PAPILLOMATA, (CONDYLOMATOUS AND CANCEROUS). 513 



The papillae consists of connective tissue like the skin, or 

 the mucous membrane, upon which they are seated ; 

 within the papillae therefore a cancerous mass may 

 develop itself out of the connective tissue, as out of the 

 connective tissue of the skin or mucous membrane. 

 Moreover, it cannot be denied that this peculiarity of 

 superficial formation very frequently explains certain 

 peculiarities in the course of the disease, whereby a papil- 

 lary tumour is strikingly distinguished from the same 

 kind of tumour when not papillary. Any one may have 

 a cancer of the bladder if it be merely seated in the pa- 

 rietes for a very long time, without any other changes 

 being necessarily displayed in the nature of the secretion, 

 which must be evacuated with the urine, than those 

 exhibited in a simple catarrh. As soon, on the contrary, 

 as a formation of villi takes place upon the surface, nothing 

 is more common than for hematuria to arise as a com- 

 plication, from the simple reason, that every villus upon 

 the walls of the urinary bladder is not clothed with a 

 firm layer of epidermis, but lies almost bare under a 

 loose epithelial covering. Into the interior of the villi 

 ascend large vascular loops which reach quite up to the 

 surface, and therefore very considerable mechanical irri- 

 tation supplies a condition for the production of hy- 

 peraemia and the rupture of the villi. A spasmodic 

 contraction of the bladder drives the blood up into the 

 apices of the villi, in consequence of the shortening of the 

 surface on which they are seated, and when to this is 

 added the mechanical friction of the surfaces, nothing is 

 more likely to ensue than a sometimes more, sometimes 

 less considerable effusion of blood. But in order that 

 such haemorrhage should take place it is altogether unne- 

 cessary that the papillary tumour should be cancerous. I 

 have seen cases in which, for years, uncontrollable bleed- 

 ings recurred from time to time, through which at last the 



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