VIII DARWINISM AND HOLISM 201 



mixture of parental elements and are thus potent sources 

 of Variation. But Variation operates even apart from and 

 in the absence of sexual reproduction and the related meiotic 

 divisions of the germ-cells. And the question remains 

 whether the individual life is, in fact, so isolated from the 

 germ-cell that it has no influence on the latter and the 

 resulting offspring. On this isolation Weismann was par- 

 ticularly insistent, and in the popular mind his teaching is 

 identified with the doctrine that acquired characters are 

 not transmissible. The principle of the non-transmissibility 

 of organic modifications (as above defined) rests on empiri- 

 cal experience, as no clear and indisputable case of the pass- 

 ing of such individual modifications to the offspring has been 

 recorded or observed. Weismann's germ-cell theory was 

 intended to supply the scientific basis for this negative re- 

 sult; but in the end he so completely isolated the germ- 

 cell from the rest of the individual organism that he came 

 to consider it practically impossible that modifications 

 could become hereditary, or that somatic cells could 

 in any way, except through nourishment, influence the 

 germ-cells. 



There can be little doubt that in adopting this extreme 

 standpoint Weismann went too far. He riot only cut clean 

 away from the Darwinian tradition, but also, in fact, made 

 it impossible to understand the double fact of progress and 

 adaptation; in other words, to understand how the experi- 

 ence of the race, which after all is only accumulated indi- 

 vidual experience, helps to promote development, and to 

 mould it in congruity with the environment. Unless the 

 "trial and error" experiments of individuals produce some 

 racial result; if, in other words, every individual throughout 

 the ages has to begin to learn once more at the beginning, 

 org^ic progress becomes unintelligible, if not impossible. 

 The extreme isolation and independence which Weismann 

 attributed to the germ-cell therefore led to a further hypoth- 

 esis intended to give the individual some sort of indirect 

 influence in shaping racial evolution. He assumed that a 

 struggle for existence took place among the elements or 



