08 A Nan' Dairy Industry. 



the milk has not been counteracted or suspended, but 

 has, on the contrary, been favored. 



Bacteriology has taught us that an alkaline reac- 

 tion is extremely conducive to the welfare of bacteria, 

 therefore the addition of this chemical may for several 

 hours disguise the acidity, but in no manner will it 

 retard the curdling, with which end in view it has 

 probably been added. Milk treated with soda and 

 kept at a temperature of 80 F. will keep from 

 becoming sour for from twelve to twenty-four hours ; 

 at 95 F. for from six to ten hours, while the curdl- 

 ing, however, has by no means been retarded. 



A simple experiment will show that the curdling 

 sets in at about the same time in samples of pure 

 milk and in such treated with soda, if kept at the 

 same temperature. As the beginning of curdling in 

 all pure milk is nearly entirely dependant on the quan- 

 tity of milk acid formed therein, it would seem at 

 first sigl;t as if this result were contradictory. We 

 have, however, seen that the curdling of milk is not 

 only enacted by such bacteria, which produce acidity, 

 but also as well by a large number of other species of 

 bacteria which have the faculty to produce a rennet- 

 like ferment. By a low alkaline reaction the propa- 

 gation and multiplication of bacteria in milk is 

 favored and, therefore, also their effect, so that the 

 dulling of the acid is compensated by the more rapid 

 development and increased activity of the rennet pro- 

 ducing bacteria. For this reason the result of such in- 

 vestigations depends largely on the quantity of rennet 



