428 BIOLOGY AND ITS MAKERS 



evolution, was unable to state explicitly what these causes 



were." 



Darwin and Wallace. — In 1858 we come to the crown- 

 ing event in the rise of evolutionary thought, when Alfred 

 Russel Wallace sent a communication to Mr. Darwin, beg- 

 ging him to look it over and give him his opinion of it. ' Darwin, 

 who had been working upon his theory for more than twenty 

 years, patiently gathering facts and testing the same by 

 experiment, was greatly surprised to find that Mr. Wallace 

 had independently hit upon the same principle of explaining 

 the formation of species. In his generosity, he was at first 

 disposed to withdraw from the field and publish the essay of 

 Wallace without saying anything about his own work. He 

 decided, however, to abide by the decision of two of his 

 friends, to whom he had submitted the matter, and the result 

 was that the paper of Wallace, accompanied by earlier com- 

 munications of Darwin, were laid before the Linnaean Society 

 of London. This was such an important event in the his- 

 tory of science that its consideration is extended by quoting 

 the following letter: 



"London, June 30th, 1858. 



"My Dear Sir: The accompanying papers, which we 

 have the honor of communicating to the Linnaean Society, 

 and which all relate to the same subject; viz., the laws which 

 affect the production of varieties, races, and species, contain 

 the results of the investigations of two indefatigable natural- 

 ists, Mr. Charles Darwin and Mr. Alfred Wallace. 



"These gentlemen having, independently and unknown 

 to one another, conceived the same very ingenious theory to 

 account for the appearance and perpetuation of varieties 

 and of specific forms on our planet, may both fairly claim the 

 merit of being original thinkers in this important line of 

 inquiry; but neither of them having published his views, 



