MITOSIS OF LEUCOCYTES 269 



them, as only early stages of mitosis were seen in 

 them. Hence it became apparent that the auxetic 

 constituent of the aniline dye which induces divisions 

 in lymphocytes also does the same thing with leucocytes ; 

 but it evidently requires more of it, ceteris paribus, 

 to induce a division in a leucocyte than in a lymphocyte. 

 The coefficient of diffusion of the lymphocyte is higher 

 than that of the leucocyte if the staining of the nucleus 

 is the moment by which it is determined; but so far 

 as inducing divisions is concerned the coefficient of 

 lymphocytes seems to be lower, for they require less 

 of the chemical agent than do leucocytes. 



The divisions of reproduction had now been induced 

 in both leucocytes and lymphocytes by an artificial 

 chemical agent. These cells are the ones which pro- 

 liferate when a tissue is damaged, and it is by their 

 multiplication that the healing of an injury takes place, 

 and it must be borne in mind that cancer, with its in- 

 creased malignant proliferation, is intimately associated 

 with chronic healing. Judging by the divisions induced 

 in these white blood-corpuscles it appeared that their 

 reproduction takes place in a cycle which depends on 

 some chemical substance absorbed by them. The cycle 

 consists apparently of the division of the centrosomes, 

 division of the chromosomes, and the division of the 

 cell. Whether there is a "resting stage" in the strict 

 sense of the term, we are not in a position to state, 

 for we do not know how long a time is occupied in 

 the division of the centrosome. If a cell is absorbing 

 the agent which causes it to divide, presumably the 

 cycle of mitosis is going on in direct proportion to the 



