OF MICRO-ORGANISMS. 61 



v. 



It is difficult in the extreme to mark out the lines 

 of a psychology of Proto-organisms from data so in- 

 complete as those we have just collected. We shall 

 content ourselves with a few brief considerations. 



The apparent result of our investigations up to this 

 point is, that the greater number of movements and 

 actions observed in Micro-organisms are direct re- 

 sponses to excitations emanating from the medium in 

 which they live. It is the condition of the medium that, 

 to all appearance, rigidly determines the character and 

 manner of their activity; in a word, they exhibit no 

 marks of pre-adaptation. 



But it will not do to let the matter rest with this 

 general survey of the subject; we shall have to examine 

 more closely each detail of these reflex actions of adap- 

 tation, beginning with the sensory phase and ending 

 with the motory phase. Analysis discloses that sev- 

 eral determining elements may be distinguished in 

 these phenomena; they are: 



1. The perception of the external object; 



2. The choice made between a number of objects; 



3. The perception of their position in space; 



4. Movements calculated, either to approach the 

 body and seize it, or to flee from it. 



We are not in a position to determine whether these 

 various acts are accompanied by consciousness or 

 whether they follow as simple physiological processes. 

 This question we are obliged, for the present, to forego. 



i. The perception of an external body. Among the 

 lowest forms, it appears that perception is always the 

 result of a direct irritation produced by contact of the 

 external body with the protoplasm of the animalcule. 

 This is what takes place, to all appearance, among the 



