182 CARCINOMATA. 



epithelial coat of the papillae is at the same time the epi- 

 thelial lining of the interpapillaiy fissures ; and so long as this 

 condition is maintained in statu quo by an adequate shedding 

 of the older epithelial cells, the growth preserves its hyperplastic 

 character. The longer the papillas become, however, more 

 especially if they break up into dendritic vegetations, the greater 

 must obviously be the impediment to the adequate removal of 

 the older cells. The lateral pressure exerted by the apices of the 

 papillae, whose terminal ramifications spread out widely, while 

 they rest upon a very narrow base, shuts in the interpapillary 

 fissures from above and consequently determines a gradual and 

 progressive accumulation of epithelial elements in their interior. 

 In the deeper parts of the tumour, the epithe^um soon ceases to 

 be a mere lining ; it forms a solid mass wliich fills the inter- 

 papillary fissures. In this capacity it now begins to burrow at 

 various points into the underlying connectivd tissue. Elongated 

 cylinders of epithelial cells make their appea'ance ; at first, they 

 simply project into the cutis from the under surface of the 

 epidermis ; subsequently penetrating more and more deeply 

 into it. The carcinomatous condition is thereby definitely estab- 

 lished. It were indeed impossible to overlook the resemblance 

 between these tap-shaped epithelial ingrowths, and those which 

 take part in the development of glands ; moreover, as has been 

 already stated, the constituent cells are seen to undergo active 

 fission ; nevertheless, I shall continue to maintain, until the con- 

 trary has been proved, that their gro'v^th, like that of normal 

 epithelia, is primarily due to a peripha'al apposition of young 

 cells; and this hypothesis seems to me quite as plausible as that 

 of the enlargement of retention-cystsj by secretion from their 

 walls. The fissiparous multiplication Hiich takes place in the 

 interior of the epithelial sprouts is indicative of a secondary 

 growth ; it may even contribute mostlto their increase in thick- 

 ness ; but it has no share in their elongation, in that inward 

 growth of the sprouts, to which the :lestruction of the affected 

 organs is actually due. This subjecf will be more fully treated 

 in the sections devoted to squamous epithelioma ; the object of 

 these preliminary remarks being to direct attention to the fact 

 that the laws of normal growth retan their force even in these 

 most extreme and perilous departure! from the normal type. 



