THE LAMARCKIAN THEORY 



541 



The Lamarckian must, however, go farther than this to prove 

 his case, by showing that these effects upon individuals are inher- 

 ited by their offspring. The process of such evolutionary causa- 

 tion may be illustrated concretely by citing some of Lamarck's 

 own examples in modern terms. If swift-footed animals, like deer, 

 have acquired their fleetness by running from their enemies, it 

 follows that each generation has been forced to exert itself to the 

 utmost, like an athlete always 

 in training for a race, and 

 that the effects of this training 

 in each generation have been 

 passed on to the next. Thus, 

 fleetness has gradually in- 

 creased up to limits deter- 

 mined by the nature of the 

 organism. In Hke manner, 

 the fleetness of the pursuing 

 wolves may have been in- 

 creased generation after gen- 

 eration. If cunning were 

 practiced, the more effective 

 use of the brain would be 

 passed on to the descendants. 

 Animals living in caves cease 



to use their eyes, and the de- t- or^T t t, ^- j. j t i 



•, . riG. 297. — Jean Baptiste de Lamarck 



generation that follows is (i744_i829), first to propose a theory 

 supposed to be cumulatively of the causes of organic evolution that 

 inherited until blind species received serious consideration. 



are produced. Animals living (From Pirsson and Schuchert, "Textbook of 



in cold climates, where the Geology •■John wiiey& sons, copyright, 1924. 



' _ reprinted by permission.) 



environment stimulates a 



heavier growth of hair or the formation of more fat beneath 

 the skin, are believed to transmit these characters by heredity 

 and thus to reach the state seen in Arctic forms. An animal 

 like the giraffe (Fig. 298) is assumed to have developed its neck 

 by reaching up to browse upon the higher vegetation and to 

 have inherited the slightly greater length of neck acquired by 

 each generation. 



Objections to the Theory. — There would be no objection 

 to the Lamarckian Theory, if it could be shown that the effects 



