74. STORRS AGRICULTURAL EXPERIMENT STATION. 
milk were placed in sterile tubes, plugged with cotton imme- 
diately, and set aside at 20° C. At the end of two days a 
typical curdling had taken place in every tube, and an exam- 
ination of the milk showed the universal presence of B. aczdz 
lactic? ’The only conclusion that could be drawn from these 
experiments was, then, that the B. acidi lactict does not come 
from. the milk duct, but is a secondary contamination of the 
milk from the outside, and, therefore, that if sufficient care is 
taken, milk can be drawn without being contaminated with 
lactic bacteria. 
Up to this point, then, experiments have warranted the fol- 
lowing conclusions: 
1. Milk when first drawn may contain many liquefying and 
miscellaneous bacteria with but few or no acid organisms. 
2. ‘The acid organisms are probably an outside contamina- 
tion. 
3. ‘These acid organisms, though few at first, rapidly mul- 
tiply in the milk, soon checking the growth of the liquefiers 
and miscellaneous bacteria. 
4. Unripened cream or sweet milk contains from 50,000 to 
2,000,000 bacteria per cubic centimeter, but this number in- . 
creases rapidly for 24 hours and finally reaches several hundred 
millions. 7 
5. Ripened cream has bacteria varying from 55 million to a 
billion and a half or more in each cubic centimeter, and of this 
large number commonly over 90 per cent. are B. acidz lactict, 
although this species is absent in freshly drawn milk and 
present only in very small numbers in sweet milk. 
SECOND SERIES OF EXPERIMENTS. 
At this point the experiments were interrupted; but a year 
later, in the spring of 1901, they were resumed for the purpose 
of more strictly demonstrating the previous conclusions and 
also determining by fosztive evidence, if possible, the source of 
the widespread B. actdi lactict. 
Experiment No. rz.—This experiment was merely a repe- 
tition of three of those in the first series. It consisted in 
drawing milk from a large number of cows into sterile vials, 
only such cows being chosen as could be milked with the 


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