DISEASES OF THE GENERATIVE ORGANS 367 



DIFFICULT PARTURITION FROM NARROW PELVIS. 



A disproportion between the foetus got by a large stallion 

 and the pelvis of a small dam is a serious obstacle to parturi- 

 tion sometimes seen in the mare. This is not the rule, how- 

 ever, as the foal up to birth usually accommodates itself to 

 the size of the dam, as illustrated in the successful crossing 

 of Percheron stallions on mustang mares. If the dispropor- 

 tion is too great the only resort is embryotomy. 



FRACTURED HIP-BONES. 



More commonly the obstruction comes from distortion and 

 narrowing of the pelvis as the result of fractures. (Plate 

 XIV, Fig. 2. ) Fractures at any point of the lateral wall or 

 floor of the pelvis are repaired with the formation of an ex- 

 tensive bony deposit bulging into the passage of the pelvis. 

 The displacement of the ends of the broken bone is another 

 cause of constriction, and between the two conditions the 

 passage of the foetus may be rendered impossible without 

 embryotomy. Fracture of the sacrum (the continuation of 

 the backbone forming the croup) leads to the depression of 

 the posterior part of that bone in the roof of the pelvis and 

 the narrowing of the passage from above downward by a 

 bony ridge presenting its sharp edge forward. 



In all cases in which there has been injury to the bones of 

 the pelvis the obvious precaution is to withhold the mare 

 from breeding and to use her for work only. 



If a mare with a pelvis thus narrowed has got in foal in- 

 advertently abortion may be induced in the early months of 

 gestation by slowly introducing the oiled finger through the 

 neck of the womb and following this by the other fingers 

 until the whole hand has been introduced. Then the water- 

 bags may be broken and with the escape of the liquid the 

 womb will contract on the solid foetus and labor pains will 

 ensue. The foetus being small it will pass easily. 



TUMORS IN THE VAGINA AND PELVIS. 



Tumors of various kinds may form in the vagina or else- 

 where within the pelvis, and when large enough will ob- 



