350 MINOT. [Vot. II. 
lani’s suggestion correct that the decidual cells arise from the 
blood-vessels. The contents of the blood-vessels are blood cor- 
puscles and coagulum ; the blood corpuscles resemble the ordi- 
nary red globules of the rabbit, a point deserving notice in view 
of the change occurring later. There are occasional leucocytes, 
but they are nowhere numerous. 
The two layers of the vascular zone are now distinguishable 
not only by the size of the vessels (not well illustrated in the 
section drawn as Fig. 2), but also by the much greater develop- 
ment of the perivascular cells in the outer zone; in the sub- 
glandular zone the cells are now not far from their maximum 
development, forming a coat one or two cells thick around the 
vessels ; on the outer zone, on the contrary, the number of lay- 
ers of cells has still to increase very much; consequently as 
development progresses, the difference between the subglandu- 
lar and outer zone becomes more conspicuous. 
The epithelium and glands repay careful study at this stage. 
The degenerative processes are similar in certain essential re- 
spects in all parts of the uterine swelling. The likeness con- 
cerns five chief points: 1°, the deep portions of the glands 
show little change in the epithelium; 2°, the upper portions are 
very far degenerated; 3°, the protoplasm of the degenerated 
epithelial cells is fused into a continuous thick hyaline mass, the 
growth of which ultimately obliterates the cavity of the glands ; 
4°, the nuclei of the degenerated epithelium multiply enor- 
mously; 5°, the degenerated tissue is absorbed by progressive 
vacuolization. 
But although these resemblances are dominant, each of the 
three principal regions, the placental, peri-placental, and ob-pla- 
cental, presents now a very distinctive appearance, and has its 
distinctive further history. 
In the peri-placental region, with which we begin, because the 
relations are more obvious there than elsewhere, we find the 
appearances shown in Fig. 4. The line of demarcation from 
the placenta, though not definite or sharp, can be approximately 
determined, but the passage into the ob-placental region is very 
gradual. The most striking feature of the section is the de- 
generated and enormously thickened epithelium, /.¢, deeply 
tinctured by the eosine, and remarkable for the crowded band 
of nuclei. Within the area of the degeneration the former 
