104 THE SURVIVAL OF THE UNLIKE. [ill. 



acquired characters must be transmitted!* The only 

 escape from this position is an arbitrary assumption that 

 one plasm is impressionable and that the other is not; 

 and, now that we can no longer relegate the germ -plasm 

 to imaginary deep-seated germ -cells, such an assnmp- 

 tion is too bold, I think, to be suggested. 



The entire Weismannian hypothesis is built upon the 

 assumption that all permanent or progressive variation 

 is the result of sexual union; but I have shown that 

 there is much progressive variation in the vegetable 

 kingdom which is purely asexual or vegetative, and, for 

 all we know, this type of modification may proceed in- 

 definitely. There is no doubt of the facts; and the only 

 answer to them which I can conceive the Weismannian 

 to make is that these progressive variations arise because 

 of the latent influence of ancestral sexual unions. In 

 reply to this, I should ask for proofs. Hosts of fungi 

 have no sex. I am not convinced but that there may be 

 strains or types of some species of filamentous algOB and 

 other plants in which there has never been sexual union, 

 even from the beginning. And I should bring in re- 

 buttal, also, the result of direct observation and experi- 

 ment to show that given hereditable asexual variations are 

 often the direct result of climate, soil or other impinging 

 conditions. As a matter of fact, we know that acquired 

 characters may be hereditary in plants; if the facts do 

 not agree with the hypothesis, so much the worse for 

 the hypothesis. Unfortunately, the hypothesis is too 



* Essentially this position is expressed in Cope's theory of Diplogenesis, which 

 insists that " the effects of use and disuse "' f and, I suppose, of other stimuli] "are 

 two-fold; viz., the effect on tlie soma, and the effect on the germ-plasma." Tlie 

 character which appears in the soma " must be potentially acquired by the germ- 

 plasma as well as actually by the soma." See Cope, "Primary Factors of Organic 

 Evolution," 1896, pp. 441 to 444. 



