STREPTOCOCCI IN COMPARATIVE PATHOLOGY. 
777 
animals was reported to be the same. Unfortunately, I was 
unable to secure any of the udders for a more thorough exami¬ 
nation. 
In a dairy which has been under close observation by Mr. 
A. R. Ward, Dairy bacteriologist to the Cornell University 
Agricultural Experiment Station, one cow was found to be 
troubled in one quarter of the udder with an inflammatory pro¬ 
cess which caused thickened masses in the blood-stained milk. 
From this milk a streptococcus was isolated in pure culture 
which could not be differentiated from the one obtained from 
the specimens from the cows in the outbreaks mentioned. An¬ 
other cow in this herd has her udder permanently* infected with 
a streptococcus. Another animal in the same dairy suffers re¬ 
peatedly from acute streptococcus mastitis. 
I have under comparison at the present time two cultures 
of streptococci, one of which was secured from the second out¬ 
break of mastitis mentioned above, and the other from a sup¬ 
posedly healthy udder. Thus far I have been able to find cer¬ 
tain morphologic and slight cultural differences between them. 
The streptococcus from the healthy gland grows in much longer 
chains and the individual segments are smaller than those in 
the other. It should be noted, however, that streptococci are, 
or have been in my experience, very rare in milk and in the ex¬ 
amination of the normal udders of twelve cowsf they have not 
been detected in a single instance. 
During the last three years I have made a large number of 
bacteriologic examinations of the changed milk from isolated 
cases of udder disease. As a rule, very few bacteria were found 
and there was no uniformity in the species. With the excep¬ 
tion of the single case cited, streptococci were absent. 
* This organism has constantly been found in frequent examinations of the milk from 
this cow for a period of more than two years. 
f For details concerning these examinations see forthcoming Bulletin (No. 177,") Cornell 
University Agric. Exper. Station, by Mr. A. R. Ward, who was associated with me in 
certain of these examinations. The udders were taken from milch cows killed for tu¬ 
berculosis, but in which the tuberbulous lesions were restricted to one or two glands in 
the throat or thorax. 
