8 THE THEORY OF EVOLUTION 







time of Darwin, is that 'there are as many species 

 as God created in the beginning." Lamarck, who 

 had accomplished an immense amount of systematic 

 work in zoology and botany, felt compelled to deny 

 the Linnsean doctrine and to take up the alternative 

 explanation of evolutionary descent. 



Lamarck's best known work is his "Philosophic 

 Zoologique," which is very abstruse and speculative 

 and contains but little evidence for his conclusions, 

 other than a reference to his wide experience as a 

 systematist, i. e., a student of classification. He 

 maintained that the species was an artificial con- 

 ception and that nature knew only individuals in 

 graduated steps of relationship. Most of the book 

 is devoted to a consideration of the causes which 

 have led to the transformation of animals and the 

 conclusion is that adaptation to environment is the 

 most efficient factor. This adaptation is to be ex- 

 plained by the fact that the conditions of life deter- 

 mine the manner in which animals make use of their 

 organs; these are developed and perfected by use, 

 but dwindle and are atrophied through disuse. An- 

 imals which live in the dark, as in caves or in the 

 abysses of the ocean, are blind, while their organs 

 of feeling are highly developed to take the place of 

 sight. As the environment is subject to constant 

 change, adaptation requires that living beings should 

 be correspondingly, though gradually, transformed. 



Modern accounts of Lamarck's views are almost 

 always taken from the "Zoological Philosophy," but, 



