126 



BOVINE OBSTETBICS 



JEtioloyy. — Mummification occurs after death of the foetus 

 only uuder following conditions : 1. When the air is absolutely 

 excluded. 2. When expulsion is prevented. 



The foetus usually dies between the fourth and sixth 

 month ; in some cases sooner, rarely later ; or at the end of 

 gestatiou death may be caused by interference with the circu- 

 lation, — for instance, after torsion of the uterus (torsio uteri) ; 

 then expulsion is also prevented (Franck). But diseases of 

 the foetus and disturbances in the composition of the blood 

 may cause intra-uterine death of the foetus. Besides torsio 



Fig. 17. — Lithopajdioii. 



uteri, other disturbances making expulsion impossible, may bo 

 auxiliaries, obliteration of the os uteri, wanting labor pains due 

 to fatty metamorphosis of the uterine muscle, adhesions of the 

 walls of the uterus with adjoining organs, in consequence of 

 which the contractions cannot exert their expelling powers. 

 Torsio uteri is the most frequent cause. Many mummified 

 calves have distinct parallel grooves on their surface from the 

 folds of the twisted uterus (Franck). In extra-uterine preg- 

 nancy, lithopsedions may also form. (See "Extra-Uterine 

 Pregnancy.") 



