New York Agricultural Experiment Station. 411 



litmus milk becomes just a shade lighter blue, but during the 

 following three weeks the blue color entirely disappears, leaving 

 the milk very nearly the color of normal milk and with no pre- 

 cipitation of the casein. The cause of this peculiar behavior of 

 litmus milk is not known to the writer. 



Peptone-rosolic-acid solution is prepared by adding to 100 cubic 

 centimeters of Dunham's peptone solution (see formula pre- 

 viously given), 4 cubic centimeters of the following solution: 

 Rosolic acid;, 0.5 grams; alcohol (80 per cent), 100 cubic centi- 

 meters. 



The litmus milk was prepared as follows: One cubic centi- 

 meter of a saturated aqueous solution of Trommsdorf s litmus 

 was put into a test-tube containing ten cubic centimeters of sweet 

 skimmed milk and the whole sterilized. After sterilization the 

 contents of the tube were of a pale blue color. It was tested 

 with malic acid and potassium hydrate and found to react prop- 

 erly. 



Growth on acid and alkaline media. — The organism appears to 

 grow best on neutral or slightly acid media. A comparatively 

 slight degree of alkalinity is sufficient to prevent growth wholly, 

 but on the acid side there is a wider range. It grew very feebly 

 on 10 c. c. of agar containing 0.05 c. c. of a saturated solution of 

 sodium carbonate. However, on agar containing 0.02 c. c. of a 

 saturated solution of sodium carbonate per 10 c. c. of agar it 

 grew readily and with the same color and habit of growth as on 

 neutral agar. In sterilization, the agar containing the larger 

 amount of sodium carbonate browned slightly. The tests with 

 acid media were made in bouillon acidified with malic acid. The 

 germ grew readily in bouillon containing as much as 1 c. c of a 

 1 per cent solution of malic acid per 10 c. c. of neutral bouillon. 

 When double this amount of malic acid was used no growth was 

 obtained. 



Gas production. — The organism does not produce gas by the 

 fermentation of grape sugar, cane sugar or milk sugar. Tubes 

 of neutral agar containing two per cent of these sugars were 

 inoculated, thoroughly shaken and cooled quickly. Numerous 

 amall colonies of the germ developed throughout the medium but 



