26 STORRS AGRICULTURAL EXPERIMENT STATION. 
growing side by side. ‘The importance of the matter to the 
butter-maker is considerable, inasmuch as it indicates that it 
may be possible, by inoculating cream quite heavily with one 
kind of bacteria, to check the influence of the other kinds 
which may be present. One can thus obtain the influence of 
the inoculated species but little modified by the growth of the 
other bacteria which are present in less abundance. During 
the last year or two butter-makers have become convinced of 
the advantage of using starters. They have found that in 
many cases the use of a starter, either a natural starter or one 
of the various pure cultures which are on the market, will 
improve their butter where it is added to ordinary cream. It 
has been something of a question how a starter can do any 
good in cream already more or less impregnated with bacteria. 
But if, as these experiments show, such a starter has the power 
of checking the growth of normal bacteria, we can understand 
the matter. If starters can have any influence checking the 
growth of bacteria already present we should expect that such 
starters would frequently improve butter, although not always. 
Thus, the facts here given offer an explanation of and empha- 
size the value of a starter of some kind in cream, both for the 
purpose of starting the proper kind of ripening, and also to 
check the development of many bacteria already present which 
might be injurious to the butter. 
MOST BACTERIA HARMLESS OR BENEFICIAL. 
Second.—The majority of the species tested may be regarded 
as indifferent in their effect upon the butter. About Halr 
of them when used to ripen the cream, as will be seen in the 
experiments described below, produced butter that had neither 
flavor nor aroma nor acid, and the butter was practically indis- 
tinguishable from the control butter. These species are the 
largest in number and present in the greatest variety around 
barns and dairies. They are perfectly wholesome in the cream. 
They do no injury, they do no special good, and we may, 
therefore, conclude from this that the majority of the species 
of bacteria that are present in the sources of our milk are 
wholesome forms, which may grow and develop in the cream 
without producing any trouble, and are perfectly consistent 
with the best quality of butter. 

