508 BACTERIOLOGY, 



twenty-four hours at the body temperature. Its reac- 

 tion becomes more alkaline as growth progresses. A 

 pellicle, at first delicate, later denser always character- 

 izes the growth in this medium. 



POTATO. Usually no visible growth. 



LITMUS MILK. In fresh litmus milk a slight degree 

 of acidity is noticed after twenty-four hours at body 

 temperature. After forty-eight hours this acidity is 

 slightly greater, and at times the milk shows evidences 

 of coagulation, though not always. 



BIOCHEMIC CHARACTERS. Microspira Schuylkilli- 

 ensis is an aerobic, facultative organism. In fluid media 

 under an atmosphere of carbon dioxide in sealed tubes 

 no growth is observed. 



The organism grows most luxuriantly at about 37.5 

 C. Growth is hardly perceptible at 10 C. It is 

 destroyed by an exposure of five minutes to 50 C. 



None of the carbohydrates are broken up with the 

 liberation of gas. 



It produces indol and at the same time reduces 

 nitrates to nitrites. 



PATHOGENESIS. The pathogenic properties of this 

 organism are best seen in guinea-pigs and pigeons, both 

 of which are uniformly susceptible. Rabbits and 

 chickens resist relatively large doses. Mice are infected 

 with small doses injected subcutaneously. 



The most characteristic lesions follow the injection of 

 cultures into the pectoral muscles of pigeons. At death 

 the inoculated muscle is swollen, necrotic, and the over- 

 lying tissues are oedematous. The bacteria are found in 

 large numbers in the vicinity of the seat of the inocu- 

 lation, and in relatively small numbers in the blood and 

 internal organs. 



