DECIDUA VERA AND CHORION LMVE OF THE SECOND STAGE. 351 



and chorion are adjacent. Both membranes are quite thin. The decidua is a 

 relatively voluminous membrane containing blood-vessels, v, which for the sake of 

 distinctness have been filled in with black in the drawing. It also contains a 

 series of elongated spaces, which represent sections of the glands. These spaces, 

 gl, are present only in the inferior half of the decidua. Owing to their absence 

 from the superior half, that portion has a more compact structure, and is, there- 

 fore, designated as the compact layer; the lower portion, being broken up and 



c-:,v;K\^v-^^C^!s^^^C^^:-^i^;^^?rt^ ; :V 



%:. ^^'^^^^f^^?^^^^M^^^; 





,^^ ^ ^ 







FIG. 233. HUMAN UTERUS ABOUT SEVEN MONTHS PREGNANT. VERTICAL SECTION OF THE DECIDUA VERA 



WITH THE FETAL MEMBRANES IN SITU. 



Am, Amnion. Cho, Chorion. c, Chorionic epithelium. v, Blood-vessel. gl, Glands. muse, Muscularis. 



X 40 diams. 



made loose in texture by the somewhat numerous gland cavities, is called the 

 cavernous layer, the caverns, of course, corresponding to the gland spaces. The 

 gland spaces are now very much stretched out, a condition which results simply 

 from the general expansion of the uterus during pregnancy. In the gland spaces 

 appear patches of epithelium still intact, and in the cavities themselves isolated 

 cells in various phases of degeneration and disintegration, similar to the phases 

 which may be observed in the decidua vera of one month; but the degeneration is, 

 on the whole, considerably more advanced than in the early stage. Around 



