Cancer. 397 



epithelial cells, retaining their power of proliferation, occurs. It is 

 of course true that inflammations of surfaces covered by epithelium 

 and epithelial organs are frequently seen without resultant cancer 

 production, even though it may be presumed that isolations of 

 epithelial cells may often obtain in connection with these processes. 

 But, as Ribbert insists in case of such exceptions, much depends 

 upon the length of time over which the inflammation extends. In 

 acute inflammations the epithelium is apt to be injured, and even if 

 isolated cells be misplaced in the subjacent tissues the process is of 

 too short duration to allow the cells to accommodate themselves to 

 their new surroundings; they therefore perish (Ribbert). In the 

 same way as an inflammatory connective tissue production, epithe- 

 lial cells may in papillary and polypous new* growths be cut off and 

 isolated by the proliferation of the stroma, or whole cores or 

 bunches of them : and thus a primarily benign tumor may be con- 

 verted into a malignant one by the progressive growth of such 

 cells into the underlying tissues. The change of fibroepithelial 

 growths which for years have been of simple type into destructive 

 cancers is a well authenticated observation in human medicine. 

 Finally, epithelial misplacements, which may accidentally be caused 

 in foetal life in the processes of arrangement of the various tissues, 

 in the formation of folds and cavities which are taking place 

 among the tissues in the construction of the various organs, may 

 furnish the original substance for a subsequent cancer. 



A good example of this is afforded by the nodular growths met in the 

 human kidney cortex, originating from misplaced adrenal tissue. They are 

 met as single or multiple growths, well defined; and sometimes destroy the 

 kidney, penetrate into the blood vessels, and give rise to fatal metastasis. 

 These nodes are of a yellowish color from the fat which they contain, and 

 under the microscope are seen to be made up of cords of cells arranged 

 in parallel lines along the blood vessels, and resembling in their appearance 

 the epithelium of the suprarenal bodies (hypernephroma, adrenal cancer). 

 LThese growths are also met with not very infrequently in the kidneys of 

 cattle and occasionally in hogs; they are not confined to the kidney, but 

 may be found in any of the structures near the adrenals or in the adrenals 

 themselves, where they may either represent foetal rests, or may have started 

 from isolated parts or inclusions of the tissue of the organ caused by inflam- 

 matory sejparations.] 



Ribbert's attempted explanation of the genesis of cancer is not 

 as vet accepted by many pathologists. Inflammatory changes are 

 often not demonstrable at the places of origin of cancers ; and some 

 authors do not believe that the atypical proliferation of the epithe- 

 lium is a result of the invasive growth of the comiective tissue but 



