EXPERIMENT STATION BULLETINS. 275 



The more rapid development of acid in A+B indicates the same results obtained 

 from the gross tests and also points to a more rapid souring of milk in the com- 

 bined culture. 



The next natural question is, do the lactic acid bacteria increase more rapidly 

 in the combined culture A+B than in A? Many counts of bacteria have been 

 made in these cultures at different hours during the progress of the changes 

 going on, and they all plainly show a more rapid increase of lactic acid bacteria 

 In the combined A+B culture than they do in culture A. At the time of lopper- 

 ing, when the members show their greatest contrast, we find A : A+B=27 : 1614. 

 Again, in another exhaustive count, the proportion stands thus: A : A+B=271 

 : 1537. These counts again bear out what has been stated heretofore. 



It is also very noticeable that germs of culture B, as they develop in the com- 

 bine culture A+B, die out completely but gradually before the 50th hour. In the 

 first hours they predominate, but soon lose their ascendancy, leaving, however, 

 a distinct influence in their wake and also a perceptible odor peculiar to this 

 culture. 



If this associative action is borne out with other similar micro-organisms when 

 grown in the presence of lactic acid bacteria, the significance is great, for it will 

 have a direct and practical application to dairy operations, in the matter of pure 

 milk supply, souring of milk, milk fermentations, starters, and their management. 

 Before further discussion, I am desirous of ascertaining how far-reaching this may 

 be, and this can be accomplished by extensive experiments only. The conditions 

 must now be greatly varied and the various germs usually met with in the dairy 

 must be tested in this associative function before conclusions should be drawn for 

 guidance. 



Upon going to press we are able to say that two other micro-organisms have 

 been met which have the same action as B when associated with this lactic 

 acid bacterium; we have also met two others which retard the development of this 

 lactic acid bacterium. Detailed studies will follow later. 



Department of Bacteriology and Hygiene, Jan. 10, 1904. C. E. M. 



