CHAPTER XV 



WHEN DID LAMARCK CHANGE HIS VIEWS REGARD- 

 ING THE MUTABILITY OF SPECIES? 



Lamarck's mind was essentially philosophical. 

 He was given to inquiring into the causes and origin 

 of things. When thirty-two years old he wrote his 

 " Researches on the Causes of the Principal Physical 

 Facts," though this work did not appear from the 

 press until 1794, when he was fifty years of age. In 

 this treatise he inquires into the origin of compounds 

 and of minerals ; also he conceived that all the rocks 

 as well as all chemical compounds and minerals orig- 

 inated from organic life. These inquiries were re- 

 iterated in his " Memoirs on Physics and Natural 

 History," which appeared in 1797, when he was fifty- 

 three years old. 



The atmosphere of philosophic France, as well as 

 of England and Germany in the eighteenth century, 

 was charged with inquiries into the origin of things 

 material, though more especially of things immaterial. 

 It was a period of energetic thinking. Whether 

 Lamarck had read the works of these philosophers 

 or not we have no means of knowing. Buflon, we 

 know, was influenced by Leibnitz. 



Did Buffon's guarded suggestions have no influence 

 on the young Lamarck ? He enjoyed his friendship 



