160 
large mature follicles are present. 
in the left ovary. 
mm. x 0.7 mm. or 0.7 mm. x 0.7 mm. 
DELLA DRIPS 
There are six corpora lutea present 
They are of a very early stage, and measure 0.6 
The cells are full of granules. 
There is a core of blood in the center which is undergoing organization. 
It certainly appears as if ovulation had taken place shortly before the 
animal was sacrificed. 
Comparative sizes of uteri 
LENGTH | LENGTH SIZE OF WIDTH WIDTH 
EXPERI- | SPERMO- DATE OF OF BODY SIZE OF OF OF 
MENT PHILE RIGHT LEFT OF CERVIX RIGHT LEFT 
HORN HORN UTERUS HORN HORN 
cm. cm. mm. mm. mm. mm. 
20(-15 | 139 | April 22, 1916 AS 4.5. | 92a |) 2206") ama eaten 
42’-15 | 232 | May 8, 1916 5.6 | 5.6 | 4.0 | 1.8 4) O:75)\euee 
42°-15 | 233 | May 9, 1916 7.0 | 6.5. | 8.0 9) 430) |) e0/a ieee 
437-15 | 242 | May 9, 1916 6.3: | 6.3.) BION e250) soca anon 
246-16 | 291 | April 25, 1916 12.4 || 10:31, 2895 1 Sy 0.) . Aa Oana 
2°€-16 | 298 | April 29, 1916 7.2 VO 704) 900. |) sO. |) oe0nr aoe 
354-16 | 374 | October 20,1916| 6.8 | 6.0 | 35 | 2.0 | 1.0) a0 
35-16 | 378 | October 30, 1916 | 6.3 | 6.3 | 45 | 26 | 1.0 eee 
657-16 | 462 | October 30,1916] 6.7 | 6.5 | 5.5 | 2.0 | 1.5 | 1.5 
30-16 | 344 | May 20, 1916 6.8.9) 7.2 WeSs0). 18:0) 7) eos ae 
SUMMARY AND DISCUSSION 
The results obtained from the histologic and experimental 
investigations carried on may be summarized as follows: 
1. In the spermophiles, ovulation occurs only once a year, 
during the rutting season in the early spring. Ovulation is 
dependent on the stimulus of coitus, for no corpora lutea were 
found in the ovaries of animals which were kept from the males. 
2. The corpora lutea cannot be responsible for the phenomena 
of rut for they are not present in the ovaries at this time. 
3. The corpora lutea develop and pass through their normal 
cycle after ovulation whether fertilization follows or not (foot- 
note 2, p. 159). 
4. While the corpora lutea are present in the ovaries, especially 
during the two months following parturition, the process of 
developing and ripening the follicles is at a standstill. 
5. If the uterus is removed after conception, the corpora lutea 
do not begin to degenerate, but pass through their normal cycle. 
No effects are noted in the ovaries. 
