17 
percentage observed. It is closely connected with infectious 
abortion, retentio secundinarum, metritis, but can be found 
also without these foregoing complications. Through his 
very numerous examinations of sterility cases in different 
environments he comes to the conclusion that the corpus 
luteum persistens is the most important and the most com- 
mon cause of sterility in cows. 
E. Hess gives a detailed report of his investigations in 
this line. He too contends that the most frequent cause of 
sterility in cattle are diseases of the ovaries. He pays more 
attention however to the cystic degeneration of the ovaries 
than to the yellow bodies. Apparently nymphomania is an 
ailment of much importance in his part of the country, for 
he gives all the symptoms, one of which is sterility, of course, 
and advises as a therapeutic measure the rupture of the cysts 
through the vagina. If heat is absent, he also finds quite 
often cystic degeneration (in which case the cysts are, how- 
ever, of a more flaccid constitution), and frequently the per- 
sistent yellow body. It is remarkable that he treats pyo- 
metra also with the removal of the yellow body; he claims 
that this operation and the gentle massaging of the uterus 
are much more efficient therapeutic measures than the irriga- 
tion of the uterus. 
W. L. Williams in his book: Veterinary Obstetrics, gives 
much space to the discussion of sterility in domesticated 
animals. He reconsiders the work of Hess, adds some of his 
own observations, and gives with many references a very 
complete review of the whole question. 
We see that there is an inclination to connect sterility in 
cows primarily with pathological conditions of the ovary. 
Such a point of view can not be criticised if the consequent 
methods of treatment give practical results. It is not so im- 
portant here that there are ostensibly other causes which 
may cause sterility, since we must strive to satisfy our cli- 
ents with successful treatments, and not with the most 
plausible explanations. 
