134 DELLA DRIPS 
and undergo the same changes incident to this phenomenon as the 
others except that, on account of not occupying a position close enough 
to the surface of the ovary, they are not able to discharge their contents. 
Experiment 293-16 (spermophile 328). Captured May 4, 1916. 
Both ovaries were removed May 6, 1916. Weight, 119 grams. 
Gross observations. The fetuses-in the uterus measure about 2 
mm. in length, which makes the luteal bodies in the ovaries older than 
those previously described. 
Microscopic observations of the right ovary. Fixative, formalin 
zenker. Stain, acid fuchsin and methyl green. This ovary contained 
six corpora lutea. These luteal bodies appear differently, due prin- 
cipally to the rapid growth which has been going on among the fibro- 
blasts and endothelial cells. These ovaries suffered some congestion 
through the manipulation of removal, and this helps to show the great 
numbers of capillaries and blood-vessels that have been formed in a 
_short time. The central mass of blood is undergoing rapid organiza- 
tion. No doubt the presence of this blood with its serum and fibrin is 
the great attractive force which aids in the complete formation of the 
luteal body. Fibroblasts and endothelial cells are always attracted by 
serum and fibrin. As soon as the hemorrhage occurs in the follicle, 
they start in to organize it. This is evident from the radial direction 
which the axis of the fibroblasts all take very early. As they go into 
the center, the transformed epithelial cells of the follicle are carried in 
by them. Endothelial cells grow in, and so very early there is formed 
in the corpus luteum a complex system of blood-vessels and capillaries, 
as is seen in sections of this ovary. 
In one of the corpora lutea in this ovary, the hemorrhage was so 
extensive that instead of trying to organize it, the fibroblasts have. 
formed a wall around it. Since the fibroblasts have not penetrated 
very far, there is only a narrow rim of luteal cells. This structure is 
what is ordinarily called a hemorrhagic luteal cyst (fig. 25). Beside 
the corpora lutea in a section of this ovary, one notices readily the large 
clumps of interstitial cells through the medullary portion. These are, 
as a rule, conspicuous in the ovary of early pregnancy. 
Microscopie observations of the left ovary. Fixative, formalin 
zenker. Stain, hematoxylin and eosin. This ovary contains only two 
corpora lutea. There are present in it several large, apparently mature 
follicles. The number of such follicles in an ovary evidently depends 
on the number of corpora lutea. Where there are a good many of the 
latter, the follicles evidently cannot grow. When there are only a few 
corpora lutea in an ovary, one or two follicles may reach the size of 
0.5 mm. x 0.5 mm., or 0.56 mm. x 0.7 mm. These will, of course, 
degenerate as ovulation takes place only once a year, during the rut- 
ting season which has just gone by. And as there are practically no 
large follicles ever seen in the ovaries of July which contain the largest 
luteal bodies, they must degenerate before this time. Perhaps the 
pressure of even one large, growing corpus luteum is enough to bring 
this about. 
