1905.] On the Cytology of Malignant Growths. 



341 



But the strongest proof of the persistence of the leucocyte under these 

 remarkable conditions is afforded by the cases, not few in number, in which we 

 have been able to trace the leucocyte actually dividing within the cancer cell 

 (figs. 12, 13). Of course, it is only during the early stages that it is possible to 

 be certain that a second dividing nucleus in a mass of protoplasm belongs to a 

 leucocyte, and does not represent mitosis in a small nucleus that has arisen 

 by fragmentation. But we have seen so many eases of early stages of leuco- 

 cytic mitosis within the cancerous (or " precancerous ") cell that it seems 

 impossible to resist the inference that many of those frequently occurring 

 cases in which a small nucleus is seen in the later phases of mitosis within the 

 large nucleated cancer cell are to be attributed to this source. The nuclei of 

 the cancer cell and leucocyte often divide simultaneously, and the two nuclear 

 figures may also coalesce more or less intimately, and thus a commingling of 

 leucocytic and epithelial chromosomes occurs on a spindle that becomes 

 common to the two nuclei concerned. The cells so affected were, as already 

 stated, usually the very large (giant) cells so characteristic at this stage of the 

 development of the tumour, and we found that more than one leucocyte might 

 ■enter and persist in a single cancer cell. In the earlier stages, of course, 

 there is no difficulty in clearly recognising the intruding cell, since it retains 

 its own cytoplasm and limiting membrane intact (see fig. 11), and the highly 

 characteristic structure of the nucleus enables it to be identified even after 

 these criteria have ceased to exist. 



In the same region in which this series of events is proceeding a number of 

 cancer cells are to be seen in various phases of mitosis, and, both in the aster 

 and diaster of such nuclei, larger numbers of chromosomes were often 

 encountered than are proper to normal somatic cells. These increased 

 numbers are partly to be ascribed to the pluripolar mitosis distinguished by 

 Hertwig and by Von Hansemann, and they result from the simultaneous 

 mitosis of a number of nuclei lying in a common cytoplasmic mass. 



But the observations recorded above indicate that, in the addition of 

 leucocytic nuclei to those of the actual epithelial cells, we have confronted, 

 at any rate, with one of the sources to which these excessive numbers of 

 chromosomes (hyperchromatic nuclei of Von Hansemann) may be attributed, 

 although a large number of the cells continue to multiply in the manner 

 already described, it may also be seen that there exists a very considerable 

 amount of amitosis, or direct nuclear divisions in the cells of the young parts 

 of the tumour. There appears to be no evidence which would point to the 

 conclusion that amitosis is in any way bound up with degeneration, or 

 diminishing activity in those cells in which it occurs. Elements that have 

 previously multiplied by amitosis and by fragmentation have given rise to 



