THE OVARY OF THE SPERMOPHILE 165 
litters of young every year. The atrophy is not completed until 
six or seven weeks after parturition, about the time when the 
lipoid product reaches its crisis of abundance in the cells and 
begins to disappear. Another result which substantiates the 
theory that the lipoid secretion brings about the normal invo- 
lution of the uterus in the very abnormal, even pathologic process 
which goes on in the uterus following the removal of both ovaries 
during all but the more advanced stages of pregnancy. During 
the first half of the period of pregnancy there is no lipoid in the 
corpora lutea, which, according to this theory, would account 
for the pathology in the uterus following double ovariectomy. 
If the ovariectomy is performed late in pregnancy after the 
lipoid droplets have become quite abundant in the luteal cells, 
the animal aborts and the uterus undergoes an involution more 
nearly like the normal, due to the specific effect of the lipoid 
secretion which is already present in the circulation. Mulon 
thought the lipoid of the corpus luteum had an antitoxic action 
toward the poisons elaborated in the development of the fetuses. 
It would seem more reasonable to suppose that it neutralizes 
the toxic products produced in normal involution, which would 
be only a part of its function as a specific agent in effecting 
this normal involution of the uterus. 
It may be added, in closing, that the two luteal secretions are 
undoubtedly emptied into the blood stream in these animals. 
An observation of the elaborate capillary network of these 
structures could lead to no other conclusion. Lymphatic sinuses 
are demonstrable in the corpora lutea, but they are found only 
near the capsule in the proximity of the larger blood-vessels. 
There is no anatomical evidence for concluding that the secre- 
tions are carried away by the lymphatics. 
The writer wishes to express her appreciation for the valuable 
aid given her by Dr. Frank C. Mann, head of the Division of 
Experimental Surgery and Pathology of the Mayo Clinic, under 
whose direction this work was done. 
