INHERITANCE OF PARENTAL MODIFICATIONS 75 



fact of biology. No greater assumption has ever been made 

 as the basis of any biological theory, and it is pure assump- 

 tion, for as yet we have no evidence of any such mechanism 

 connecting muscle or nerve or bone cells with the germ cells. 

 In the absence of evidence in favor of the inheritance of 

 parental modifications among highly organized forms, and in 

 the presence of the tremendous assumption upon which this 

 hypothesis rests, I think it unsafe to accept this principle 

 even as a working theory. We may get definite evidence 

 sometime that will lead us to a different conclusion. The 

 phenomena of biology are wonderful, and even this great 

 assumption may yet be proven. It has not yet been proven 

 or been shown to be probable. 



Let us direct our attention to two further points in con- 

 nection with this part of the discussion. Many of the most 

 remarkable phenomena of nature we are sure have been 

 developed without the aid of the inheritance of parental 

 modifications, so we do not need the help of this hypothesis 

 because natural phenomena are "too wonderful to be ex- 

 plained without it." The color of flowers is useful to attract 

 insects. It has served its purpose when an insect has seen 

 the color and has responded. The plant lies passive ; the 

 insect actively responds. How can the reactionary effect of 

 the active response in the insect be inherited by the offspring 

 of the plant ? Or another equally absurd case : Many 

 animals, rabbits for example, are protectively colored. This 

 protective color serves its purpose, i.e. is used, when the fox 

 fails to see the rabbit. How can the failure of the fox to see 

 the rabbit produce such an effect on the germ cells of the 

 rabbit that the offspring of the rabbit shall be still more pro- 

 tectively colored ? Again : many seeds have spines or hooks 



