THE OVARY OF THE SPERMOPHILE Wea 
ovarian cycle in the spermophile with a view to gaining some 
accurate information of the origin, development, life history, 
and function of the corpora lutea of the ovary. 
In the spring of i915, numbers of spermophiles were captured. 
But not having realized how very soon the animals become im- 
pregnated after coming out of hibernation, no strenuous efforts 
were made to obtain them until they were quite numerous in 
the fields, and consequently they were found to be either in 
advanced stages of pregnancy or lactating. However, all the 
animals that could be gotten were used for a study of the ovarian 
cycle through the summer and fall, until hibernation began. 
Several animals were sacrificed each week. They were killed 
quickly with ether and bleeding. The ovaries were immediately 
placed in one of several fixatives, 10 per cent formalin, Zenker’s 
fluid with acetic acid, Bensley’s formalin Zenker, and Bensley’s 
acetic acid bichromate. Many stains were experimented with. 
After considerable study of the fixed and stained sections, it was 
decided that for the problem in hand, two fixatives seemed 
best, Bensley’s formalin Zenker and Bensley’s acetic osmic 
bichromate—the former particularly for the nuclear structures 
and the latter for the elements in the protoplasm. In all the 
work of the past spring (’16), one ovary of each animal sacrificed 
was routinely placed in formalin Zenker and the other in acetic 
osmic bichromate. 
Of the sections fixed in zenker, the best results were obtained 
with a modified Weigert stain (copper-chrome-hematoxylin), 
Ehrlich’s hematoxylin and eosin, Mallory’s connective-tissue 
stain, and Bensley’s acid fuchsin and methyl green. A few 
sections of each series were prepared with these stains. 
Of the sections fixed in acetic osmic bichromate, one of each 
series was stained with the Weigart stain and several with the 
acid fuchsin and methyl ‘green of Bensley. Complete paraffin 
serial sections were made of all the ovaries studied. 
The spermophiles went into hibernation about the middle of 
October although many of them became partially torpid earlier 
than this. The next spring it was determined to get them early 
enough. The frost was not out of the ground until about 
THE AMERICAN JOURNAL OF ANATOMY, VOL. 25, Nu. 2 
