70 CELL INTELLIGENCE THE CAUSE OP EVOLUTION 



and will power of the cell. In regard to this part of the 

 cell Prof. Wilson makes the following statement : "From 

 our present point of view, the centrosome possesses a 

 peculiar interest as a cell organ which may be scarcely 

 larger than a cytomicrosome, yet possesses specific 

 physiological properties, assimilates, grows, divides and 

 may persist from cell to cell without loss of identity. 

 Nearly all observers of the centrosome have found it 

 lying in the cytoplasm outside the nucleus, but apart 

 from the protozoa there is at least one established case 

 in which it lies within the nucleus, a fact that proves 

 that its position is nonessential ; that the centrosome is 

 an active center rather than a passive body or one created 

 by the aster formation is strongly indicated by its be- 

 havior." 



Then Prof. Wilson after having stated the general func- 

 tions of the centrosome, sums up in the following lan- 

 guage : "These facts seem explicable only under the 

 assumption that in these cases the centrosome or the 

 substance which it carries gives an active stimulus to the 

 cytoplasm, which incites the aster formation about itself 

 and in words of Griffin disengages the forces at work in 

 mitosis. 



"The centrosome must, however, be something more 

 than a mere division center, for on the one hand in leu- 

 cocytes and pigment cells, the astral system formed about 

 it is devoted, as there is good reason to believe, not to 

 cell division but to movements of the cell body as a 

 whole, and on the other hand, as we have seen, it is con- 

 cerned in the formation of the flagella of the spermato- 

 zoon and probably also in the cilia of epithelial cells." 

 You will see from this, that the centrosome is the party 

 in the cell who seems to direct its several actions. It will 

 also appear that the centrosome leads a separate life 



