
BACTERIA IN THE DAIRY. 31 
there is a greater chance of finding not only those producing 
acid, but also some which give rise to an aroma. 
It has been found in these experiments thus far that none of 
the species tested combines all of the three characters—the 
power of producing flavor, acid, and aroma. Some develop 
flavor with the acid, others develop aroma with flavor, and 
others develop aroma without any special flavor. As yet no 
single species has been discovered that produces all simultane- 
ously. ‘This result is not, of course, surprising, for, recog- 
nizing that the ripening of cream must be an extremely 
complicated process, and produced by a large number of spe- 
cies of bacteria working together, it is a natural inference that 
the different qualities in the butter may be caused by different 
species of bacteria. It is by no means to be implied, how- 
ever, that the three properties may not be combined in some 
species of bacteria. 
Lastly, it is interesting to note that among the species of 
bacteria which produce good flavor in the butter, are found 
some that were quite widely distributed during the month of 
June. ‘There was one species in particular, which, in my 
experiments, was described as giving rise to a good flavor and 
a strong acid, which was found during the months of May and 
June in each of the creameries from which samples of cream 
were taken. ‘This, of course, is suggestive as indicating per- 
haps a reason for the common production of a good quality of 
butter during these months. 
SUMMARY. 
rt. The cream in ordinary creameries or in ordinary dairies 
always contains bacteria, a large majority of which are perfectly 
wholesome, and which give rise etther to good flavors and aromas 
in the butter or, at least, produce no injurious effect upon the 
cream, They are perfectly consistent with the production of the 
best quality of butter. 
2. In the months of May and June the variety and the num- 
ber of these types .of bacteria is decidedly greater than in the 
winter months, and this probably explains, in part, the better 
quality of butter at these seasons. 
Me Occasionally a dairy or a creamery May be impregnated 
with a species of bacteria that grows rapidly and produces a 
