430 THE HUMAN SPECIES 



slowly developed, is connected with the upright position and does 

 not occur in animals ; nor do anteversion, due to a pendulous 

 abdomen, or the oblique position of the pregnant uterus. As 

 against these purely human abnormalities we may set others 

 which are peculiar to animals. Twisting of the uterus round 

 its long axis due to the pull on the broad ligaments exerted by 

 the growth of the foetus in utero, occurs in cows, and less fre- 

 quently in sheep and goats, while it is still less common in 

 horses, swine and dogs. In other cases a hernia of the uterus 

 may occur after rupture of the abdominal muscles, so that the 

 pregnant uterus lies in a sack formed solely of the integument. 

 In bitches hernia of the uterus into the inguinal canal may 

 occur. Prolapse and procidentia of the pregnant uterus may 

 occur in both human beings and animals ; the latter condition 

 is frequently associated with prolapse of the vagina. In the 

 human female prolapse and procidentia commonly occur only 

 during the first three months, but in these they are apparently 

 fairly common. Prolapse of the vagina only occurs in multi- 

 parse. From the fourth month onward this untoward event, 

 which is frequently the cause of abortion, becomes less and less 

 common. Among domestic animals, cows, mares and goats 

 are especially liable to prolapse of the vagina. Lesions of the 

 foetus due to external mechanical influences during pregnancy 

 occur, though not frequently, both in human beings and animals. 



Haemorrhages caused by the presence of innocent or malig- 

 nant growths are also common to both during this period. Such 

 haemorrhages are also due in domestic animals, as mares 

 and cows, to apoplexy of the chorionic villi, or to a kind of 

 placenta prasvia, when the network of villi belonging to the so- 

 called Chorion l&ve is implanted in the region of the internal 

 os as an accessory placenta. 



A single, complete, central or lateral placenta praevia is 

 peculiar to the human species, and is connected with the erect 

 position. 



With regard to dropsy of the fcetal membranes, caused by 

 general fcetal oedema in cases of circulatory and renal disease, 

 a difference is to be noted between human beings and animals. 

 In human beings in whom the allantois disappears early, dropsy 

 can only occur in the amnion, while the early obliteration 



