44 
took three, four and even five weeks, which still can not be 
called pathological. 
I made the further observation that cows may have a 
benign metritis without having any discharge or without 
being disturbed in their general condition. In these cows 
the uterus is often more or less enlarged even to the extent 
that it cannot be encompassed with the hand; there is also 
quite often an excretion in the uterus. Generally these ail- 
ments are benign; they are caused by an infection which’ 
prevents the involution of the uterus. 
If the apparent metritis cases are added to the less 
obvious ones which can be made out only by an elaborate 
examination, the total number very nearly equals the number 
of sterile cows. 
It is, therefore, apparent that the majority of sterility 
cases are caused by inflammatory processes of the uterus, 
which themselves are caused by infection. 
The fact that so often many or even all animals of a 
herd are diseased, and that the symptoms are so very differ- 
ent in different herds or individuals, can only be explained 
by the fact that the infections are of a different nature hence 
of a different virulence. This also explains the continuity 
of sterility complaints in certain herds. 
It is a well known fact that puerperal infection is endemic 
in many stables, and also that these infections may vary with 
the locality. This is, for example, demonstrated by the 
difference in time in which the secundinae may become de- 
composed. In contagious abortion, where the placenta is 
the seat of inflammatory and exsudative processes, the 
secundinae decompose more quickly than in normal cows. 
Even in the latter the conditions may vary very much, so 
that in one case the placenta is found to be decomposed after 
a few hours and in others even after days to be very little 
changed. The only explanation for this is the difference in 
the distribution and in the virulence of the infectious mater- 
ial. In some stables it is impossible, to prevent malignant 
