408 STATE BOARD OF AGRICULTURE. 



The percentage decrease of bacteria has no relation to the absolute number 

 in fresh butter. The absolute number of lactic acid bacteria in fresh or old 

 butter has nothing to do with the scores. The percentage decrease also did 

 not agree with the scores. In the warmer storage a^ and as the lactics have 

 practically disappeared; in some of the samples the destruction was so com- 

 plete that even if 1-100 cc. of the butter fat were transferred to sterile milk 

 there was no acid produced. 



The influence of salting has never been the subject of a very extensive 

 bacteriological study. Since the salt of the butter is only dissolved in 

 the water of the butter, we have quite strong salt solutions. A butter with 

 2% of salt and 15% of water has a brine concentration of 13.4%. This so- 

 lution plasmolyzes most of the bacteria, but not all. We know that the 

 effect of plasmolysis on bacteria is not very pernicious; it prevents their 

 multiplication, but, for instance, not the motility. Besides that, several 

 kinds cannot be plasmolyzed at all, as e. g., Bac. suhtilis and B. anthracis 

 (Lafar I, p. 63). We know other bacteria that are able to multiply readily 

 in concentrated salt solutions, for instance the bacteria of the salted fish; 

 Levandowsky isolated several kinds from saturated salt solutions. Wehmers 

 Salt Yeast was only retarded in its growth by adding 15% salt (Lafar IV, 

 p. 290). Gorini (Rev. Gen. du Lait IV, 1904, 73) found a gas-producing 

 coccus which multiplied rapidly in a 20% brine solution. This agrees with 

 the experience of the dairymen who used strong brine for cleaning or pre- 

 serving the tubing of the milking machines. It was quite impossible to pre- 

 vent growth by application of salt only, no matter how strong the solutions 

 were. 



These facts explain why even high salted butter does not keep indefinitely. 

 But there is no doubt, of course, that salt is a very valuable factor for keeping 

 butter for some time, because it certainly retards the growth of all micro- 

 organisms. 



NON- LACTICS AND LIQUEFIERS. 



The decrease of the non-lactic bacteria (Table XII) is in November about 

 the same as that of the lactics; in February, however, there is no further 

 decrease, but apparently a slight increase of non-lactic bacteria. Table 

 XIII shows that this increase is mostly due to the liquefying bacteria. This 

 result is certainly interesting, since it is an average result from 16 different 

 samples, and makes it more probable that the rancidity of cold storage butter 

 is connected with a decomposition of protein substances. This increased 

 number of liquefiers is mostly due to Bacterium lactis lohatum, Bact. I. album, 

 Bad. I. Gorinii and Bacillus I. cochleatus. The liquefying cocci have no 

 pronounced increase. 



THE FREQUENCY OF THE MICRO-ORGANISMS. 



We were somewhat disappointed in our work when we saw that there were 

 no micro-organisms regularly present in butter except the lactic acid bac- 

 teria. 



In dividing all bacteria in the 6 morphological^ groups and subd v ding 

 into liquefiers and non-liquefiers, we get the following table : 



