114 Report of the Department of Bacteriology of the 



demonstration of the correlation between the germ content of 

 quarters of an udder and the rate at which milk from these 

 quarters underwent auto-digestion in the presence of chloroform. 

 These results were not intended as a demonstration that all of the 

 enzymes in milk were derived from bacteria but rather as a sug- 

 gestion that bacterial enzymes within the udder are a factor which 

 must be considered in studying true milk enzymes. 



The fermentative activity of the udder flora is especially in- 

 teresting. No visible gas is formed from dextrose, lactose, saccha- 

 rose or glycerine when tested in the fermentation tube. This is 

 not due to inability to attack these substances since acid was 

 formed from dextrose by 89 per ct., from lactose by 70 per ct., 

 from saccharose by 63 per ct. and from glycerin by 21 per ct. 

 of the forms studied. 



The technique employed in determining the reduction of 

 nitrates has been already described. Nitrates were reduced by 

 59 per ct. of the forms but in no case was gas detected in the 

 fermentation tube as a result of the reduction. 



The records of color are particularly unsatisfactory in connec- 

 tion with these forms. While the difficulty is partly due to the 

 tardy formation of slight amounts of coloring matter it is more 

 largely due to the fact that the color is frequently salmon pink. 

 Under varying conditions of age, light, moisture and substratum 

 there is a tendency to classify cultures of the same organism 

 under yellow, orange, red, brown and pink. The standard method 

 of classification needs improvement at this point so that direct 

 comparison can be made with standard test objects, using cultures 

 of definite age and composition. The color given in the above 

 table is that observed on the agar slope at the end of two weeks. 



The action of the organism upon starch was judged by crushing 

 fourteen-day potato cultures in a mortar and testing for starch 

 with a dilute iodine solution. Where the action upon the starch 

 was slight the fact was often best determined Iry adding the iodine 

 solution to the fluid from the potato culture. The presence- of 

 the first products of starch digestion was shown by a wine ooTo.s. 



