202 ANTHROPOLOGY. 
on the rectum. It possesses muscular fibres, and a cervical sphincter. The 
different regions have received different names, as the superior fundus, for 
the superior anterior extremity; wm/ferior fundus, the posterior extremity 
resting on the rectum; the dody, the intervening portion; and the cerwz, the 
portion connected with the pubes, above the rectum. 
4. THE URETHRA. The urine is discharged from the bladder by the 
urethra, a membranous tube, which in the male extends to the extremity of 
the penis; and in the female opens into the vagina, behind and below the 
clitoris. | | 
The principal constituent of urine is water. When evaporated, the 
residuum consists principally of urea, uric and hippuric acids; substances 
containing a very large amount of nitrogen. Food, mode of life, &., greatly 
affect the nature of the urine. The presence of lactic acid is denied by 
some authors. Extractive matters are present, especially during a vegetable 
diet, also certain mineral substances, as phosphoric and sulphuric acids, 
alkaline carbonates, earthy phosphates, and chlorides. The sulphuric acid 
combinations enter in greatest amount, and to a larger extent, under a 
purely animal diet, than when the food is more miscellaneous. 
Urine is generally acid; occasionally, however, it is alkaline, and it 
always exhibits a conversion of its urea into carbonate of ammonia during 
putrefaction. Certain substances are readily eliminated from the blood by 
the kidneys; others with more difficulty or not at all. Alcohol, sulphurie 
ether, camphor, musk, and many vegetable colors, are not removed from the 
blood. On the other hand, carbonates, sulphates, chlorates, and nitrates of 
potassa, coloring matter of indigo, musk, castoreum, assafcetida, &c., are 
entirely separated. An intermediate class undergoes a transformation before 
eJimination. 
Pl. 180, fig. 19, exterior of a kidney: *, supra-renal body; *, kidney; 
, ureter; **, artery and vein. fg. 20, section of a kidney: ’, cortical 
‘substance; *, a Malpighian pyramid, composed of uriniferous tubercles and 
the pyramids of Ferrein, with the papille; *, a calyx; *, pelvis; °, ureter. 
Fig. 21, bladder: *, muscular layer, with its differently arranged fibres; 
“neck of the bladder, with its sphincter muscle; **, ureters; *, suspensory 
ligament from the peritoneum; °, vesicula seminalis; °, prostate gland ; 
’, portion of the urethra. 
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