Zi 
for these investigations, and nearly all histological research 
made on the genital organs of cows have had another object. 
Tuff was the first to make histological sections on a big scale 
to clear up the cause of sterility in cattle. 
He examined the genital organs of ninety-seven sterile 
cows and found sixty-four times pathological conditions in 
the vagina, in the os uteri, in the uterus proper, in the 
oviducts or in the ovaries. The uterus lesions were the most 
frequent, being found in fifty-eight cases, mostly catarrhs, 
and quite often of little intensity. In one case, tuberculosis 
of the uterus was noted. In the vagina he found cysts of 
the Gartner ducts, follicular vaginitis and scar formations. 
Six times the oviducts were the seat of inflammatory pro- 
cesses, four times in connection with a catarrhal metritis. 
Yellow bodies were found in sixty-eight cases, thirty times 
connected with cyst formation; in fourteen cases only cysts 
were found. 
The lesions of the uterus are of different nature, accord- 
ing to their location and intensity if only the mucosa is af- 
fected, the lesion is called an endometritis; if it is more pene- 
trating, a metritis, and if involving the serosa, a peri- or para- 
metritis. 
The most frequent form to come up for treatment in 
sterility cases, is the chronic endometritis and the pyometra. 
Tuff found that an interstitial endometritis can exist with 
or without defects of the uterine glands, which may be 
present in smaller or larger numbers. If the first condition 
is present, the uterus will be of normal size, the mucosa of 
normal appearance or slightly injected, covered with much 
mucous matter, the uterine glands normal, the connective 
tissue increased, poor in cells and disposed in strong fibrous 
strands, the walls of the blood vessels thickened. 
Those lesions were found seventeen times. In the cases 
of interstitial metritis where the number of the uterine 
. glands are diminished, which were found twenty-four times, 
the lesions are more distinct; the horns of the uterus are 
, 
