80 STORRS AGRICULTURAL EXPERIMENT STATION 
found in a sample of freshly drawn milk is an indication of 
the amount of external contamination which the milk has 
received. The numbers of bacteria contained in the different 
samples of milk is, therefore, used as a basis for determining 
the relative amount of dirt and dust which fell into the milk 
during its production. In order to determine the germ con- 
tent each sample of milk was plated while fresh into litmus 
sugar gelatin and these plates were then allowed to develop 
at a constant temperature of 70 F. for six days. At the end 
of this time the colonies were sufficiently developed so that a 
satisfactory study of the plates could be made. In.studying 
the plates the total number of bacteria, the number of acid 
producing species and the number of liquefying species were 
determined and also the principal species which the milk con- 
tained. The total number of bacteria contained by any sam- 
ple is of importance as being an indication of the total dirt 
contamination which the milk has received. The acid organ- 
isms are of importance since it is the action of this group of 
bacteria which causes the souring of milk and the number of 
liquefying bacteria is of considerable significance because they 
indicate the source from which the dirt contamination has 
come, these species being commonly found in filth and putre- 
factive materials. In certain cases sub-samples were taken 
from the fresh milk and kept at a constant temperature to 
determine the keeping quality of the milk and the results ob- 
tained from these tests are given in connection with some 
of the experiments. Certain special methods employed in 
connection with the different groups of experiments will be 
discussed in connection with those tests. 
EFFICIENCY OF A COVERED. PAIL IN. A: WELL, KEPT STABLE. 
Table No. 18 gives the results of a series of tests in the Col- 
lege stable where the conditions of cleanliness are some- 
what above those usually found in dairy barns. The stable 
itself is in the basement and far from ideal in location and 
construction but considerable care is taken to keep the stable 
and the cows clean. A photograph of the stable is given in 
the frontispiece. The Stadtmueller pail used in these tests can 
be seen in this picture. 
A 
