THE LACTEAL GLAND. 569 



cular fibres. The muscular structure of the uterus may act all at 

 once, or only a part at a time; as during parturition, the os and 

 cervix are at first at rest, while the fund us and body are contract- 

 ing. In convulsions, the whole uterus contracts firmly round the 

 child (KolUker) ; in retention of the placenta, the contraction is con- 

 fined to the fundus. The author is convinced that during the or- 

 gasm a descent of the uterus, an opening of the os, and a dilatation 

 of the canal of the cervix take place. 



The sensibility of the interior of the uterus is very slight ; care- 

 ful sounding of its cavity usually causing no pain, and intra-uterine 

 instruments being worn by many patients m the treatment of ute- 

 rine displacements, with very little inconvenience. The vagina 

 also has but little sensibility internally. The most sensitive parts 

 of the vulva are the clitoris, and the entrance to the vagina at the 

 orifice of the glands of Duverney. 



The mucous secretions from the genital passages of the female 

 have already been specified (p. 198). For the changes undergone 

 by the impregnated ovum during its development in utero, consult 

 the works on Embryology. The original development of the fe- 

 male genital organs very analogous to that of the male organs, 

 during the first part of embryonic life will also be omitted here. 



5. The Lacteal Glands. 



The lacteal glands are of the compound racemose variety, cor- 

 responding in all essential particulars with the parotid and the pan- 

 creas. Each gland consists of 15 to 24 or more flattened lobes ^ to 

 1 inch wide, and which are composed of lobules connected by areolar 

 tissue, containing many fat-celFs. The terminal cseca of the lobules 

 are rounded or pyriform, and 2 J^ to T | T of an inch in diameter. 

 (Figs. 398, and 115.) The smallest ducts leading from these have a 

 simple scaly epithelium; and these uniting, form the larger trunks. 

 Each of the latter running towards the nipple, dilates beneath the 

 areola into an elongated sac, \ to J of an inch wide; 1 then con- 

 tracting to 1 or even J a line, it bends into the nipple, and finally 

 opens at its apex in a separate orifice, g'g to gV of an inch in dia- 

 meter, between the papillae which exist there. (Figs. 306, 307, 308.) 

 These ducts, about 20 in number, are lined by a so-called mucous 

 membrane, longitudinally plicated in the largest, and, deep in the 



1 These reservoirs in the cow hold even a quart. 



