1905.] 



On the Cytology of Malignant Grotvths. 



351 



becomes necessary therefore to seek for some other explanation for the 

 phenomena actually witnessed. 



It is quite certain, in the first place, that we are dealing with the trans- 

 formation of functional somatic cells into cancerous ones, and this, to our own 

 minds, affords a complete refutation of the hypothesis as to the persistence of 

 " embryonic rests," such as have been supposed by Cohnheim and his followers 

 to account for the incidence of the disease. 



We have drawn attention to the events that occur in connection with the 

 invasion of the cells of the young growths by leucocytes, and, although we 

 are fully aware that further investigations into the details of these processes 

 are required before a final opinion can be expressed as to their true significance, 

 the facts themselves are very suggestive. 



Furthermore, the interest attaching to these fusions is not lessened by a 

 study of the bone-marrow, in which the leucocytes can be most advantageously 

 observed. For we have seen in this tissue all the abnormal types of nuclear 

 and cellular division that are so highly characteristic of cancerous cells, and 

 we have ascertained a fact of even greater importance, namely, that some 

 of the nuclei of dividing marrow cells certainly possess less than the full 

 complement (32) of somatic chromosomes. We would, further, lay emphasis 

 on the occurrence, in the same preparations of bone-marrow, of other cells in 

 which the process of mitosis was strictly somatic in character, both as regards 

 the form and number of the chromosomes. But it is none the less certain 

 that the other nuclei exhibit chromosomes of a remarkable form, elongated in 

 the direction of the spindle, and strongly resembling those which are so 

 characteristic of the heterotype mitoses of the testis or of a cancer. 



Whilst it is obvious that further investigation on the cytology of bone-marrow 

 is urgently needed, it is evident that, if it should ultimately prove that the cells 

 which are derived from the results of fusion of a leucocyte with a tumour 

 cell really represent the progenitors of the malignant elements themselves, a 

 satisfactory explanation would be afforded not only of the striking nuclear 

 character of the diseased tissues, but also of the invasive and destructive 

 powers they undoubtedly possess. The destructive action of the leucocytes 

 themselves on other cells of the body, especially during old age, is too well 

 known, owing especially to the valuable researches of Metschnikoff, to call 

 for further comment here. 



Such a view of the case as is here tentatively suggested is not in 

 conflict with the idea embodied in the term " gametoid " tissue, but rather 

 forms an extension of it. We have, as already pointed out, from the first 

 maintained the existence of a resemblance, extending to extraordinarily 

 minute detail, between the " gametoid," cancerous, and the reproductive tissue, 



