HISTORY AND THEORIES OF EVOLUTION 387 



seek general principles, and these must always accord with 

 facts" — had been remembered and applied by him and his 

 successors, science need not have progressed so slowly for so 

 many centuries. 



The special creation theory interrupted scientific thought 

 and investigation for many centuries. Philosophy preceded 

 science in the line of evolutionary thought. Leibnitz, a German 

 philosopher (1646-1716), believed that "living beings form an 

 unbroken series from the simple to the complex, some steps in 

 the series having become extinct."^ Buffon (1707-88) thought 

 that organisms could be modified by changes in food and envi- 

 ronment or by domestication, and that parts could be modified 

 by disuse. He was one of the first to attempt an explanation 

 of the geographic distribution of animals. 



Erasmus Darwin (1781-1802), grandfather of Charles 

 Darwin, author of "The Origin of Species," was a physician and 

 physiologist as well as a gardener and lover of plants. He 

 thought that the various plants and animals were descended 

 from "few ancestral forms or possibly from one and the same 

 kind of vital filaments." He emphasized function, saying that 

 "from their first rudiment or primordium to the termination 

 of their lives all animals undergo perpetual transformations; 

 which are in part produced by their own exertions in conse- 

 quence of their desires and aversions, of their pleasures and their 

 pains, or of irritations or of associations; and many of these 

 acquired forms or propensities are transmitted to their poster- 

 ity." 



Lamarck (1744-1829), although unappreciated in his own 

 day, scientists of the present day, whether agreeing with him or 

 not, admit to be one of the bravest of pioneers. Haeckel 

 says "to Lamarck will remain the immortal glory of having for 

 the first time established the theory of descent as an independ- 

 ent, scientific generalization of the first order as the foundation 

 of the whole of biology." To quote Lamarck, "Nature in all 

 her work proceeds gradually and could not produce all animals 

 at once. At first she formed only the simplest, and passed 

 from these on to the most complex." He gives four laws as 

 the summing up of his ideas: 



1 McFarland's " Biology." 



