II2 REPORT OF DEPARTMENT OF BACTERIOLOGY OF THE 
resentatives of this type differ in their relation to air and in their 
ability to attack saccharose so that they are found under four dif- 
ferent group numbers. As will be shown later they differ in a num- 
ber of other particulars. Str. lacticus, which includes two differen 
group numbers, is occassionally found in much smaller numbers. 
These groups apparently agree with the corresponding groups of 
Bact. lactis acidi in every thing except morphology. The position 
taken by Conn, that there is a distinct morphological basis for the 
separation of the cocci from the rod forms, appears to be well 
taken. Both the morphology and the physiology of these groups is 
easily influenced by their environment and it is especially impor- 
tant that the cultures be brought to a vigorous condition before 
being subjected to detailed study. 
The acid liquefiers which are considered so important by Gorrini 
are represented by M. lactis albidus (2 groups), M. lactis giganteus, 
M. lactis varians (4 groups), and WM. lactis brevis. M. lactis al- 
bidus and M. lactis brevis occurred sufficiently often to suggest that 
they might play some part in the ripening changes. Representa- 
tives of this group were found in all but Cheese 4.6 VIII. These 
forms grew well in the milk but made little headway in the cheese 
although they survived there better than the non-acid-producing 
forms. Their number, as compared to the total germ content of 
the cheese, was relatively insignificant. 
The gas-producing forms, like the preceding group, find the best 
conditions for their development in the milk and make little or 
no growth in the cheese. B. coli aerogenes was found in the milk 
for Cheeses 4.6 VIII and X. In both cases it was not found in the 
cheese after the first day. The isolated cultures were slow gas pro- 
ducers and did not displace more than one-third of the closed arm 
in the fermentation tube. 
Bact. lactis aerogenes was found in Cheeses 4.6 IV, VIII, IX and 
X, in the last three in considerable numbers. In these cases evi- 
dence of gas was noted in the vat during the early stages of the 
making process. These forms are very resistant to the acidity in 
the milk and cheese but our data do not show that they multiply 
in the latter. 
The inert group, characterized by a lack of any apparent action 
upon milk, is represented by Galactococcus versicolor and Bact. lac- 
tis Connu., They are fairly numerous at times in the milk and fresh 
curd. They usually disappear quickly. There is no evidence that 
they increase in the cheese. 
