CAULIFLOWER TUMOURS. 515 



whether the formation only involves the surface, or 

 whether it is complicated with disease of the subjacent 

 tissue. There are certainly at the present time very 

 many anatomists and surgeons who entertain the notion 

 that cells may grow on the surface exactly similar to 

 those which are usually only found in the interior of dis- 

 eased organs that, for example, a villous tumour must 

 be termed cancerous, if it is covered over with cancer- 

 cells as with an epithelium, without any development of 

 cancerous matter having shown itself in the interior 

 of the villi. In fact, villi, which are very delicate and 

 scarcely contain enough connective-tissue to envelop the 

 vessels that run up in them, are sometimes met with, 

 enclosed in a thick layer of cells which, from the irregu- 

 larity of their form, the size of their nuclei, and their own 

 large dimensions, present rather the character of cancer 

 than that of epithelium. But I must confess that I have 

 not as yet been able to convince myself that cancer-cells 

 are able to arise upon the free surfaces of membranes, 

 and that they can be produced simply from epithelium ; 

 on the contrary, I believe from all that I have seen, that 

 a very strict line of demarcation must be drawn between 

 the cases, where masses of cells, however abundant and 

 curiously shaped they may be, are found seated upon a 

 basis-tissue in itself unaltered, and those, where the cells 

 have been formed in the parenchyma of the parts them- 

 selves. 



The pathological importance of a papillary tumour is, 

 at least as far as I know, determined by the condition 

 of its basis-substance, or by that of the parenchyma of the 

 villi themselves ; and a formation can only be pronounced 

 to be cancroid or carcinoma when, in addition to the 

 growth of the surface, the peculiar degenerations which 

 characterize these two kinds of tumours, take place also 

 in the deeper layers or in the villi themselves. I think, 



