34 ; VETERINARY OBSTETRICS. 
fluid is secreted called the “liquor amnii,” or “amniotic 
fluid,” in which the foetus floats in the later period of 
pregnancy. This fluid assists in regulating the 
temperature of the foetus, also, by diffusing shock, 
prevents injury from external violence. It also assists 
CHORION OF THE MARE AT MID-TERM (INFLATED). 
A, Posterior portion occupying the Body of the Uterus; B, Left Cornu 
plicated and sacculated; C, Right Cornu, longer than the left, and con- 
taining 2 portion of the Fcetus. 
in the act of parturition by dilating the passage, or 
cavity, and when the sac is ruptured the fluid assists in 
the lubrication of the vagina and vulva. 
The Allantois. 
This allantoid membrane is composed of two 
contiguous layers: a superficial one, which is applied 
to the inner aspect of the chorion ; and an internal or 
deep layer, which is applied to the external aspect of 
the amnion. These two layers come together at the 
umbilical opening to form a constricted hollow passage 
or tube. This constricted portion passes into the 
