Mar. 25,1914 
Streptococci in Milk 
493 
represent the normal streptococci of milk but rather those which would 
usually be distinguished as indicating contamination from infected udders 
or fecal sources. 
Fifty-one cultures were isolated from 19 samples of milk obtained 
by milking directly into sterile test tubes. The cows from which these 
samples were obtained represented all gradations of infected udder 
from occasional evidence of garget to acute mammitis. Part of these 
were in the Dairy Division herd at Beltsville, Md., and the remainder in 
the herd on the Naval Academy farm at Annapolis, Md. One hundred 
and fourteen cultures came from 56 samples of cow manure obtained t 
with the exception of a few from Troy, Pa., at the Dairy Division farm 
and at the dairy of the Government Hospital for the Insane at Wash¬ 
ington. Thirty-nine cultures were made from the mouths of animals 
at the Dairy Division farms. With the exception of one culture obtained 
from the mouth of a mule, all of these cultures were of bovine origin. 
In Table II the origin of the culture is indicated by M for milk, U for 
udder, F for feces, and B for mouth. The sample from which the culture 
was secured is indicated by a number following the letter. For instance, 
“F15” represents sample of feces No. 15. This will enable the reader 
to determine the origin of each culture and the number of cultures from 
each sample. 
MORPHOLOGY OF THE CULTURES 
While it is generally recognized that there is little morphological basis 
for subdivisions of the streptococci, reference is frequently made to 
certain types of cells. Stowell, Hilliard, and Schlesinger, 1 in selecting 
streptococci from milk for comparison with those isolated from the 
human throat, rejected diplococci and the oval-chained form which they 
designate as the Streptococcus lacticus of Kruse or the Bacillus lactis 
acidi group, respectively. In selecting our cultures no attention was 
paid to morphology beyond determining that it was a coccus apparently 
dividing in one plane, with the exception of those from milk, which were 
not accepted if they did not form chains of at least 8 or 10 cells. The 
morphology of nearly all cultures was determined by examination of 
specimens stained with gentian violet. Camera-lucida drawings were 
made using a Eeitz 3 mm. objective and No. 18 ocular, a combination 
which gave a magnification of 2,400 diameters at the ocular, or 4,800 
diameters on the drawing board. Sufficient light to give a clear image 
was obtained by using a special arc light with a copper-sulphate ray 
filter. 
Preliminary studies showed that the medium on which the culture was 
grown had an appreciable influence on both the size and the form of the 
cell. This is shown in figure 1, which is reproduced from camera-lucida 
drawings of typical cultures grown on various media. Milk gave quite 
1 Stowell, B. C., Hilliard, C. M., and Schlesinger, M. J., A statistical study of the streptococci from milk 
and from the human throat. Jour. Infect. Diseases, v. 12, no. 2, p. 144-164. 1913. 
