THE PHYLOGENY OF THE SOUL. 159 



repeated in substantially the same manner in the 

 process of ordinary (indirect) segmentation of cells 

 (formation of the axis of the nucleus, mitosis, karyo- 

 kinesis, etc.) ; (2) the outer movements, which are 

 seen in the regular change of position of the social 

 cells and their grouping for the construction of the 

 blastoderm. We assume that these movements are 

 hereditary and unconscious, because they are always 

 determined in the same fashion by heredity from the 

 earlier protist ancestors. The sensations, also, fall 

 into two gronps : (1) the sensations of the individual 

 cells, which reveal themselves in the assertion of their 

 individual independence and their relation to neigh- 

 bouring cells (with which they are in contact, and 

 partly in direct combination, by means of protoplasmic 

 fibres) ; (2) the common sensation of the entire com- 

 munity of cells which is seen in the individual forma- 

 tion of the blastula as a hollow vesicle. 



The casual interpretation of the formation of the 

 blastula is given us by the biogenetic law, which 

 explains the phenomena we directly observe to be the 

 outcome of heredity, and relates them to corresponding 

 historical processes which took place long ago in the 

 origin of the earliest protist-ccenobia, the blastseads. 

 But we get a physiological and psychological insight 

 into these important phenomena of the earliest cell- 

 communities by observation and experiment on their 

 modern representatives. Such permanent cell-com- 

 munities or colonies are still found in great numbers 

 both among the plasmodomous primitive plants (for 

 instance, the paulotomacea, diatomacea, volvocinse, 

 etc.) and the plasmophagous primitive animals (the 

 infusoria and rhizopods). In all these coenobia we 

 can easily distinguish two different grades of psychic 



