MOVEMENT 



the "dominants," in the« actual direction of their move- 

 ments, as much as he does in the plasma-flow in the 

 tiny organism. 



The manifold gradation of vital movement which we 

 find everywhere in the higher organisms is not without 

 expression even in the protist realm. In this respect 

 the chromacea, the simplest forms of vegetal monera, 

 and the bacteria, which we regard as corresponding 

 animal forms, developed from the former by metasitism, 

 are of great interest. As microscopic scrutiny fails to 

 detect any purposive organization in these unnucleated 

 cells, and it is impossible to discover different organs in 

 their homogeneous plasma-body, we have to look upon 

 their movements as direct effects of their chemical 

 molecular structure. But the same must be said also of 

 a number of nucleated cells, both among the protoph- 

 yta and the protozoa; only in this case the structure 

 is less simple, in so far as both the nucleus itself and the 

 surrounding cell-body exhibit, in indirect division, com- 

 plicated movements in the plasm (caryokinesis). Apart 

 from these, however, there is nothing to be seen in many 

 unicellular beings {e.g., paulotomea, or calcocytea) that 

 we need call "vital movement." On the border between 

 the organic and inorganic worlds we have, as regards 

 movement, the simplest forms of the chromacea, chroo- 

 coccacea. We can see no vital movement in these 

 structureless particles of plasm except slight changes of 

 form, which occur when they multiply by cleavage. The 

 internal molecular movements of the living matter, 

 which effect their simple plasmodomous metabolism and 

 growth, lie beyond our vision. The reproduction itself, 

 in its simplest form of self -cleavage, seems to be merely 

 a redundant growth, exceeding the limit of individual 

 size for the homogeneous plasma - globule {cf. chapters 

 ix. and x.). 



The great majority of the protists have the appear- 

 267 



