Literary Notices. xciii 



"Whether these actions be purely unconscious and automatic or more 

 or less intelligent and conscious does not alter the fact that they are 

 necessarily inherited. The habits and qualities that have been acquired 

 by the individuals of each generation' could have become fixed in no 

 other way than through heredity. Many of these acts, which older nat- 

 uralists explained by that evasive word "instinctive," may be the 

 mere unconscious outcome of organization, comparable to vegetative 

 growth; but insects exhibit all degrees of intelligence in their habits and 

 actions, and they perform acts which, however voluntary and, as I be- 

 lieve, conscious in many cases, as that of our Yucca Moth, could not be 

 performed were the tendency not inherited. Every larva which spins or 

 constructs a hibernaculum, or a cocoon in which to undergo its transfor- 

 mations, exemplifies the power of heredity in transmitting acquired pe- 

 culiarities. A hundred species of parasitic larvae, e. g., of the family 

 Braconida:, which in themselves are almost or quite indistinguishable 

 from one another structurally, will nevertheless construct a hundred dis- 

 tinctive cocoons — differing in form, in texture, in color, and in marking 

 — each characteristic of its own species and in many instances showing 

 remarkable architectural structures, and can have little or nothing to do 

 with the mere organization or form or structure of the larva, but they 

 illustrate in the most convincing manner the fact that the tendency to 

 construct and the power to construct the cocoon after some definite plan 

 must be fixed by heredity, since there is no other way of accounting for 

 it. This fact alone, which no one seems to have thought of in the dis- 

 cussion, should be sufficient to confound the advocates of the non-trans- 

 missibility of acquired characteristics." 



"Thus to my view modification has gone on in the past, as it is going 

 on at the present time, primarily through heredity in the insect world. 

 I recognize the physical influence of environment; I recognize the effect 

 of the interrelation of organisms; I recognize, even to a degree that few 

 others do, the psychic influence, especially in higher organisms — the 

 power of mind, will, effort, or the action of the individual as contradis- 

 tinguished from the action of the environment ; I recognize the influence 

 of natural selection, properly limited; but above all, as making effective 

 and as fixing and accumulating the various modifications due to these or 

 whatever other influences, I recognize the power of heredity, without 

 which only the first of the influences mentioned can be permanently op- 

 erative." 



