170 DARWINISM AND HUMAN LIFE 



our survey if we quote a brief statement of the 

 idea as expounded by Lloyd Morgan (" Habit 

 and Instinct" (1896), p. 319) : 



" Persistent modification through many genera- 

 tions, though not transmitted to the germ, neverthe- 

 less affords the opportunity for germinal variation 

 of like nature. 



" Suppose that a group of plastic organisms is 

 placed under new conditions. Those whose innate 

 plasticity is equal to the occasion are modified 

 and survive. Those whose plasticity is not equal 

 to the occasion are eliminated. . . . Such modifica- 

 tion takes place generation after generation, but, 

 as such, is not inherited. . . . But any congenital 

 variations similar in direction to these modifications 

 will tend to support them and to favour the 

 organism in which they occur. Thus will arise 

 a congenital predisposition to the modifications 

 in question. 



" The plasticity still continuing, the modifica- 

 tions become yet further adaptive. Thus plastic 

 modification leads, and germinal variation follows ; 

 the one paves the way for the other. 



" The modification, as such, is not inherited, 

 but is the condition under which congenital 

 variations are favoured and given time to get a 

 hold on the organism, and are thus enabled by 

 degrees to reach the fully adaptive level." 



PRACTICAL IMPORT OF THE QUESTION AS TO THE 

 TRANSMISSIBILITY OF ACQUIRED CHARACTERS. 

 It is scarcely necessary to point out that the long- 

 drawn-out discussion is one of great importance, 

 affecting our whole theory of evolution, and even 

 our everyday conduct. Herbert Spencer went 

 the length of saying that " a right answer to the 



