INNERVATION OF THE GENERATIVE ORGANS 569 



any difficulty experienced in delivery usually causes the death of 

 the foal. In Ruminants, on the other hand, the separation of the 

 cotyledons takes place vei'y gradually, so that the connection between 

 the maternal and fu?tal cii'culation is maintained to some extent 

 until the last. In these animals the process of parturition may last 

 for hours (in the cow, al)out two hours; in the sheep, about fifteen 

 minutes for each laml) born). In the mare, on the contrary, 

 delivery is usually effected very rapidly^ (five to fifteen minutes). 

 In the sow, liitcli, and cat it takes from ten to thirty minutes for 

 each .)oung' one born, with sometimes an inter\al of an hour Ijetween 

 the l)irths. The foetal memliranes may be expelled with the young- 



Fiii. 15!). — The foal in tlie normal position foi' delivery, the revolution being 

 completed and the membranes ruptured. (After Franck. Fi'om Smith's 

 \'i'trrii)iir>i I'liii-iiiijagii^ Bailliere, Tindall & Cox.) 



or be retained until a little later, when the uterus recovers its power 

 and then expels tliem (in tlie mare se\-eral liours after the foal 

 is born). 



In the Carni\'ora the mother usually gnaws tlirough the umbilical 

 Cord but in the other animals it is torn. 



In animals such as the rat, in which multiple conception is the 

 rule, the " presentation " of the young at birth may be either " breech " 

 or "head." The tVctuses tend to be expelled irregularly, some being- 



1 Smith (F.), WieriiKiri/ I'lii/xiolugi/, .'jrd Edition, London, 1907. Fleming, 

 Veteriiiarii Obstetiics, Craig's Edition, London, 1912. Wortley Axe, "The Mare 

 and Foal," .four. Roi/al Agrir. Sue, 3rd Series, vol. ix., 1898. Leeney, "The 

 Lambing Pen," Jour. Uoi/al Agrir. Six:., 3rd Series, vol. vii., 1896. Article on 

 "Parturition" fiy the same authoi' in The /Standard Gydopedui vf Modern 

 Aqrirvitiirr, vol. ix., London, 1910. 



