504 On the Cells of Malignant Growths in Man. [Dec. 8, 



the remote cause must be sought for amongst those various stimuli, 

 some of which, e.g., continuous irritation, are known to favour their 

 development. 



Malignant growths seem, furthermore, to be definitely separable 

 from benign tumours, inasmuch as in the latter we have never 

 succeeded in discovering anything resembling the very characteristic 

 nuclear changes we have described above. Thus, inter alia, while we 

 have in the example of a polypoid papilloma observed a considerable 

 number of somatic mitoses with the full (unreduced) number of 

 chromosomes, we have been wholly unable to find a single instance 

 of a heterotype division, or anything indicating that a reduction in 

 the number of chromosomes had taken place. 



In this preliminary communication we do not propose to deal, 

 except in the most brief manner, with such questions as the probable 

 transmission of the disease from one individual to another, or to its 

 prevalence in certain districts, or even in certain houses. 



It seems probable that actual contact does in some cases transmit 

 the disease, but it is apparently equally probable that this happens 

 where cells from the growth are transplanted to another part of the 

 same individual, or to another individual under very peculiar con- 

 ditions, which allow of the repeated application of a suitable stimulus, 

 or of the continuous introduction of cells which have undergone the 

 changes- we have described. 



In the case of localities where malignant growths are apparently 

 prevalent, e.g., cancer houses, the phenomenon is directly comparable 

 to the occurrence of abnormal cellular developments under suitable 

 stimuli to which we have already referred. 



In conclusion we would point out that the various changes which 

 we have described as occurring in cells are always rapid, and possibly 

 hastened during the approaching death of the tissue. Unlese, there- 

 fore, the tissues are treated in such a manner as to fix the cells com- 

 posing them some time before death supervenes, the nuclei will be 

 found either in a condition of rest or in one of more or less disintegWk- 

 tion. We have emphasised this fact because, in the ordinary 

 pathological methods of preparing specimens, it has not hitherto been 

 found necessary to make proper provision for the preservation and 

 fixation of the cells, either with regard to time or suitable reagents. 

 Such preparations, though, of course, admirably suited for ordinary 

 histological investigation, are not suitable for elucidation of the finer 

 cytological characters of the individual cells. 



We cannot bring this communication to a close without expressing 

 our great indebtedness to Dr. W. E.. Dakin and to Messrs. Allingham, 

 Baldwin, English, Jaffery, Parsons, Shield, and others, who, by so 

 kindly enabling us to obtain the necessary material, have made this 

 investigation possible. 



