78 STORRS AGRICULTURAL EXPERIMENT STATION. 
it rendered the milk alkaline, and it developed in most extra- 
ordinary numbers in all three samples of milk, particularly in 
those kept at low temperatures. The numbers increased in the 
10° milk to 200,000,000,000 per cubic centimeter, a number never 
before found by us in any sample of milk studied. The enor- 
mous development of this species of bacteria rendered the 
results quite different from those of other experiments, and 
made worthless quite a large number of the plates kept at 10°. 
The dilutions which we adopted were those which experience 
has shown us to be proper for an ordinary development, but 
were entirely too low for samples of milk where this particular 
species developed in such very great numbers. 
Milk kept at r°.—1. ‘Tests were made at intervals of 3 or 4 
days for a period of 42 days, as shown in Table 22. ‘The most 
noticeable feature was the development of the Group IV., which 
contained, at first, two species, Nos. 194 and 249. ‘The No. 
194 appeared to be abundant at the start, but after a while it 
was replaced by No. 249, and, apparently, at the close of the 
test No. 249 was the only one remaining alive in the milk. It 
was impossible to differentiate the two in our counting of the 
colonies on the plates, hence we cannot say positively that the 
194 had completely disappeared; but most of the colonies present 
at the end were of species 249. | 
2. Hor 6 days there was no increase in numbers, and in- 
deed, the number present on the 6th day was less than at the 
start. After the 6th day the numbers of the Group IV. began 
to increase rapidly, so rapidly and unexpectedly that the next 
two tests made were not diluted sufficiently to enable us to de- 
termine with any accuracy either numbers or species of bacteria. 
They are, therefore, omittted from the table. 
3. The milk did not curdle even after the 42nd day, 
although it became somewhat thick and acid. 
4. The number of bacteria became very high, although not 
so high asin the same milk keptat 10°. In 27 daysthere were 
about 1,700,000,000 bacteria per cubic centimeter, after which 
they were reduced in numbers. In 36 days the number of acid 
bacteria was 400,000,000, enough to have curdled the milk un- 
der ordinary conditions; but the enormous development of the 
