212 The h'ish Natujalist. November, 



light position, and will again assume the nocturnal position 

 as evening comes on. Here we see the leaves rising and 

 falline in the absence of the accustomed stimulation : this 

 change of position . . must be the result of the internal 

 conditions which habituall}' accompan}- the movement. This 

 is the characteristic par excellence of habit. It is consistent 

 with the doctrine of continuitj^ that in all living things there 

 is something psj'chic, and if we accept this point of view we 

 mnst believe that in plants there exists a faint copy of what 

 we know as consciousness in ourselves. 



" We have been considering the mnemic quality of move- 

 ments. The development of the individual takes place b}^ a 

 series of stages, each stage apparentlj^ serving as a stimulus 

 to the next . . like the movements linked together in a 

 habitual action. The rhythm of ontogen}^ is actuall}^ and 

 literally a habit. . . . There is a resemblance between the 

 two rhythms of development and memor}^ and there is at 

 least a prima facie case for believing them, to be essentially 

 similar. My view is the same as that of Hering, which is 

 generall}' described as the identification of menior}- and in- 

 heritance. . . . Evolution depends on a change in the 

 ontogenetic rhythm ; we have to ask in what waj\s the rhythm 

 can be altered. If ontogeny is a routine, each generation 

 must be mnemically connected with the next. This can onl}' 

 be possible if the germ cells are, as it were, in telegraphic 

 communication with the whole body of the organism. . . . 

 The mnemic theory of development depends on the possibi- 

 lity of somatic inheritance or the inheritance of acquired 

 characters. . . It is clear that there must be war to the 

 knife between the theory of Weismann and that of the 

 somatists. . . The strength of Weismann's theory lies in 

 its explanation of heredit3\ . . [but] I am not satisfied 

 with Weismann's theory. . . I incline to deny the distinc- 

 tion between germ and soma, to insist on the plain facts that 

 the soma is continuous with the germ cell and that the 

 somatic cells may have the same reproductive qualities as the 

 germ cells (as is proved by the facts of regeneration.) . . 

 The mnemic theory . . is strong precisely where Weis- 

 mann's views are weakest — namely, in giving a coherent 

 theory of the rhythm of development. We know that by 



