64 



Kansas Academy of Science. 

 Table III. 



* The apparent discrepancy between the number of organisms in mixed milk and the 

 number in skim milk plus cream may be explained by the unequal volumes of skim milk 

 and cream. The entire voluine of cream obtained from a single sample of milk is much 

 smaller than the entire volume of skim milk, but we took the same volume (1 cc.) from 

 each as a sample. WHien these are mixed the number in the cream is reduced, while the 

 number in the skim milk is increased, but in unequal proportion. So that the number 

 given for mixed milk is not a sum of the two numbers given for skim milk and cream, but 

 is that which we actually obtained by count. 



As in the former case, the mixed milk (after separating) 

 contained nearly double the number found in the whole milk. 

 In the first series there were larger numbers of organisms in 

 the skim milk, but in the second series there was a marked in- 

 crease in the numbers in the cream. These results are similar 

 to those of various investigators of this problem, since some 

 found more in the milk and others more in the cream. 



Attempts were made to determine the cause of such discrep- 

 ancies. Samples were taken from the spout of the separator 

 at different intervals during the process of running the same 

 sample of milk. Only two series of such tests were made, but 

 these are sufficient to denote the great irregularity of the dis- 

 tribution of bacteria in the same sample, and indicates that 

 testing at different times might account for the results of vari- 

 ous investigators. Table IV shows the result. 



Table IV. 



The influence of different separators as regards the distri- 

 bution of microorganisms is found in Table V. Six different 

 machines were used and are referred to by number. The 

 figures are an average of several trials. 



