THE OVARY OF THE SPERMOPHILE 129 
Experiment 379-15 (spermophile 200). Captured during the spring 
of 1915. The ovaries were removed surgically September 14, 1915. 
Weight, 150 grams. 
Microscopic observations of an ovary. Fixative, formalin zenker. 
Stain, hematoxylin and eosin (fig. 10). There are nine good-sized 
follicles, the larger of which measure about 0.4 x 0.4 mm. There are 
twice as many follicles half as large. There is a goodly number of 
small hyalinized follicles. Around the periphery of the ovary are 
numbers of primordial ova. The larger follicles are approaching 
maturity, but are still growing. They contain many mitotic figures 
and very little liquor folliculi. They are located through the cortex 
of the ovary, only three being near the surface. None of these larger 
follicles appear to be atretic. Through the medullary portion of the 
ovary are conspicuous clumps of interstitial cells. 
The spermophiles begin to become torpid about September 15, but 
they are active by spells for some time after this, depending on weather 
conditions. In the laboratory, some are active until November 15. 
Experiment 503-15 (spermophile 254). Captured during the spring 
of 1915. Sacrificed November 15, 1915. The animal had been hiber- 
nating six days. 
Microscopic observations of an ovary. Fixative, formalin zenker. 
Stain, hematoxylin and eosin. This ovary appears very similar to 
that of spermophile 200. The larger follicles are about the same in 
number, size, and location. There are about the same number of 
smaller and hyalinized follicles as well as primordial ova. The size 
of the ovaries as a whole, however, has decreased. This is probably 
due to a marked decrease in the size of the blood-vessels and sinuses. 
The clumps of interstitial cells are much less conspicuous. The 
ovaries appear to have prepared themselves for their long period of 
functional inactivity. 
Experiment 246-16 (spermophile 291). Captured April 25, 1916. 
Was injured in being caught, so was sacrificed immediately. Weight, 
170 grams. 
Gross observations of the uterus. The animal is in rut. The 
rutting season evidently lasts about two weeks. During this time 
practically all the females become impregnated. It may be stated 
here that the laboratory animals come out of hibernation much earlier. 
Those killed from the 1st to the 15th of March appeared to be in rut 
and one killed April 11 was found to be pregnant, showing that weather 
conditions set the time of the commencement of their sexual activities. 
The large size of the uterus is immediately noted (fig. 7). There has 
been an increase in length and breadth. It is twice as large as the 
inactive uterus. The cervix shows the greatest increase in size and it 
is filled with a thick mucoid substance. The walls of the vagina are 
swollen. It is very evident that the great increase in the size of the 
whole organ is due to a marked increase in the fluid content, which 
gives it a pale appearance. (For measurements see table.) 
