36 STORRS AGRICULTURAL EXPERIMENT STATION. 
that the straining has a tendency to remove a relatively larger 
number of lactic bacteria. The difference, however, is only 2 
per cent. and is probably not large enough to have any sig- 
nificance. 
5. The comparison of the amounts of acid present in the 
samples after 50 hours shows that, in general, the develop- 
ment of acid is parallel with the number of bacteria. ‘The 
samples having the largest amount of acid at 50 hours have 
large total numbers of bacteria, while those that have small 
amounts of acid have small numbers of bacteria. While this 
parallel is apparent, it is not very close, and noticeable irregu- 
larities appear. 
6. ‘The number of bacteria present at the end of 50 hours 
seems to be totally independent of the number present at the 
outset. If experiment No. 4 be compared with experiments 
No. 3, this will be seen. In the first experiment the number 
of bacteria present at the outset was 1,625, and the number 
present in 50 hours was 1,800,000,000; on the other hand, in 
experiments No. 3 the numbers at the outset were 8,o00 and 
9,000 respectively, while at the end of 50 hours there were 
only 24,000,000 and 38,000,000 bacteria found. In experi- 
ment No. 9 it will be seen that the milk at the outset contained 
44,000 bacteria, next to the largest of any of the tests, while 
at the end of 50 hours the number was 338,000,000, only about 
one-sixth as many as in experiment No. 4, which at the outset 
had only 1,600 bacteria. A further examination of the figures 
in the two columns will show that no relation can be established 
between the number of bacteria in the fresh milk and the 
number present at the end of 50 hours. This fact is very sur- 
prising, considering that the milk was kept under identical 
conditions. 
7. The milk kept for 50 hours always contained high per- 
centages of lactic bacteria, as shown by the table. The per- 
centage of lactic bacteria was usually from 90 to 100 per cent., 
although in one case it dropped to 50 per cent. ‘The percentage 
of lactic bacteria in the fresh milk in all cases was far lower 
than this, ranging from 9 per cent. to 53 per cent. in individual 
cases. 




