siGXS Axn corns E of r.i/rrrniT/o.v. 235 



delayed ; indeed, in some cases it may be useful, as when the uterus is 

 over-distended with fluid — in hydramnios, for example — wlien its dis- 

 charj^e allows the or^an to contract more freely. In other instances the 

 membranes are remarkably strong and resisting', and withstand the con- 

 tractions for a long time after they have been extruded beyond the vulva ; 

 their artificial rupture may even be required. Sometimes they do not 

 rupture at all, and the fcttus is born in them, or even after them, as has 

 occurred in the Cow. The rupture usually occurs at the most dependent 

 part of the bag — at the uterine orifice, towards the os, or in front of it. 

 Then succeeds a brief interval of (juiet— the foetus being meanwhile 

 retained in the uterus — during which the organ is closely applied to the 

 body of the fii-tus. and is preparing itself for a final effort, which is soon 

 made. The contractions are most energetic and rapid, and every time 

 they are made the waters flow in small quantity, moistening and relax- 

 ing the parts ; the fcrtus passes on until the fore feet and muzzle, form- 

 ing a kind of cone, appear at the vulva, the orifice of which is opened 

 by them. When the head has cleared the vulva, there is usually a 

 short pause, as if to allow the tissues of this region to become accus- 

 tomed to the distention, and to prepare them for the still greater strain 

 which is yet to be imposed on them. The thorax and shoulders of the 

 fietus have now arrived at the inlet of the pelvis, and as they form the 

 deepest and most diflicult part of the young creature's body, the con- 

 tractions which ensue for its complete expulsion, though most powerful 

 and continuous, only impel it slowly towards the outlet, on arriving at 

 which a more energetic and painful effort than all the others pushes it 

 through. The act may now be said to have terminated ; as to expel 

 the croup requires only a few comparatively weak throes, and the weight 

 of the anterior part of the body of the foetus, hanging beyond the vulva, 

 greatly aids them. It is rare indeed that the croup offers a serious 

 obstacle to expulsion. 



During this act the creature betrays evidence of pain, especially if it 

 be a primipara : and this is particularly marked when the head of the 

 f(rtus passes through the, as yet, incompletely dilated os, and still more 

 so when the chest and shoulders strain the textures of the vulva and 

 perinipum to the utmost. Then the pulse is hard and frequent, and the 

 skin hot — sometimes covered with perspiration — or the body is rigid. 

 The Hitch and Cat often utter a cry of pain as the head and chest pass 

 through the vulva. 



After the young animal is expelled, the umbilical cord is torn, and 

 the liquor amnii remaining in the uterus escapes, accompanied or 

 followed by a little blood resulting from the sudden separation of the 

 placenta?. 



The position assumed by animals during parturition is somewhat 

 variable. The larger animals which usually only bring forth one at a 

 birth, such as the Mare, Cow, and Sheep, ordinarily do so standing ; 

 and this position has the following advantage : The vertebro- sacral 

 angle is ettaced, and the obstacle that its projection might offer to the 

 passage of the foetus into the pelvis is diminished ; the auxiliary 

 muscles — abdorninal and diaphragmatic — can act more energetically ; 

 the young creature, being sustained by the umbilical cord when it has 

 cleared the vulva, glides gently on the half-flexed hocks of the parent, 

 and so reaches the ground without injury (Fig. (39). 



Such an attitude, however, is far from being constant with these 



