240 THE CYCLE OF CELL-DIVISION 



that the wandering cells of the body only divide by 

 reduced divisions of the "reproductive" type is thereby 

 disproved. In lymphocytes examined on a microscopic 

 slide the question of the number of chromosomes seems 

 to be entirely one of degree it depends on the rapidity 

 of the division, which, in its turn, depends on the 

 quantity of the "auxetic" absorbed by the cell. By 

 increasing the alkali one can induce divisions very 

 quickly, provided of course there is not too much 

 alkali. We have seen lymphocytes divide with less 

 than sixteen chromosomes, and on one occasion, when 

 mitosis was very rapidly induced, the number was 

 reduced to eight only; but the number of chromo- 

 somes seems usually to remain in these round numbers, 

 namely, thirty-two, sixteen, eight, the last one being 

 very rare. If a division is induced in the usual way 

 with a jelly w T hich will kill the cells in about ten 

 minutes, the number of chromosomes is nearly always 

 sixteen, but a slow division will be a somatic division. 

 There does seem, however, to be a difference in the 

 way the chromosomes split. We have seen them in 

 the act of splitting longitudinally, and also, and more 

 commonly, they split transversely; although Avhether 

 the longitudinal splitting is significant of a "first 

 (heterotype) maiotic" division or not we are not in 

 a position to state. 



The asymmetrical mitoses induced when atropine 

 is present, especially if it is present to excess, are 

 interesting. The mitosis seems to be going on in 

 one side of the cell. We have not seen a completed 

 division in one of those asymmetrical mitoses, but we 



