158 CONSTRUCTION OF THE BLADDER ; [BOOK I. 



several diseases in the horses confined in them — 

 glanders among the rest. 



56. The bladder, or receptacle for the re- 

 dundant water of the whole system, as it is se- 

 parated from the blood by the kidneys, is situated 

 within the hollow of the os pelvis, at the intersec- 

 tion of H with 34 on the plate of a skeleton, 

 with its outlet or neck turned towards the place 

 of exit, varying a little according to 

 the sex. It consists of three coats or 

 layers, (see Jig.) the outer two being 

 muscular, and having their fibres cross- 

 ing each other — (as may be seen upon 

 splitting it asunder, being most appa- 

 rent), in a stale bladder, the better to 

 enable it to contract upon^ and expel its 

 contents. The inner coat is membranous, sen- 

 sible on distension, and secreting an unctuous or 

 mucous fluid to protect itself against the stimulating 

 effects of the urine. When, however, the bladder 

 becomes full, the secretion is insufficient for its 

 protection, and extreme irritation ensues, in order 

 to induce the muscular coats to concur in the ex- 

 pulsion of the urine. This desire must be very 

 great in the horse, for the reason assigned at the 

 close of the preceding section, and shows the neces- 

 sity of permitting him to stale upon his first inti- 

 mating an inclination thereto. The shape of some 

 horses' bladders differs a good deal from that of 

 others, — particularly about the neck, those of the 

 female being always considerably wider, and shorter, 



