3(50 nm.osuriiY 01 /ooi.nc.v. 



secretes a lubricating fluid, to protect tin- ornan In mi the 



aciion of the contained flui<l. The ureters enter the blmddei 



towards its mouth on the dorsal side, passing through its 

 CORtH in an mdiretl ;ind tortuous manner. The bladder 

 itself is retained in its place, partly by the folds of tin- pe- 

 ritoneum, :uid partly l>y its own li^aincnls. r rlu-sc cillu-r 

 arise from llir mrk of llic bladder, and an- allaclu-d lo the 

 |>ul)is, or from its I'midus, constituting tlie unicluis. Tlir 

 urine, at slated intervals, is < xjielled from the bladder, 

 thmii;;h a canal termed the v//r////v/, \\hich accoin|)anies 

 the reproductive organs. 



The inodilications of this system in the inferior classes of 

 animals, are numerous. In none of them do the kidneys in 

 their struct ure appear lo consist, of two parts. The ureters, 

 \\lnle they pour their contents into a bladder of urine, in 

 some reptiles and fishes, do not, in others, terminate in any 

 common re ccptacle. In birds, in general, and many reptiles 

 and fishes, the urine, before expulsion from the body, is mix- 

 ed \\ith the excrement, while in many fishes, it either passes 



out by a peculiar opening, or in a common passage with 

 (lie melt or spawn. Nothing analogous to urinary organs 

 has yet been detected in the mollusca or annulose animals, 

 although in the duii of the caterpillars of several insects, 

 traces of the peculiar principle of urine, or urea, ha\e been 



detected. 



There is a singular compound body adhering to the upper 

 part of the kidney in quadrupeds, termed the renal glttmli 

 whose use is unknown. It is of a yellowish colour 

 and linn consistence, ami frequently contains a cavity filled 

 with a dark serous fluid. In the fcrtus, it is equal in 

 si/e to the kidneys, but. in the adult, it is about one- 

 fifth less. 



The urine itself has been repeatedly examined by diffe- 

 rent chemists, and a variety of products obtained from its 



