400 JAS. p. HILL. 



empty right uterus shows that it has uudergoue changes 

 parallel with those undergone in the pregnant left, a vascular 

 syncytium of some thickness having been formed all over the 

 surface of the mucosa. 



In this and the following stages I propose to describe 

 separately (1) the changes in the uterus, and (2) the structural 

 features of the foetal membranes and their relations to the 

 uterine wall. 



I. Left Uterus. — The discoidal allantoic placental area is 

 situated on the ant-mesometrial side of the uterus. The 

 uterine surface is thrown into a series of irregularly longi- 

 tudinal folds, this folding being especially marked in the 

 allantoic placental area. One may emphasise this by stating 

 that from edge to edge of the area in a straight line the 

 breadth in its mid region is only about 4 mm., while following 

 the folds the allantoic placental area has a breadth in sections 

 of 13 — 14 mm. 



The muscularis is apparently somewhat thicker than in the 

 preceding stage. 



So far as the corium is concerned no very sharp distinction 

 can be drawn between the portion of it lying beneath the 

 allantoic placental area and that outside the latter. Still for 

 descriptive purposes it is convenient to speak of these two 

 portions separately. 



The corium beneath the allantoic placental area varies very 

 greatly in thickness over its extent owing to the greatly 

 folded nature of the surface. Measured from the bottom of 

 a depression between two folds the corium may have a thick- 

 ness of only '6 mm., while in the region of a fold the thickness 

 may reach as much as 2*7 mm. Outside the allantoic placental 

 area the mucosa is not so markedly folded, and is on the 

 whole thinner. The corium here varies in thickness from 

 "5 to 1*7 mm. This difference in thickness is mainly due to 

 the expansion of the interglandular connective tissue below 

 the allantoic placental area, so that here the corium has a less 

 compact appearance, and the glands are on the whole more 

 widely separated from each other than in the corium outside 



