TEE GENITAL ORGANS OF THE FEMALE. 999 



and pass to the abdominal subcutaneous vein ; capillaries form a rich network 

 around the alveoli. The lymphatics are very developed. (The nerves are 

 derived from the first lumbar pair.) 



Functions. — The mammte secrete the milk ; they undergo remarkable 

 modifications at puberty and at the end of each gestation — modifications which 

 are related not only to their volume and secretion, but also to their minute 

 structure. After gestation, the gland-vesicles shrink — become, as it were, 

 atrophied, and have only a polygonal epithelium. At the termination of gesta- 

 tion, they are enlarged, new vesicles are developed, and the epithelium changes 

 its character — filling the gland cavities, 



assuming a spherical shape, and becoming Fig. 539. 



charged with fat-granules. The period of .. fvo°o^°''°9<' 



lactation being completed, the mamms - '- - ^ - ^ ^ 



assume their former character. (In Mares 

 which have not been bred from, the 

 mammte are hard and small, the teats only 



slightly prominent, and the glandular _oo„^-„ 6„ ^ 



tissue scanty. In old brood-mares, on the 0°° o, ®g^ Opo°o 0°^° o o p» o°Oo*o °?°°. © 



contrary, they are flaccid and pendent, and ^ ^5 ^o o ^j^ ^ 0-0 ^ 

 the teats somewhat lengthened. The milk "^% 0° °|o ^ o ®0°^. 

 secreted by the mammary glands is a white ''g'>°°so° °So 00°^" 



fluid, possessing a sweet taste, and com- . ''W0'$^°o'^ ^ ■ 



posed of an albuminous water containing ^^^''P°!6Bp° 



caseine in solution, milk sugar, salts, and 



fatty matter in globules — the butter. 



TTsnallv a small nnantitv i<5 '^pfrptprl snmp microscopical appearance of milk, with 



usual y a small quantity is secreted some ^^^ intermixture of colostric corpus- 



days before parturition ; that which is cles at a, a, and elsewhere. 



yielded for a short time after that period 



— the colostrum — is rich in white corpuscles, and has purgative properties. The 



colostrum is of a rich yellow colour, less fluid than the milk of a later period, 



of a higher specific gravity, sUghtly acid, and containing large oil-globules, a few 



irregular flakes — probably epithelium-scales — a little granular curd-like matter, 



and a small number of granular corpuscles.) 



Differential Characters in the Female Genital Organs of the other Animals. 



Certain organs offer some differences worthy of notice, while others are formed as in 

 Solipeds. 



Ruminants. — Ovaries. — In the Cow, the ovaries are relatively much smaller than in the 

 Mare, but tlieir form and structure are identical. (The Graafian vesicles are visible through 

 the tunica albuginea.) 



Uterus. — The uterus of the Co"w, compared with that of the Mare, offers but few differ- 

 ences with regard to its general disposition in the pelvic and abdominal cavities, except that 

 it is not so advanced in the latter. Supposing the uterus to be perfectly horizontal, a trans- 

 verse line drawn through the plane of the abdomen, before the external angle of the ilium, is 

 exceeded by the extremity of the cornua from about 1 J to 2 inches ; so that if the animal were 

 on its back, the uterus would only be prolonged to the fourth or fifth lumbar vertebra. 



With regard to form, the uterus of the Cow presents a very remarkable disposition, which 

 it is necessary to note. The concave curvature of the cornua looks downwards, while in the 

 Mare it looks upwards ; though in both the sublumbar ligaments are attached to this con- 

 cavity. Therefore it is that in the Cow — if we consider the uterus as freely suspended in the 

 abdomen — the extremity of tht) cornua is twisted outwards and upwards, while the base, 

 although drawn in the same direction by these ligaments, maintains its direction, because it 

 is in a manner fixed by the body of the uterus. The latter receives, like the cornua, the 



