268 PRINCIPLES OF STOCK-BREEDING. 



the observed cases of this peculiar influence ; and it 

 also fails to take into account certain physiological 

 facts that are difficult to reconcile with it. It is well 

 known that the placenta and decidua are temporary 

 organs that disappear at the time of parturition, and 

 that even the mucous membrane itself is removed and 

 replaced with new tissue. 



Dr. Dalton says : " Another very remarkable phe- 

 nomenon connected with pregnancy and parturition 

 is the appearance in the uterus of a new mucous mem- 

 firane, growing underneath the old, and ready to take 

 the place of the latter after its discharge. If the in- 

 ternal surface of the body of the uterus be examined 

 immediately after parturition, it will be seen that at 

 the spot where the placenta was attached every trace 

 of mucous membrane has disappeared. 



" The muscular fibres of the uterus are here per- 

 fectly exposed and bare, while the mouths of the 

 ruptured uterine sinus are also visible, with their thin, 

 ragged edges hanging into the cavity of the uterus, 

 and their orifices plugged with more or less abundant 

 bloody coagula. Over the rest of the uterine surface 

 the decidua vera has also disappeared. Here, how- 

 ever, notwithstanding the loss of the original mucous 

 membrane, the muscular fibres are not perfectly bare, 

 but are covered with a thin, semitransparent film, of 

 a whitish color and soft consistency. 



" This film is an imperfect mucous membrane, of 

 a new formation, which begins to be produced under- 

 neath the old decidua vera as early as the beginning 

 of the eighth month." 1 



1 "Human Physiology," pp. 621, 622. 



