THE OVARY OF THE SPERMOPHILE 153 
Gross observations. The uterus appears healthy, a normal pale 
pink color, but it is very much swollen (table). There are three small 
palpable swellings i in the left horn LS only from the increased 
size of the uterus at these points. Placental sites in the right horn 
not definitely established. Evidently the animal had aborted. The 
cause of the swollen condition of the uterus is not evident. 
Microscopic observations of the ovaries. Left ovary: fixative, 
formalin zenker; stain, hematoxylin and eosin. Rfght ovary: fixative, 
formalin zenker; stain, hematoxylin and eosin. The left ovary re- 
moved at operation May 8, 1916, is normal. It contains eight corpora 
lutea, 0.8 mm. x 0.9 mm. in size. The right ovary obtained at au- 
topsy May 20, 1916, is very interesting. It contains only one corpus 
luteum, 0.4 mm. x 0.5 mm. in size. This is in the final stage of its 
life cycle, the degenerative stage described in the first part of this 
work. The rest of the ovary is normal. Through its cortex are eight 
large follicles, apparently mature, not showing any atretic changes. 
One of these measures 0.8 mm. x 0.6 mm. There are many smaller 
growing follicles also, and quite a number of primordial ova. Almost 
in the middle of the ovary, just inside the cortex, is the one degenerated 
corpus luteum. It is full of large fatty degeneratiye vacuoles and 
enlarged blood-vessels and capillaries. The connective tissue has made 
great inroads. What made this corpus luteum degenerate is not evi- 
dent. It will be shown later that after the removal of one ovary the 
other showsno pathologic effects. Andevenafter removal of one ovary 
and a uterus containing fetuses, the other ovary with its corpora lutea 
shows no pathology. Evidently the ligation of the tube caused the 
corpus luteum in the right ovary to degenerate and abortion occurred, 
the same as on removal of both ovaries. This would make it appear as 
if the corpus luteum was the part of the ovary necessary to the develop- 
ment of the fetuses. 
Discussion and summary of results. Ten animals were operated 
on to get results from the removal of both ovaries containing 
corpora lutea on the uterus containing fetuses. One of the 
animals died from too much ether. The others lived, but none 
of them came to term. Those operated on early in pregnancy 
did not abort. The placentas and fetuses degenerated. Those 
operated on when the pregnancy was well advanced, aborted. 
That this was not the effect of operative trauma will be shown by 
another series of experiments on the removal of one ovary in 
pregnant spermophiles. 
