment, the diversity of local causes, change of habits, 

 movement, action, variation in means of living, of 

 preservation of life, of means of defence, and varying 

 modes of reproduction. As the result of the action 

 of these different factors, the faculties of animals, 

 developed and strengthened by use, become diversi- 

 fied by the new habits, so that by slow degrees the 

 new structures and organs thus arising become pre- 

 served and transmitted by heredity." 

 * In this address it should be noticed that nothing is 

 said of willin_g^and of internal feeling, which have been 

 so rnuchjTnsumiderstoo3~ana~rid^^^^ or of the direct 



or indirect action of the environment. He does 

 speak of the bird as wishing to strike the water, but 

 this, liberally interpreted, is as much a physiological 

 impulse as a mental desire. No reference also is 

 made to geographical isolation, a factor which he 

 afterwards briefly mentioned. 



Although Lamarck does not mention the principle 

 of selection, he refers in the following way to compe- 

 tition, or at least to the checks on the too rapid mul- 

 tiplication of the lower invertebrates : 



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" So were it not for the immense consuoJ^tion as 



food which is made in nature of animalg^hich com- 

 pose the lower orders of the animal Iji'iigdom, these 

 animals would soon overpower and perhaps destroy, 



