NATURAL SELECTION 151 



the volvox, judged by one important test its possession of 

 chlorophyll and its diet is a vegetable. Didinium, a hunter 

 Infusorian that throws trichocysts (little javelins), distinguishes 

 two nearly allied Infusorians, Paramoecium aurelia and Para- 

 moecium bursaria, from one another, attacks the former and 

 avoids the latter. 1 Even bacteria have their wits about them ; a 

 drop of poisonous acid causes a sauve-qui-peut, and, as everyone 

 knows, they know whom and what to attack. 



Can such acts be entirely unaccompanied by consciousness ? 

 It seems to me unlikely. Consciousness, as we know, may be 

 complete or incomplete. While writing I have been dimly 

 conscious of a lamp, a ticking clock, a fire sleepily burning, and 

 so forth. My conscious thoughts have been focussed upon the 

 micro-organisms and their " psychic" life, if with M. Binet we 

 may so dignify it. Is it not possible that they may have some- 

 thing similar to what we call sub-consciousness in ourselves ? 

 In thinking of these matters it has sometimes occurred to me as 

 a difficulty that our lower nerve centres are far higher in the 

 scale than these protozoa which have no cells at all set apart as 

 nerves. These lower centres must, I believe, have a dim con- 

 sciousness of their own. If the disarrangement of the bed- 

 clothes allows a cold draught to penetrate to us when asleep, we 

 sometimes withdraw a foot or a hand without waking. But can 

 we be sure that there is no consciousness in some lower part of 

 the brain or in some nerve ganglion which orders the movement ? 

 If so, it is not we who are conscious but a subordinate official in 

 our service. 



We decide, then, that where life is there is mind and there is 

 consciousness. Let them be as rudimentary as it is possible to 

 be without being non-existent. They must be there since the 

 other alternative, that they have been implanted at a compara- 

 tively late stage of development, is inadmissible. 



The expression " the all-sufficiency of Natural Selection" was "The all- 

 first used, I believe, by Weismann, and, though true in my *" ^atuS 

 opinion in the sense in which it was used, is undoubtedly liable Selection " 

 to misinterpretation. It was meant to express his view that the 



1 Loc . cit. 



