QUALITATIVE ANALYSIS OF MARKET MILK. ROS 
Oe LrlAliyVE ANALYSIS OF BACTERIA IN 
MARKET MILK. 
BY H. W. CONN AND W. M. ESTEN. 
Acknowledgment is hereby made to the Rockefeller Insti- 
tute for Medical Research for financial aid which has made it 
possible to carry out the work of the following investigations. 
In a paper previously reported (An. Rep. Storrs Exp. Sta., 
1900) was described a method of study of the bacteria in milk, 
which gave from the direct reading of plate cultures not only 
the numbers of bacteria present in each sample, but, at least 
approximately, the number and percentage of the different 
species. Qualitative analysis of bacteria in milk has rarely 
been attempted, but the lessons which are to be obtained from 
such a study are extremely important in their bearing upon | 
the general questions of milk bacteria related to both dairy and 
sanitary problems. ‘The experiments reported in the present 
article are a continuation of those previously described. 
The first series of experiments here described consisted of 
exaininations of the milk brought to market by the milkmen 
of the city of Middletown. The purposes of the experiments 
_ may be briefly outlined as three. 
1. To determine whether a qualitative analysis of market 
milk is possible, and whether such analysis is likely to give us , 
useful data concerning the relation of bacteria to milk products. 
2. To determine how great a variety of bacteria is shown 
by ordinary market milk. 
3. ‘To determine how great a variation there is in the species 
of bacteria present in the fresh milk of different dealers. 
METHOD OF ANALYSIS. 
The method adopted in this series of experiments is identical 
with that heretofore used and need not be described again here. 
