Lamarcl^s Laws of Evolution 303 



In the matter of the origin of plant and animal forms, 

 Lamarck had been an orthodox fixist, following in the foot- 

 steps of Linnaeus. He found the latter's linear system of 

 classification quite inadequate. After extending it to the ut- 

 most limits of its possibilities he discovered the necessity of the 

 branching arrangement of classes and orders to indicate 

 natural groups. When he threw himself into the study of 

 invertebrates he brought order into the chaos of classifica- 

 tion, especially in the class " worms "; but in the course of 

 his studies he found himself gradually losing his grip on the 

 permanent " species " — and becoming a transformist. The 

 more he studied the more his conviction grew that the ex- 

 isting plants and animals were not only the descendants of 

 the plants and animals of the past, but that living forms had 

 in the course of time become transmtited into different form^s, 



Saint-Hilaire was sympathetic and encouraging, but not 

 very powerful. Cuvier was hostile and aggressive — and in- 

 fluential. When Lamarck brought his views into the open it 

 meant conflicts and bitterness. But he did not mince mat-, 

 ters. He knew that the conclusions to which his studies had 

 brought him meant first of all the heresy of transmutation- 

 ism: the living species were not the direct descendants of 

 identical forms originally created, but forms modified in the 

 course of the ages into very different beings. He knew, in 

 the second place, that his doctrine was to be applied gen- 

 erally. He said quite explicitly, " All species, including man, 

 are descended from other species." And he knew in the third 

 place that he was propounding an explanation of how trans- 

 formation of species had come about. 



Lamarck's Laws of Evolution 



In his Philosophie Lamarck summarized his principles 

 into two laws: 



" First Law: In every animal which has not exceeded the Hmit of its 

 development, a more frequent and continuous use of any organ gradually 



