142 CLUES AND SUGGESTIONS CHAP. 



that determines that the organism shall 

 live, and shall not rather die? The 

 needed development will not appear of 

 its own accord. The needed perception 

 of its necessity must exist somewhere ; 

 and the needed power of meeting that 

 necessity must exist somewhere also. 

 Moreover, the two must act in concert. 

 Those, therefore, who talk about that 

 combined perception and power existing 

 in Nature are using words with no 

 meaning, unless by Nature they mean a 

 conceiving and a perceiving agency. It 

 is on this principle alone that we can 

 explain very clearly why certain lines of 

 structure and certain special apparatuses 

 are common to all living things. The 

 assimilation of food, the support of 

 weight, some fulcrum for the attach- 

 ment of muscle, some circulatory fluid, 

 some vessels for the circulating fluids to 

 find a channel, some apparatus for the 



