P 2, STORRS AGRICULTURAL EXPERIMENT STATION. 
peculiar source of contamination. In the following tables it 
did not seem feasible to tabulate each of these accidental spe- 
cies separately, and they are therefore grouped together in the 
column Miscellaneous. This group, therefore, includes easily 
differentiated bacteria, sometimes a single species and some- 
times several. In experiment with No. 8 in June as many as 
eight species are here included. The work of classifying all 
these species has not yet been completed. 
Group XII. Undetermined. This column is simply the 
expression of the incompleteness of the differentiation. After 
counting all the colonies which were capable of recognition as 
belonging to the various groups, the numbers of the different 
recognizable species were added together and subtracted from 
the total number of colonies, the difference giving the number 
of undetermined. This column indicates therefore the number 
of colonies that were not characteristic enough to determine 
accurately. Nearly all of them would be placed in Groups I., 
II., and IV., if the differentiation had been complete. The 
larger the proportion of liquefiers, as a rule, the larger this 
column of undetermined. . 
REPORTS OF ANALYSES. 
From the analyses of milk from the milkmen of Middletown 
we have selected 27 experiments, the results of which are given 
in the following table. In this table the number of bacteria 
per cubic centimeter is given first, and below is the percentage 
of each group detected. ‘The numbers represent the average 
of all plates made, half of which contained-milk diluted 100 
times and half 600 times; and since the dilution of 600 always 
gave higher numbers than that of roo times, the figures given 
are smaller than the actual numbers. 


ee a ae ee ae EP 
a ie 
* 
