24. STORRS AGRICULTURAL EXPERIMENT STATION. 
to find out the particular species which produced the best but- 
ter, I have thought that this method of testing several species. 
simultaneously promised the most valuable results. 
RESULTS. 
In general the results of these experiments have been con- 
firmatory of those of the series already given in a previous 
publication (Bulletin No. 12). Nevertheless, a number of new 
facts of interest and importance have appeared. The most 
important of these results are the following: 
CONTROL CREAM COMPARED WITH INOCULATED CREAM. 
First.—One of the most interesting facts was found in com- 
paring the control (2. e., the pasteurized but not inoculated ) 
samples of cream, and butter made therefrom with the inocu- 
lated samples. Asa rule the control butter possessed neither 
flavor nor aroma—in no case unless the ripening had continued 
too long. Nevertheless, it was found in many cases that the 
control cream dzd undergo some decided changes during the 
period of ripening. The temperature of 158° F. (used in pas- 
teurizing) does not kill all the bacteria in the cream, and the 
subsequent ripening being somewhat long and the temperature 
somewhat high, the few bacteria that were left in the cream 
after pasteurization had an opportunity to develop. The cream 
thus frequently showed the effects of their presence. In many 
cases the control cream was thick and nearly curdled, but in- 
asmuch as it was never acid, it was plain that this effect was. 
due, not to the lactic acid organisms, but rather to the growth 
of the species of bacteria which curdle milk by the production 
of a rennet ferment; a class frequently called the putrefac- 
tive class of bacteria. This is readily understood, since these 
bacteria frequently produce spores which resist heat, while 
the acid bacteria produce no spores. In a few cases the 
control cream became slightly bitter or developed some other 
unusual taste, but the taste was so slight that it had no effect 
upon the butter made from the cream. ‘These facts, of course, 
are not surprising, for they are exactly what would have been 
expected when we remember that pasteurization does not 
destroy all the bacteria present in the cream. The interesting 
fact in these experiments was that in no case did the inoculated. 
lots of cream show similar results. Where the control cream. 
oe 
