112 BIOLOGICAL LECTURES. 



by the higher, — the general trend of the answer is, I think, 

 evident. I should be inclined to interpret the facts presented 

 somewhat as follows : The claim that the motor processes of 

 unicellular organisms form a connecting link between inorganic 

 processes and the vital phenomena of higher creatures clearly 

 receives no justification for the organisms studied. Every 

 influence coming in from outside passes, as it were, through a 

 sort of central station, where it is completely transformed to 

 appear as a reflex action, the nature of which is conditioned by 

 the form and structure of the organism ; and the steps in the 

 transformation are no more evident than they are in the higher 

 forms. The reactions of these creatures are indeed simple, but 

 not qualitatively of a different sort from those of higher organ- 

 isms, so that for motor reactions of the sort studied I do not 

 see that a knowledge of the conduct of these particular uni- 

 cellular organisms really adds to our insight into the causal 

 relations in the activities of higher animals. 



On the other hand, if we dismiss any idea of getting from 

 them knowledge of a different kind from that gained by the 

 study of other groups, then the behavior of these Protozoa is 

 of the greatest interest from the standpoint of comparative 

 psychology. In these creatures we see, as nowhere else, how 

 activities that seem so complicated and varied as to require 

 psychological powers of a high order, are produced merely 

 through one or two simple reflexes ; it seems not impossible 

 that the phenomena exhibited in the conduct of these organ- 

 isms may in time furnish important points of support for the 

 general theory of the origin and development of psychic 

 powers. 



