ON THE DIRECTIVITY OF LIFE. 



261 



differences are due to having been "dispersed, and having found 

 themselves in some different kind of surroundings " (p. 252, para- 

 graph 5). Even when the points in which they differ are greater 

 than those in which they resemble each other, we are asked to believe 

 these are due to the " response to the conditions of life," which is 

 really begging the question, for there is no evidence in the vast 

 majority of cases of any common origin, or that they had ever been 

 *' dispersed " to different surroundings. 



In 1909 the Cambridge Philosophical Society published a series 

 of essays in commemoration of the centenary of Charles Darwin's 

 birth, and of the fiftieth anniversary of the publication of The 

 Origin of Species. One of these essays is by Georg Klebs, Ph.D., 

 Professor of Botany in the University of Heidelberg, and is entitled 

 "Influence of Environment on Plants." Speaking of modifications 

 induced by experiments under changes of environment he says : — 

 " So far as the experiments justify a conclusion, it would appear 

 that such alterations are not inherited by the offspring. Like all 

 other variations, they appear only so long as special conditions 

 prevail in the surroundings." 

 Again : — 



" Two methods of experimental research may be adopted, the 

 effect of crossing distinct species, and secondly the effect of definite 

 factors of the environments. . . . The " (second) " method of 

 producing constant races by the influence of special external con- 

 ditions has often been employed. . . . But as regards the main 

 question, whether constant races may be obtained by this means, the 

 experiments cannot yet supply a definite answer." 

 And again : — 



" During long cultivation, under conditions which vary in very 

 different degrees . . . it is possible that sudden and special 

 disturbance in the relations of the cell substances have a directive 

 influence on the inner organizations of the sexual cells, so that not 

 only inconstant, but also constant, varieties will be formed. Definite 

 proof in support of this view has not yet been furnished, and we must 

 admit that the question as to the cause of heredity " {i.e., heredity 

 which results in variation) "remains fundamentally as far from solution 

 as it was in Darwin's time." Professor W. Bateson, F.E.S., also in the 

 same volume deals with " Heredity and Variation in Modern Lights," 

 and says as follows : — " As Samuel Butler so truly said, ' To me it 



