PSYCHIC GEADATIONS. Ill 



phylogenetic connection, has only been seriously 

 attempted during the last ten years, especially in 

 the splendid work of Romanes. We must confine 

 ourselves here to a brief discussion of a few of the 

 general questions which that gradation has suggested. 

 All the phenomena of the psychic life are, without 

 exception, bound up with certain material changes in 

 the living substance of the body, the protoplasm. We 

 have given to that part of the protoplasm which seems 

 to be the indispensable substratum of psychic life the 

 name of psychoplasm (the " soul-substance," in the 

 monistic sense) ; in other words, we do not attribute 

 any peculiar ''essence" to it, but we consider the 

 psyche to be merely a collective idea of all the psychic 

 functions of protoplasm. In this sense the "soul" is 

 merely a physiological abstraction like " assimilation " 

 or " generation." In man and the higher animals, in 

 accordance with the division of labour of the organs 

 and tissues, the psychoplasm is a differentiated part 

 of the nervous system, the neuroplasm of the 

 ganglionic cells and their fibres. In the lower 

 animals, however, which have no special nerves and 

 organs of sense, and in the plants, the psychoplasm 

 has not yet reached an independent differentiation. 

 Finally, in the unicellular protists, the psychoplasm 

 is identified either with the whole of the living 

 protoplasm of the simple cell or with a portion of it. 

 In all cases, in the lowest as well as the highest stages 

 of the psychological hierarchy, a certain chemical 

 composition and a certain physical activity of the 

 psychoplasm are indispensable before the "soul" 

 can function or act. That is equally true of the 

 elementary psychic function of the plasmatic sensa- 

 tion and movement of the protozoa, and of the 



