484 BACTERIOLOGY. 



to forty-eight hours a grayish deposit appears, which has 

 a tendency to become yellowish with age. 



On potato at 37 C. its growth is seen as a moist, 

 coffee-colored patch, surrounded by a much paler zone. 

 The whole growth is so smooth and glistening that it 

 has somewhat the appearance of being varnished. 



In bouillon it quickly causes opacity, with the ulti- 

 mate production of a delicate pellicle upon the surface. 



It causes liquefaction of blood-serum, the liquefied 

 area being covered by a dense, wrinkled pellicle. 



When grown in peptone solution it produces indol 

 and coincidently nitrites, so that the rose-colored reac- 

 tion characteristic of indol is obtained by the addi- 

 tion of sulphuric acid alone. The production of indol 

 by this organism is usually greater than that com- 

 mon to the comma bacillus under the same circum- 

 stances. 



In milk it causes an acid reaction with coagulation of 

 the casein. The coagulated casein collects at the bot- 

 tom of the tube in irregular masses, above which is a 

 layer of clear whey. If blue litmus has been added 

 to the milk, the color is changed to pink in from 

 twenty-four to thirty hours, and after forty-eight hours 

 decolorization and coagulation occur. The clots of 

 casein are not re-dissolved. After about a week the 

 acidity of the milk is at its maximum, and the organ- 

 isms quickly die. 



It causes the red color of the rosolic-acid-peptone 

 solution to become very much deeper after four or five 

 days at 37 C. 



It does not cause fermentation of glucose with pnx 

 duction of gas. 



