xxxvi Journal of Comparative Neurology. 



sensibility, notably the fingers ; that certain marked types of action, 

 such as imitation, arise first in connection with the hand ; that the 

 central organic preparation for volition is secured first in the arrange- 

 ments for hand movements ; all these facts indicate that the hand 

 movements are the best index of general and special sensibility in the 

 infant." Irrespective of any theory of the origin of volition, the au- 

 thor holds that for a long period the sensations which are stimuli to 

 movement become " effort stimuli" — the thing is a thing of sensation- 

 al dynamogeny or suggestion. 



Incidentally, in stating a formula for the dynamic influence of 

 stimuli, we are cautioned very truly that most appeals to mathematics 

 are an artificial show of exactness — a proposition for which readers of 

 modern German psychology may well be grateful. 



The theory of dynamogeny is illustrated in the fields of colour 

 vision and the origin of writing, after which the author proceeds at 

 once to the development of his genetic theory. For this purpose it is 

 of fundamental importance to define suggestion, which is for him 

 " the removal of inhibitions to movement by a certain condition of 

 consciousness." 



The following definitions will indicate the position taken : 



1. Physiological suggestion is the tendency of a reflex or sec- 

 ondary automatic process to get itself associated with and influenced 

 by stimulating processes of a physiological and vaguely sensory sort. 



2. Sensorimotor and ideo motor suggestion is the tendency of all 

 nervous reactions to adapt themselves to new stimulations, both sen- 

 sory and ideal, in such a way as to be more ready for the repetition or 

 continuance of these stimulations. 



3. Deliberative suggestion is the tendency of different competing 

 sensory processes to merge in a single conscious state with a single 

 motor reaction, illustrating the principle of nervous summation and 

 arrests. 



4. Imitative suggestion is the tendency of a sensory or ideal pro- 

 cess to maintain itself by such an adaptation of its discharges that 

 they reinstate in turn new stimulations of the same kind. 



Habit and accommodation thus become the two important facts 

 of the nascent psychical life, one providing for the repetition of what 

 is worth repeating the other for the adaptation of the organism to new 

 conditions. The fundamental question is then, " where and how 

 does the remarkable power of selection arise." Granting the law of 

 dynamogenesis, the author answers : " the life-history of organisms in- 

 volves from the start the presence of the organic analogue of the he- 



