126 



ANATOMY AND PHTSIOLOGY OF 



the full or empty condition of the bladder. 

 The largest part of the canal is the poste- 

 rior ; there it exceeds the dimensions of the 

 bladder. 



The length of the canal is about eighteen 

 inches. Its course is horizontal, and rather 

 shows an inclination to the curve of the 

 rectum. 



The vagina, at its commencement from 

 the vulva, is much thicker in its walls than 

 elsewhere ; in composition it is partly mus- 

 cular and partly membranous. The orifice 

 of it is clothed in that strong, red, circular, 

 fleshy band, which forms the sphincter 

 vagina ; and the adjoining part of the canal 

 is also encircled by some considerable fleshy 

 covering, and thickly coated with muscular 

 fibres. Farther forward than this the vagina 

 is composed of membrane. 



The JSIembrane of the Vagina. — The part 

 of which it is constituted is one of the 

 mucus class, and one that possesses consid- 

 erable density, extensibility, and resistance. 

 Its exterior surface is rough. Its interior 

 is smooth, and has a pale pinkish cast; 

 unless the mare be under the venereal oes- 

 trum, and then its redness is heightened, 

 and its secretion augmented. In the ordin- 

 ary state, this membrane is thrown into 

 folds, larger in breeding mares than in others, 

 technically called rugae. 



Considerably in advance of the clitoris is 

 an opening leading from the lower part of 

 the canal, large enough to admit with ease 

 any one of the fingers : this is the orifice of 

 the meatus urinarius, or outlet of the blad- 

 der: it is guarded by a doubling of the 

 vaginal membrane, which hangs over it, and 

 serves the purpose of a valve. 



The large and conspicuous protuberance 

 at the bottom of the vagina, is the mouth 

 of the uterus. 



The uterus, or womb, is a hollow mus- 

 culo-membranous organ, united to the ante- 

 rior part of the vagina, and is destined for 

 the reception of the foetus. We distinguish 

 the uterus by the body, horns, neck, and 

 mouth. The body is the oblong or cylin- 

 drical part, growing out of the anterior por- 

 tion of the vagina, in the centre of which 



it is terminated internally by the os-uteri, 

 or mouth of the womb ; it gives origin, in 

 front, to the horns. This part lies wholly 

 within the pelvis, between the bladder and 

 rectum, and is entirely covered by peri- 

 toneum. 



The cornua, or horns, rise from the body 

 of the uterus, and diverge towards the loins. 

 Their length and size will be much greater 

 in breeding marcs than in others. In figure 

 they are cylindrical ; they bend upward in 

 their course, and terminate in round extrem- 

 ities, to which are loosely appended the 

 ovaries, or testicles, through the medium of 

 the Fallopian fubes. 



The cervix, or neck, of the uterus is the 

 rugose portion, protruded backward into the 

 cavity of the vagina, which has a flower- 

 like appearance, and can only be seen in a 

 virgin uterus in the undistended state ; dur- 

 ing gestation it undergoes a remarkable 

 change. 



Independently of its union with the 

 vagina, the uterus is confined in its place 

 by two broad portions of peritoneum, 

 which attach it to the sides of the pelvis, 

 named the lateral ligaments of the uterus. 

 During the period of gestation, the uterus 

 experiences considerable extension. The 

 Fallopian tubes are two trumpet-shaped 

 canals, having a remarkable serpentine 

 course ; running within the folds of the 

 iigamenta lata, from the extremities of the 

 horns to the ovaries. 



The tube commences by an aperture in 

 the cornu, having an elevated whitish mar- 

 gin, which is scarcely large enough to admit 

 a small silver probe : from this it proceeds 

 forw^ard, folded in peritoneum, and ex- 

 tremely convoluted, until it reaches the 

 ovary, to which it becomes attached; it 

 then begins to enlarge in its diameter, 

 grows less convoluted, and serpentines along 

 the lower side of the ovary ; it afterwards 

 ends in a fringed doubling of membrane. 



The internal membrane of the tubes is 

 similar to that of the uterus. 



The ovari, or female testicles, are two 

 egg-shaped bodies, situated farther forward 

 than the Fallopian tubes, within the cavity 



