20 
It is a matter of daily observation that metritis causes 
sterility, and the authors who have treated the question 
admit it, of course, as one of the causes; but they do not pay 
as much attention to it as to the diseases of the ovaries, con- 
sidering, as a matter of fact, only the very distinct cases with 
much discharge and large accumulation of exudate, and 
overlooking the more chronic and less impressive conditions. 
Zschokke notes as obvious that a fecundation is impos- 
sible if the uterus mucosa is infected and covered with pur- 
ulent discharge; the estrum too is generally absent under a 
catarrhal condition of the metra. It is possible that even 
very slight and otherwise quite insignificant infections pro- 
duce sterility by an acid or toxic exudate, which renders 
the spermatozoa immobile. There is further the possibility 
that sometimes the uterus mucosa is destroyed through a 
protracted inflammatory process; it is known that cows 
which have suffered for a long time from a metritis do not 
conceive again even if they recover and have estrum periods 
again. 
Wapt has found that 40% of all cows with a cured metri- 
tis remain sterile and Fiorentini made the diagnosis of ca- 
tarrhal metritis seventeen times in fifty cases of sterility. 
Zschokke several times found calcification of the cotyledones, 
atrophy and sklerosis of the uterus mucosa, all of which is 
generally the result of a chronic metritis. Martin Poulsen 
states that diseases of the uterus are not infrequently the 
cause of sterility, but he does not pay much attention to them 
and thinks the secondary lesions of the ovaries to be the by 
far most important cause. 
K. Nielsen (Sorring) considers the granular venereal 
disease as the predominant cause of sterility in cattle, and 
employs a corresponding treatment. 
The contentions of Poulsen and of Nielsen are based on 
clinical observations and not on histological examinations, as 
it is very difficult for the practitioner to work in that line. 
It is also difficult for the practitioner to procure the material 
