Occlusion of the Os Uteri 253 



is exceedingly diificult to insert even the little finger through the 

 canal into the uterus. In a perfectly normal uterus of the cow, 

 it usually requires half an hour to one hour of hard work to dilate 

 the part sufficiently to insert an index finger. The cervix of the 

 cow is so hard that it frequently leads the inexperienced veter- 

 inarian to diagnose sclerosis when it is perfectly normal and thus 

 lead to.an error in reference to the cause of sterility and an equal 

 mistake in applying remedies for the sterility. Zschokke has 

 searched in vain for cartilaginous tissue in the cervixes of cows, 

 but has occasionally met with an excess of connective tissue' 

 which has led, in his judgment, to some sclerosis. Even this, 

 he admits, is very seldom. Zschokke, in his extensive experience, 

 has never met with a case of atresia of the os except as a con- 

 genital affection, and even then only very rarely. 



It is very evident that, if the mouth of the uterus is completely 

 closed, neither the penis nor the semen can enter, because of the 

 anatomical relations, which have been already discussed. It is, 

 accordingly, an old custom in all countries to examine the cervix 

 uteri in cases of sterility to determine if it is open or not. 



The frequency of occlusion of the os uteri is a question which 

 admits of much discussion and which is differently answered by 

 different practitioners. In the judgement of some veterinarians, 

 it constitutes the chief cause of sterility, while by others it is re- 

 garded as a very rare and more or less mythical condition. Hess 

 passes over the question of occlusion of the os very lightly, while 

 Zschokke considers it of much importance and of comparatively 

 frequent occurrence. Bass deems it one of the great causes of 

 sterility in the cow. 



It is difficult to harmonize these conflicting views. It is con- 

 stantly to be remembered that an os uteri is not closed, so far as 

 conception is concerned, so long as the canal will admit of the 

 passage of a small probe. There is no essential reason why the 

 OS uteri externum should be any wider than the canal of the 

 oviducts, which barely admit the passage of a large horse hair. 

 The anatomical character of the cervix of the cow renders it ex- 

 ceedingly difficult to determine if such a passage exists or not, 

 until the os has been sufficiently dilated to permit the passage of 

 a fi.nger into the uterine cavity. According to Zschokke and 

 others, the occlusion of the os, or a harmful stricture, has been 

 met with in animals which have recently given birth to young 



