4 6 THE PSYCHIC LIFE 



study. If a drop of water containing Infusoria be 

 placed under the microscope, organisms are seen 

 swimming rapidly about and traversing the liquid 

 medium in which they are in every direction. Their 

 movements are not simple; the Infusory guides itself 

 while swimming about; it avoids obstacles; often it 

 undertakes to force them aside; its movements seem 

 to be designed to effect an end, which in most instances 

 is the search for food; it approaches certain particles 

 suspended in the liquid, it feels them with its cilia, it 

 goes away and returns, all the while describing a zig- 

 zag course similar to the paths of captive fish in 

 aquariums; this latter comparison naturally occurs to 

 to the mind. In short, the act of locomotion as seen 

 in det-ached Infusoria, exhibits all the marks of volun- 

 tary movement. 



It might also be mentioned that every species 

 manifests its personality in its mode of locomotion. 

 Thus, as a rule, the Actindtricha saltans when placed 

 in a preparation where it finds itself at ease, remains 

 for a few moments perfectly immovable. Then, of a 

 sudden, it dashes forward with the rapidity of light- 

 ning and disappears from the field of vision. For a 

 time it darts about to the right and to the left, and 

 then once more assumes its state of immobility. It 

 can move with the greatest agility through masses of 

 debris, in the midst of which, bending and twisting, it 

 slips about with wonderful nimbleness. The Lagynus 

 crassicolis, on the other hand, moves along at a pace 

 quite constant and uniform, neither slow nor rapid. 

 It searches about among algae and fragmentary parti- 

 cles. The Peritromus Emma moves slowly. "It runs 

 lazily over the Algae, where it seeks its nutriment, and 

 does not stray from them to venture into the open water. 



