80 STORRS AGRICULTURAL EXPERIMENT STATION. 
The explanation of this unusual series of tests seems to be in 
the peculiarities of this No. 249, which is capable of growing 
prodigiously in milk at low temperatures, if unhindered by 
other species. ‘The lactic bacteria develop so slowly. at 10° 
that it was not until after 300 hours that the amount of acid 
developed became sufficient to check the exceptional develop- 
ment of No. 249; but from this time on they were overpowered 
by the developing acid, and dropped down in the end to a 
comparatively small number. 
Milk kept at 20°.—At this temperature the Group IV. con- 
stantly increased in numbers until, at 48 hours, there were over 
4,500,000,000 per cubic centimeter. At thesame time there were 
I,700,000,000 of the lactic Group I. and small numbers of other 
species. ‘his experiment shows, therefore, that the 20° tem- 
perature stimulates the development of the lactic bacteria of 
Group I., as it has in all other cases, but that the milk does not 
curdle so quickly as usual. In most cases the milk curdles when 
the number of bacteria is from 500,000,000 to I,000,000,000 per 
cubic centimeter, but in this experiment it did not curdle until 
it reached nearly 2,000,000,000. ‘The explanation of this fact 
seems to be due to the large numbers of Group IV., which 
neutralized to a certain extent the acid developed by Group I. 
It will also be noticed that, with the exception of a small per- 
centage of liquefiers, all other bacteria disappeared from the 
milk, except the two groups of acids and the neutral Group 
IV. In other words, this experiment resembles those previ- 
ously described at 20°,. with the exception of the enormous 
development of this No. 249, which modifies the results. 
The general result of this experiment may be stated, briefly 
as follows: ‘This sample of milk apparently contained a species 
of bacterium which was particularly adapted to grow at low 
temperatures. The result was that the sample of milk kept at 
1o° and at 1° became filled with bacteria to an extent not 
found in any other sample of milk ever studied in our labora- 
tory. The development of this species seemed for a time to 
check the development of all others; but in the end the lactic 
bacteria gradually overcame this species, No. 249, as well as all 
others, and in the final tests the acid organisms were about as 
