AUTOBIOGRAPHICAL SKETCH. 153 



tance between the man who, like Oken, at- 

 tempts to construct the whole system of na- 

 ture from general premises and the one who, 

 while subordinating his conceptions to the 

 facts, is yet capable of generalizing the facts, 

 of recognizing their most comprehensive rela- 

 tions. No thoughtful naturalist can silence 

 the suggestions, continually arising in the 

 course of his investigations, respecting the 

 origin and deeper connection of all living be- 

 ings ; but he is the truest student of nature 

 who, while seeking the solution of these great 

 problems, admits that the only true scientific 

 system must be one in which the thought, the 

 intellectual structure, rises out of and is based 

 upon facts. The great merit of the physio- 

 philosophers consisted in their suggestiveness. 

 They did much in freeing our age from the 

 low estimation of natural history as a science 

 which prevailed in the last century. They 

 stimulated a spirit of independence among 

 observers ; but they also instilled a spirit of 

 daring, which, from its extravagance, has been 

 fatal to the whole school. He is lost, as an 

 observer, who believes that he can, with im- 

 punity, affirm that for which he can adduce 

 no evidence. It was a curious intellectual 

 experience to listen day after day to the lee- 



