THE RIPENING OF CREAM. TeurnT 
From these facts it would at first appear that the ripening 
of cream is to be attributed wholly to the acid bacteria. Cer- 
tain it is that these bacteria are the ones which grow most 
abundantly during the ripening and are present in large pro- 
portions at itsclose. We were at first inclined to believe there- 
fore that the ripening of cream is to be attributed to the lactic 
organisms alone. Further consideration and some further ex- 
periments have led us to doubt this, without leading us yet to 
any definite conclusion. It will be noticed that during the 
first few hours of ripening, z. e., during the hours in which 
the cream is separating from the milk by the gravity method 
and the twelve hours following, other bacteria than the lactic 
species have been multiplying. Cream that is twenty-four 
hours old from the time the milk is drawn from the cow con- 
tains a vast proportion of miscellaneous bacteria and only a 
small number of acid bacteria. It is certain that a considera- 
ble part of the cream ripening must have occurred before this 
time, and that the later ripening of the cream simply completes 
the process. Up to this time the lactic bacteria have been so 
few that they could have had little or no effect upon the cream. 
All of the changes then in the first twelve to twenty hours 
must be attributed to other bacteria than the acid organisms. 
Moreover, it will be seen from the tables that, though the fer- 
centage of miscellaneous bacteria constantly decreases, their 
numbers actually increase fora while. For example, the lique- 
fying bacteria in the fifth experiment were present in the fol- 
lowing numbers in the first five tests: 3,500, 21,000, 1,540,000, 
2,700,000, 1,500,000. The actual numbers were increasing 
although the proportion decreased from 8 per cent. to .1 per 
cent. In one or two experiments on June’ butter the increase 
of liquefiers in the first twelve hours was much larger, so great 
indeed that it was impossible to estimate the number of bac- 
teria on the plates because of the complete liquefaction of the 
gelatin. These facts of course show that during the first 
twelve hours of ripening other bacteria than the acid bacteria 
are multiplying and must produce an influence upon the cream. 
It would seem, therefore, that the ripening of cream must 
consist of two phases: the first comprising the first twelve 
hours or more of ripening and due to the growth of miscella- 
neous bacteria; the second beginning after twelve hours and 
