298 HISTOLOGY. 



pregnancy. Often they produce macroscopic retention cysts, due to the 

 accumulation of secretion [ovules of Naboth, named for the Leipzig 

 anatomist who mistook their nature in 1707]. When empty of secretion 

 the cervical glands are said to resemble the uterine glands. Toward the 

 external orifice of the uterus the epithelium becomes stratified, resting on 

 papillae and having its outer cells squamous. Such epithelium is found 

 in the vagina, and after the first child-birth it may extend into the lower 

 half of the cervix. 



The tunica propria of the uterus is a very vascular reticular tissue 

 with abundant nuclei. It contains many free lymphocytes and its lym- 

 phatic vessels form a wide meshed network with blind extensions. They 

 empty into a network of larger vessels in the subserous tissue. Medul- 

 lated nerves are said to extend to the epithelium and many non-medul- 

 lated fibers supply the muscularis. Ganglion cells detected within the 

 uterus by the Golgi method are believed to be not more ganglionic than 

 those of the intestinal villi found by the same method. In the utero-vagi- 

 nal plexus which is the source of the sympathetic nerves of the uterus, 

 ganglion cells have been found in the vicinity of the cervix. 



MENSTRUATION. 



Menstruation is the periodic degeneration and removal of the super- 

 ficial part of the mucosa of the uterus, accompanied by haemorrhage 

 from the vessels of the tunica propria. For four or five days before the 

 discharge occurs, the thickness of the mucosa increases due to the conges- 

 tion of its vessels and the proliferation of the reticular tissue. The glands 

 become wider, longer, and more tortuous, opening between irregular 

 swellings of the superficial epithelium. Red corpuscles pass out between 

 the endothelial cells of the distended vessels and form subepithelial masses. 

 This stage of tumefaction is followed by one of haemorrhage and des- 

 quamation lasting about four days. The epithelium of the surface and 

 outermost parts of the glands becomes reduced to granular debris, or it 

 may be detached in shreds. The underlying vessels rupture and add to 

 the blood which had escaped by diapedesis. In the stage of regeneration 

 which requires about seven days, the epithelium spreads from the glands 

 over the exposed reticular tissue, the congestion diminishes, and the 

 mucosa returns to its resting condition. In about twelve days the cycle 

 begins anew. The cervix takes no part in menstruation except that the 

 secretion of its glands may increase during the stage of congestion. 



Beginning at puberty (12-15 years) menstruation takes place normally 

 once in 28 days for 33 years, more or less. During pregnancy it is interrupted, 

 although the time when it should occur may be indicated by slight uterine con- 



