466 ORREN LLOYD-JONES AND F. A. HAYS 
gether. When this behavior developed such females were dis- 
carded and replaced by newly operated stock. Post-mortem 
examinations of some of the discarded females showed no easily 
apparent changes in their reproductive organs to account for 
their changed behavior toward the males. Many of them had 
become very fat and rather sluggish. Altogether about twenty- 
five females were operated upon. About an equal number of 
females were used for ‘end matings.’ 
RECOVERY OF SEMEN 
There are several methods which have been used by investi- 
gators and others for securing specimens of mammalian semen. 
Ivanoff (’07) recommends highly the vaginal sponge, and advo- 
cates the same for use in the horse, the cow, and the sheep. 
An attempt was made to adapt this method to the rabbit by 
packing the vagina with absorbent cotton. ‘The method was 
not successful. The size of the piece of sponge which can be 
placed deep in the vagina is too small to absorb and yield up 
sufficient semen on which to work, and if larger pieces are used 
they remain too near the exterior and prevent penetration by 
the male. The condom (breeding bag of stallion grooms) has 
been used much by horse breeders when practicing artificial 
insemination of females. Good membranes of this sort were 
prepared from the caeca of chickens, but it was found impossible 
to use them on the males; neither could they be held in position 
as a ‘false lining’ of the vagina at the time of coition. Detlefsen 
(14) successfully secured for examination specimens of semen 
from many different males by making a slight incision in the epi- 
didymis and expressing a few drops of its contents. This method 
will not answer when, as in the present case, a large number of 
specimens must be taken from a single male. In the case of the 
rabbit, ejaculation cannot be induced by artificial stimulation. 
The method finally adopted and used in all cases was the old 
and simple one—recovery by catheter. A small-diameter rub- 
ber catheter moistened in a saline solution was introduced for a 
distance of about 16 to 20 em., thus penetrating as far as the os. 
