16 
It can readily be seen that sterility comprehends a 
number of pathological conditions which can be of a more 
localised or of a more general nature. Zschokke does not 
emphasize what he thinks important and what of less sig- 
nificance, paying, however, most attention to the ovaries. 
Neither does he give any data on the treatment of his cases, 
or rather on the results of his treatments. In Denmark, not 
much in this line has been done, with the exception of the 
study of contagious abortion. This disease has, however, 
much significance for us, as it is very often the only cause of 
the sexual disturbances. We all agree, of course, that the 
greatest percentage of abortions in advanced pregnancy are 
caused by the abortus bacillus of Bang and Stribolt. 
Aside from contagious abortion we have treated only a 
few of the conditions connected with sterility. They are 
especially: the stenosis of the cervical canal, causing con- 
tinuous nonconception, the cystous degeneration of the 
ovaries in nymphomania, and finally the very frequent per- 
sisting yellow bodies. In a few cases we have treated too the 
follicular vaginitis. Most of the writers have restricted them- 
selves to the study of these conditions. 
K. Nielsen (Sorring) was the first to mention the cor- 
pus luteum persistens as a significant condition in the ster- 
ility of cows. He abandoned the old methods of cervix 
dilatation and uterus irrigation and treated the ovaries by 
pressing out the yellow bodies. He claimed this treatment 
to be successful in most cases of sterility. 
Martin Poulsen (Ringsted) accepted the method, and 
states that pathological conditions of the ovaries are the 
most common cause of sterility in cattle. He has an experi- 
ence of years, and has made systematic examinations of 
pregnant cows. 
He pays much attention to the persistent corpus luteum 
and claims that nearly all cases of sterility are caused by it. 
It is as common in big herds as in small stables, and can be 
found occassionally in 70% of a herd, this being the highest 
