INTERNAL OR MUCOUS COAT OF THE BLADDER. 133 



dermis ; and some respectable authors have supposed that they 

 had seen cases in which portions of the epidermis of the bladder 

 had separated and been discharged ; but these appearances are 

 very equivocal, and it is by no means certain that an epidermis 

 exists there.* 



The fasciculi of fibres of the muscular coat occasion this 

 coat to appear very irregular, but these irregularities correspond 

 exactly with the arrangement of the fibres of the muscular coat. 



When the internal coat is separated by dissection from the 

 muscular, its surface is very smooth and uniform. In the recent 

 subject, when no disease has previously existed, it is always 

 spread over with mucus of a light color, but nearly transparent, 

 which can be easily scraped off. This mucus is spread upon 

 the surface so uniformly, that it must be derived from sources 

 which are situated upon every part of the surface ; but these 

 sources are not very obvious. On the membrane of the nose 

 the orifices of many mucous ducts are very visible, but such 

 orifices are not to be seen on this surface. Haller mentions 

 that he has seen mucous glands near the neck of the bladder; 

 and it is stated by the pupils of Desault, that, in one of his 

 courses, he pointed out a number of these glands, in a subject 

 who had been afflicted with a catarrhal affection of the bladder. 



Notwithstanding that the sources of this mucus are obscure, 

 the quantity of it is sometimes immense. In some cases, where 

 the secretion is increased by the irritation of a calculus in the 

 bladder, the urine is rendered somewhat viscid and white- 

 colored by the mucus mixed with it ; which, after the urine 

 has been allowed to remain for some time, subsides in such 

 quantities as demonstrates that many ounces must be secreted 

 in the course of the twenty-four hours. The same circum- 

 stances occur without the irritation of calculus, in the disease 

 called catarrhus vesicae.f 



It is probable that, in healthy persons, a great deal of it 

 passes off unperceived, being dissolved or diffused in the urine. 



* In the fauces and the follicles of the tonsils, an effusion of coagulable 

 matter, in consequence of inflammation, often forms crusts that may be mis- 

 taken for sloughs of the integuments, although these integuments remain entire. 



f In some cases this mucus soon becomes putrid, and during the putrefactive 

 process deposits its substance which appears to be calcareous. 

 VOL. II. 12 



