12 
E. ZSCHOKKE. 
in the same manner, and in which cases there were to be found 
long streptococci in this animal and short in that, lead to the 
belief that there are not two species of streptococci associated 
with the disease, but only one. 
Indeed, the earlier observation that the streptococcus of in¬ 
fectious mammitis varies in size according to the medium upon 
which it is grown establishes the fact of the variability of this 
form. It grows in short chains or clumps on agar cultures and 
in long chains in serum or condensation water. It appears that 
the conditions of existence in the udder are very dissimilar in 
different animals. This dissimilarity is to be attributed to 
every obstruction which we encounter more or less in every in¬ 
fection and which is usually termed resistance. This resistance 
seems to be quite variable. 
We observed a case of short-chain streptococcus infection 
which recovered fully twice and again appeared a third time, 
fifteen to twenty weeks after parturition. Here was a very 
slight resistance, the quality of which was not lessened by the 
single onslaught of the disease, nor in this case was immunity 
conferred. 
On the other hand, there have been recognized, in goats as 
well as cows, numerous cases of spontaneous recovery, as well as 
rare cases of failure to infect in spite of inoculation. 
On the 8th and nth of May, 1899, I inoculated two cows, 
with healthy udders, and two goats, using about 20 cm. of 
fresh infected milk from a case of infectious mammitis and 
which was very rich in streptococci. But it induced the disease 
in only one cow in the ordinary period of from three to five 
days. 
One goat exhibited a continuous power of resistance. One 
cow exhibited the disease first on the 28th of May. She had 
also a few days before suffered from hsematuria, losing a con¬ 
siderable quantity of blood and had shown a rise in temperature. 
After the cow had recuperated a few days, the pus and strep¬ 
tococci disappeared from the milk, so that by the 3d of June it 
was less slimy and became fully normal again on the 6th of June. 
