vn] BACTERIA IN BUTTER-MAKING 127 



have been found growing in ripening cream may 

 produce all sorts of disagreeable flavours. While 

 pleasant flavours seem to belong to the first products 

 of decomposition, those formed during the later 

 stages give rise to disagreeable ones. 



Since, then, the great danger in ripening is to con- 

 tinue it too long, and thus induce a disagreeable flavour 

 in the butter, a point of first-rate practical importance 

 is to determine the proper length of time for ripening. 

 But this is just exactly what it is very difficult to 

 do. The butter-maker can have no certainty that 

 his cream is supplied with the proper species of 

 bacteria ; hence the importance of being able to 

 furnish to butter-makers the proper ferment, and 

 thus avoid all such risk. Investigation into this 

 subject is but in its initial stages, and only one 

 species of bacteria has as yet been discovered which 

 produces the proper results. It is along this line of 

 investigation that the most useful results from future 

 researches in the science of butter-making are to be 

 looked for. We are the more encouraged to expect 

 this on the analogy of the great benefits which have 

 accrued to the brewing industry from the application 

 of similar principles. The great uncertainty which 

 accompanied the manufacture of beer in former 

 times has been greatly reduced by the use of pure 

 yeast cultures. As illustrating the intimate connec- 

 tion between bacterial life and flavour in butter, it 



