314 STUDIES, SCIENTIf IC AND SOCIAL chap, xv 



latter " extrinsic " varieties, terms corresponding to 

 Weismann's " germ variation " and " somatic variation," 

 and these can in many cases only be distinguished from 

 each other by the test of cultivation under different con- 

 ditions. On this point Mr. Beeby remarks : — " The most 

 transient states of plants due to the direct action of their 

 environment are often far more distinct in appearance 

 from their normal forms than are some varieties from their 

 types ; but the first-named return at once to their normal 

 state on being removed from their special surroundings, 

 while the latter remain permanently distinct from their 

 types even when grown under circumstances most dis- 

 advantageous to the continuation of the particular varia- 

 tion. That these two kinds of variation exist in plants 

 is certain ; and the separation of them seems to be the 

 very basis on which all investigations of the Phanerogamia 

 must be made, if it is hoped that this branch of botany is 

 to throw any further light on " Evolution." ^ 



In conclusion, I submit that the whole body of facts in 

 relation to the direct action of the environment indicates 

 that modifications thus produced in the individual are not 

 transmitted to the offspring ; and that until it is demon- 

 strated by experiment that they are so transmitted, theories 

 of plant modification founded on that assumption are 

 altogether worthless. 



1 "On the Flora of Shetland." Annals of Scottish Natural History, 

 January, 1892, p. 52. 



