30 STORRS AGRICULTURAL EXPERIMENT STATION. 
bacteria is extremely small; indeed, so few of them are present 
that they can be found in only a small percentage of the 
samples of freshly drawn milk. In the cream which we have 
tested the numbers were at the outset always small, in some 
cases so few that we could not find them at all with the dilu- 
tions which we were obliged to use. In the different samples 
the proportion was quite variable, but always small. With the 
successive hours of ripening the number of the bacteria of this 
species increased with perfect regularity, until at the time when 
the number of organisms in the cream was at its maximum, 
the proportion of No. 206 had reached usually about 90 per 
cent. and sometimes more. ‘his, of course, meant enormous 
actual numbers, for 90 per cent. of the many millions found is 
a very large number. 
9. The B. lactis aerogenes has a peculiar relation to the 
ripening cream. It is always present in small proportions; it 
appears neither to increase nor to decrease with any regularity 
during the ripening, being usually found at the outset in small 
numbers and at the close of the ripening in similar small 
numbers. Although the percentage did not regularly increase 
or decrease, there was a constant slight increase in actual 
numbers. 
1o. The lactic bacterium No. 202 appears to be quite char- 
acteristic in these dairies. It was rarely found in fresh cream, 
doubtless because of its small numbers, made its appearance 
after a few hours, and in practically all cases began to increase 
somewhat after 36 to 48 hours, being commonly present in 
larger proportion at the close of the experiments than at the 
beginning. 
Ir. From these facts it will be seen that in old, well ripened 
cream we have a nearly pure culture of two species of lactic 
bacteria, No. 206 and No. 202. ‘The immense numbers given 
in the first column consisted commonly of over 98 per cent. 
of these species, the others being quite incidental. It is of 
course to be noted that the maximum numbers which we 
have obtained represent cream that was somewhat older than 
normally ripened cream, but practically the same facts are true 
of the normally ripened cream, as shown by the previous 
tables. 
