PARTURITION. 



819 



become more mariced. The animal is restless andcontinually agi- 

 tated, and withdraws from the herd, if in the' pasture, in quest of 

 some quiet and remote spot; The mouth of the womb has been 

 gradually opening since the earliest of these signs was manifested. 

 The membranes surrounding: the fetus are the first to extrude. 

 They appear like a bladder, distended as they are with the fetal 

 waters. This fetal fluid, which is secreted by the amnion, is that in 

 which the young embryo floats. The purpose this fluid subserves is 

 assumed by scientists to be to prevent uterine pressure on the fetus. 



Pro. 1082.— Blood-vessels In the Liver of the Equine Fetus. 



and also to keep up an equal temperature in the fetal body, as well 

 as, by lubricating the vaginal passage, to facilitate birth. By the 

 uterine contractions of labor pains, the uterus is shortened and 

 greater pressure is exerted upon the fetus. Short periods of rest 

 follow the paroxysms of pain, which grow frequent and more intense. 

 They are also more prolonged. At length the mouth of the uterus 

 becomes fully dilated, the membranes separate from the inner wall 

 of the uterus, and protrude from the vulva as the "water-bag." The 

 head of the fettfs, preceded by the nose and fore feet, now enters 

 12 



