I^O BIOLOGICAL LECTURES. 



not the stimulus that determines the functional results. " Cer- 

 tain agents set up a reaction in the animal, the directive features 

 of which depend entirely upon the structure of the organism. "^ 



This author's conclusion is particularly interesting both in 

 its originality and its bold denial of the conclusions of other 

 observers, and the support it gives to the opinions expressed in 

 this paper with regard to the necessity of considering evidence 

 of all kinds from the point of view of the position or grade of 

 the animal. Speaking of one of the most highly organized of 

 the Protozoa, Paramecium, with which he has become very 

 familiar by long-continued study, he says : " An animal that 

 learns nothing, that exercises no choice in any respect, that is 

 attracted to nothing and repelled by nothing, that reacts en- 

 tirely without reference to the position of external objects, that 

 has but one reaction for the most varied stimuli, can hardly be 

 said to have made the first step in the evolution of mind, and 

 we are not compelled to assume consciousness or intelligence 

 in any form to explain its activities." If Jennings is correct, 

 this highly differentiated protozoon is a zero point in the evolu- 

 tion of consciousness. Whether, however, this is due to the 

 essential character of its protozoanal or unicellular structure 

 or to the loss of functional power cannot be asserted until 

 the simpler forms of Protozoa have been studied in the same 

 thorough way and with corresponding tests of their internal 

 reactions. 



The importance of these researches, if confirmed and estab- 

 lished, can hardly be overestimated, since they open the way 

 for experimental observation upon the evolution of intelligence, 

 and, if found to be true in simpler organisms, will show that 

 automatic habits come first in the evolution of consciousness, 

 and are not, as often supposed, invariably the results of repeated 

 conscious actions.^ 



A number of other recent papers and books have shown that 

 psychology has its obvious place in the study of organisms, but 



1 " Psychology of a Protozoon," Am.jojcrn. of Psychol., vol. x, No. 4, 1S99, p. 51 3. 



2 This does not imply that automatism is not a retrogressive result of the 

 constant repetition of conscious actions, but simply that it is also a primitive or 

 antecedent stage in the progressive evolution of consciousness. 



