VIBRIO METCHNIKOVI. 355 



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 addition 

 of sulphuric acid alone. The production of indol by 

 this organism is usually greater than that common to 

 the comma bacillus under the same circumstances. 



In milk it causes an acid reaction with coagulation 

 of the casein. The coagulated casein collects at the 

 bottom 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 by the end of 

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

 decolorization and coagulation occurs. 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 rosolic-acid-peptone solu- 

 tion to become very much deeper after four or five days 

 at 37° C. 



It does not cause fermentation of glucose with pro- 

 duction of gas. 



It is killed in five minutes by a temperature of 50° 

 C. (Sternberg.) 



It is pathogenic for chickens, pigeons, and guinea- 

 pigs. Rabbits and mice are affected only by very large 

 doses. 



Chickens affected with the choleraic gastro-enteritis, 

 of which this organism is the cause, are ususlly seen 

 sitting quietly about with ruffled feathers. They are 



