TREATING INFECTIOUS MAMMIT1S IN THE COW. 
13 
In order to explain this attack, one must assume that the 
affected animal in normal condition was resistant to infectious 
mammitis, and that only during the time of general debility 
were the streptococci able to gain the ascendency and exercise 
their disease-producing power. A like weakening might be 
brought about by other causes, perhaps by the more severe 
bladder disease. The attack of fever, which is hardly to be 
attributed to the udder catarrh, may be regarded as proof 
of it. 
It has been proven by numerous observations that such im¬ 
pairment of the resisting power, especially that brought about 
by chills of all kinds, opens the way for the appearance of in¬ 
fectious mammitis, only of course when the infection is present. 
So the disease appears frequently when white turnips are fed ; 
when the change to pasture is made ; in cold weather, especially 
when cold, damp grass must be fed, and after drinking very cold 
water. The outbreak' is sometimes occasioned by chilling of 
the skin and by draughts. 
Often the disease halts in its course; in other cases it sub¬ 
sides as soon as the predisposing causes are removed. This is 
true of the cases cited above, as well as of the follow¬ 
ing : 
A spotted cow, pregnant ten weeks, owned by M. B., which 
had been affected with infectious mammitis in three quarters of 
the udder since June 3d, and which yielded only 585 cm. per 
day, was on June 20th of last year placed in this institution for 
experiments in treatment. The green fodder formerly fed was 
replaced by hay. As a precaution, suggested by earlier obser¬ 
vations, we leave experimental animals two or three weeks 
without treatment in order to observe the bejiavior of the dis¬ 
ease under the changed conditions. If no improvement occurs 
during the time, then the experiments are commenced. 
On the 23d of June the milk of the cow mentioned cleared 
up and the sediment disappeared. From the 29th of June on 
no streptococci were to be found and every particle of pus had 
disappeared. The mess of milk rose to 1350 cm. The cow had 
