3 
48 STORRS AGRICULTURAL EXPERIMENT STATION. 
solution was neutralized so that it was slightly acid to phe- 
nolthphaline. Into this blue gelatine a small amount of diluted 
souring milk was inoculated, in the usual manner. After 
three or four days small red spots appeared where the acid bac- 
teria developed. ‘This simplifies the work very much, since 
the acid and alkaline organisms are differentiated at once. All 
of the culture media were prepared with three per cent. of 
milk sugar. 
Fresh milk was allowed to Stel until it commenced to 
curdle. At this stage there would be more of the typical acid 
organisms than at any previous or subsequent time in the 
changes of the milk. The dilutions were made with a platinum 
loop full of milk in five centimeters of sterile water. Those 
plates in which liquefiers were present prevented the discovery 
of the slow-growing acid organisms. When but a few or no 
liquefiers were present, in three or four days there would 
appear below the surface bright red spots, which showed very 
clearly in the surrounding blue. Not many acid colonies grew 
on the surface of the gelatine. She most abundant on the 
surface were moulds, yeasts, neutral and alkaline bacteria. 
The first sample of milk from one dairy had nearly a pure cul- 
ture of an alkaline liquefier, although the milk was acid in 
reaction. ‘The next sample from the same place, collected two 
weeks later, had not a single liquefier, but a nearly pure cul- 
ture of one organism, which appears to be the one so commonly 
present in nearly all the samples, and agrees so closely with the 
one isolated by Gtinther and ‘Thierfelder that it is called 
Bacillus acidi lactict of Hueppe. 
PHYSIOLOGICAL AND MORPHOLOGICAL CHARACTERS OF BACIL- 
LUS ACIDI LACTICI AS FOUND IN MILK IN 
THE UNITED STATHES. 
I.— BLUE LITMUS GELATINE. 
It requires from two to three days to develop a typical colony. 
Under a low power of the microscope, one inch objective, a 
small colony appears, surrounded by an intense red halo. 
The colony appears to be covered with short stumpy spines, 
which give it the appearance of a chestnut burr, and from 
which it has been named the burr colony. Under a high power 
these spines are found to be granular processes which extend 

