138 DELLA DRIPS 
the latter structures begin to increase in size quite rapidly about the 
time of parturition, there seems to be a degeneration of all the mature 
follicles even where there are only one or two luteal structures present. 
There are five medium-sized and about twenty small growing normal 
follicles, only a few of which show atretic changes. The primordial 
ova are very few in number, and the interstitial cells can scarcely be 
distinguished from the connective-tissue cells of the stroma. 
Experiment 368-16 (spermophile 387). Captured May 24, 1916. 
Sacrificed May 25, 1916, twelve hours after having given birth to 
young. Weight, 115 grams. 
Microscopie observations of the left ovary. Fixative, acetic osmic 
bichromate. Stain, acid fuchsin and methyl green. The three luteal 
structures in the left ovary of the animal measure either 0.9 mm. x 
1.1 cm. or 0.9 mm. x 1 em. The appearance of the luteal structure 
as a whole and of the individual cells is very similar to that of sper- 
mophile 383. 
Experiment 369-16 (spermophile 388). Captured May 24, 1916, and 
sacrificed May 26, 1916, twenty-four hours after having given birth 
to young. Weight, 115 grams. 
Microscopic observations of the left ovary. Fixative, acetic osmic 
bichromate. Stain, acid fuchsin and methyl green. The corpora lutea 
of the ovaries of this animal measure 0.8 mm. x 0.9 mm. There is 
scarcely any new noticeable difference unless it is a slight increase in 
the number of lipoid droplets. 
Experiment 370-16 (spermophile 389). Captured May 24, 1916. 
It gave birth to young on May 25, 1916. It was with the young until 
May 26, 1916, when it killed them. The next day, May 27, 1916, the 
animal was sacrificed. Weight, 135 grams. 
Microscopic observations of the left ovary. Fixative, acetic osmic 
bichromate. Stain, acid fuchsin and methyl green. The corpora 
lutea in this ovary show a marked increase in the amount of lipoid in 
the luteal cells. The red granules have correspondingly decreased in 
number. There are no other differences except a slight increase in 
size of the luteal structure and the cells. 
Experiment 372-16 (spermophile 391). Captured May 18, 1916,and 
gave birth to normal young May 22, 1916. The young were destroyed 
May 26, and the animal was sacrificed May 31, 1916. 
Microscopic observations of the left ovary. Fixative, acetic osmic 
bichromate. Stain, acid fuchsin and methyl green. The corpora lutea 
in the ovaries show the lipoid content to be still more increased in 
amount and the red granules to be very scarce. There are no other 
differences. It might be stated here that there is some variation in 
the time when this lipoid change comes on. For instance, the corpora 
lutea of the ovaries of spermophile 390, ten days after parturition, do 
not contain as much lipoid as those of spermophile 391, nine days after 
parturition. But the majority of luteal bodies for any given time 
before or after parturition appear very similar. 
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