66 STORRS AGRICULTURAL EXPERIMENT STATION. 
became slightly more acid but produced very good butter. No. 
18 became decidedly acid and bitter and produced strong, rank 
butter. ES aaa 
The consideration of the pairs of experiments as shown above, | 
plainly shows the difference in the butter of different species of Z 
bacteria when used in ripening the cream, and, in addition, indi- % 
cates that the method of experiment was rigid enough to obtain 
at least approximate results in all cases. 
Vv Another point brought out clearly in these experiments was 
the effect of the washing of butter. Nearly all of the flavor pro- 
duced by the ripening of the cream was in the buttermilk, and 
the taste of the butter was very much more prominent without 
thorough washing than it was after such washing. If the butter 
was washed long enough, all of the aroma would be washed out, 
while without any washing at all, the taste was most prominent. 
The butter aroma is then not due to changes in the fat, but to 
some other constituents of the cream. For this reason it was 
our custom to taste the butter before any washing had occurred, 
as well as after the working, and in this way a stronger effect 
was noted and the differences between the organisms made out 
with more ease. ‘This fact, that the aroma is due to the butter- 
milk, is not a new one, but it was plainly brought out by the 
experiments. 
It should be stated that in all of these experiments the differ- 
ences in flavor of the resulting butter were less than had been 
anticipated before the experiments began. ‘The effect upon the 
taste and flavor of the ripened cream of the different species’ of 
bacteria was very marked indeed, and the effect upon the taste 
of the butter before washing was equally striking. After the 
washing and the working, which removed a considerable portion 
of the buttermilk, the differences in flavor were very much less 
noticeable, so much so that in some of the experiments it required 
the utmost attention to make out the'appropriate differences 
between different specimens of butter. It is true that the differ- 
ences above noted in the experiments were always seen in the 
specimens of butter tested, but it is equally true that those differ- 
ences were not in many cases very striking ones. Many of the 
forms of butter which have been described as poor or moderate 
would probably pass muster as tolerably good butter. At the 
same time, in the case of a few of the organisms, especially No. 
27 and No. 162, the effect upon the butter was in itself very 

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