530 



WILLIAM H. CHAMBERS 



The experimental work was divided into two parts: first, the 

 determination of the individual variation in germicidal action in 

 the milk of the eleven selected cows; and second, the variation 

 in action upon pure cultures in the milk of the cows showing the 

 best germicidal action. Table 1 gives the results of the first 

 part, the study of variation in individual cows. The data com- 

 prise eight trials in which the mixed milk from different groups of 

 cows, as indicated by their herd numbers, was plated as one 

 sample. The cows were arranged in groups to introduce organ- 



TABLE2 

 Groicth of bacteria in milk, raw and inoculated with Bad. coli, at 87°C. 



* I = Innumerable. 



isms foreign to each cow's milk into each sample — which proved 

 to be essential in these cases for germicidal action — and to show 

 by elimination which cows possessed the germicidal property. 

 Only three of the eight samples (columns 1, 2, and 3) show a 

 decrease in bacteria distinct enough to be attributed to a germi- 

 cidal action; the others show only an increase in growth, or a 

 variation within the limits of experimental error. The samples 

 of milk which show a germicidal action (columns 1, 2, and 3) 

 are from six cows, numbers 134, 155, 188, 190, 196, and 212. 



