THEORIES OF CYTOGENY 177 



lower animals which have been subjected to certain 

 alkaloids, such as quinine, nicotine, and cocaine, and 

 also to antipyrene, the mitotic figures may be of the 

 asymmetrical type, and that in the case of certain epi- 

 thelial cells of salamanders the mitotic divisions which 

 occur in the presence of these substances closely re- 

 semble the asymmetrical divisions seen in human 

 cancer-cells. These points took us back once more 

 to our own knowledge that alkaloids excited leuco- 

 cytes; but we have never seen divisions, asymmetrical 

 or otherwise, actually induced in leucocytes by any 

 alkaloid or other substance. 



Farmer, Moore, and Walker had closely studied 

 the cytology of cancer-cells. They had frequently 

 seen cells in the act of division in their stained speci- 

 mens, and they described the asymmetrical "maiotic" 

 mitoses by which cancer-cells frequently appear to 

 divide. By the expression "maiotic division" a "re- 

 duced" division is meant; that is to say, that a cell 

 divides with a reduced number of chromosomes, and 

 instead of having its customary somatic number, that 

 number may be reduced to one-half. In man the 

 somatic number of chromosomes is thirty-two, and 

 cancer-cells sometimes divide with sixteen chromo- 

 somes. Farmer, Moore, and Walker also describe 

 other characteristics of the several maiotic phases of 

 mitosis, and they specify two forms of maiotic di- 

 vision namely, the first change in a cell's life- 

 history from its somatic division to the maiotic, which 

 they call the first (heterotype) maiotic division, and the 

 succeeding maiotic divisions of its life-history, which 



