578 



GENERATION. 



[CHAP. XL. 



Fig. 273. 



brane is due. In the mucous membrane of the uterus of the bitch, 

 Dr. Sharpey has described two distinct kinds of glands, one simple 

 and the other compound. The openings of both these forms of 

 glands may be readily seen upon the surface of the mucous mem- 

 brane ; and they soon increase in dimensions, in order to receive the 

 foetal processes of the chorion, which are covered with epithelium, 

 similar to that lining the follicle. Immediately before the large 

 compound glands open upon the surface, Dr. Sharpey describes 

 their tube as forming a dilatation or cell, into which a foetal 

 process of the chorion is received. At the bottom of this cell the 



duct may be seen ; and as it passes to- 

 wards the deep surface, it is observed 

 to form the branched compound gland. 

 At parturition, the vessels of course come 

 away with the decidual membrane, as 

 well as the cells just referred to, but the 

 ducts and branching terminations of the 

 glands remain behind. From this ar- 

 rangement it follows that, in the bitch, 

 the secretion elaborated from the system 



Uterine glands of the bitch. Twelve .. ,, , ,, *, 



diameters, i. simple glands. 2. Com- oi the mother by the agency oi these 



pound glands. After Dr. Sharpey. , n . , _. . .,1 



glands is brought into close contact with 

 the vessels of the foetus, and afterwards absorbed by them. 



In the human decidua, the openings of the glands 

 may be distinctly seen, and their epithelial lining 

 readily traced. The tubes can be followed through 

 the membrane; in fact, from numerous observa- 

 tions, there can be no doubt that, like the decidual 

 membrane in the bitch, the human decidua consists 

 really of the altered mucous membrane of the uterus. 

 Leydig has seen ciliary motion in the uterine 

 glands of the sow. 



Next we have to consider how it is, that the 

 ovum becomes covered with the decidual mem- 

 brane. Dr. W. Hunter looked upon the decidua 

 ^weiJe^dia- as a closed sac, separating the uterine cavity from 

 ' Tube Wit 2 h the openings of the Fallopian tubes. When the 

 ovum descended, he supposed that it pushed the 

 decidua, as it were, before it, and thus became 

 covered, in the same manner that the viscera are invested with peri- 

 toneum ; and hence, Dr. Hunter termed that portion of decidua 

 covering the ovum, decidua reflexa, while that lining the uterus was 



Fig. 274. 



Thin section of human 

 decidua soon after im- 



,fter Dr. Sharpey. 



