PHYSIOLOGY OF PARTURITION. 225 



above the other did not check this escape, and it was necessary to fix a 

 compress, steeped in perchloride of iron, along the course of the cord 

 before the haemorrhage could be checked. It must be borne in mind 

 that similar accidents are possible, if a ligature is not applied an inch or 

 so from the umbilicus. Whether it be tied or not, the portion remaining 

 attached to the umbilicus soon becomes dry and withered, and falls off 

 in a few days after birth ; the other end most frequently hanging to the 

 fcetal membranes, which immediately after parturition protrude from the 

 vagina. 



4. Expulsion of the Membranes. — The expulsion of the fcetal membranes, 

 or "afterbirth," as they are sometimes designated, may occur at birth, 

 immediately after, or be delayed for a variable period : this depending 

 not only upon accidental circumstances and individual peculiarities, but 

 also upon species, and, consequently, the placental connections. 



Immediately after the foetus is expelled, the uterus contracts energeti- 

 cally on itself, and its internal capacity rapidly diminishes ; consequently, 

 the placental villosities are detached from their alveoli, the uterine and 

 chorionic surfaces become wider apart, and the placenta is ultimately 

 separated from the uterus. The same contractions which loosened them, 

 are also instrumental in forcing the membranes through the gaping flaccid 

 OS into the vagina ; and the auxiliary muscles, being again stimulated by 

 their presence here, as they were by the head of the foetus in the same 

 passage, add their powerful contractions ; so that these new pains, aided 

 by the physical weight of the extruded portion with its appended umbili- 

 cal cord, soon bring the whole mass away. The contractions of the 

 vagina have probably little, if any thing, to do with this expulsion, which 

 is rarely followed by hemorrhage in animals; though in woman, oVvingto 

 the inertia of the uterus, this accident is not at all uncommon. Some- 

 times the expulsion of the membranes is expedited by the young creature, 

 as it descends from the vulva. 



With the Mare, owing to the disseminated placenta and the slight 

 adherence of the placental villi, the separation of the membranes takes 

 place rapidly ; indeed, the foal is not unfrequently born in the intact, 

 envelopes. But generally only a few minutes elapse before the afterbirth 

 is detached. Retention of the placenta is therefore exceedingly rare in 

 the Mare, though it is very dangerous ; as in attempting to remove it there 

 is great risk of haemorrhage. 



With the Cow, because of the multiple placentulae, the number of which 

 may be over a hundred, the adhesion between the uterus and foetal mem- 

 branes is very intimate ; while the small volume of the cotyledons offers 

 but little surface for the uterine contractions to act upon. So that while 

 it happens that the calf is never born in its intact envelopes, it also occurs 

 that the afterbirth is only slowly and tardily extruded : two, four, or more 

 hours, or even days, being required ; and, indeed, it is not at all rare for 

 retention to take place in this animal, and the envelopes require to be 

 removed artificially. 



Multiparous animals get rid of the envelopes as they expel the foetuses, 

 the birth of the first being followed in a very brief space by its mem- 

 branes ; after which comes the second foetus, then its envelopes, and so 

 on ; so that only those of the last foetus may be retained — an accident 

 which sometimes occurs. In these animals, the membranes appear to 

 be expelled without any difficulty ; the Bitch, for instance, runs into a 

 corner, and assuming a position as if about to micturate, expels the 



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