368 VETERINARY BACTERIOLOGY 



single terminal flagellum, and is about 0.5 by 2 p. Neither capsules 

 nor spores are produced. It stains readily, but is gram-negative. 



Isolation and Culture. The organism may be isolated from the 

 intestinal contents of adult fowls and from the blood of younger 

 fowls by plate cultures in nutrient gelatin. Upon these plates 

 small white, punctiform colonies are developed in the course of 

 twelve to sixteen hours; these enlarge rapidly, cause liquefaction 

 of the gelatin, and are soon to be found in saucer-shaped depressions 

 in the medium. Growth in a stab culture in gelatin is likewise 

 rapid, and the gelatin is quickly liquefied in the form of a funnel. 

 Upon agar slants a yellowish layer is developed. Bouillon is 



Fig. 156. Spirillum metchnikovi in the blood of a pigeon ( X 1000) (Frankel 



and Pfeiffer). 



clouded, and a delicate pellicle may form. Milk is coagulated 

 with acid reaction and without solution of the casein. 



Physiology. The organism is aerobic. It develops almost as 

 rapidly at room-temperature as at blood-heat. The thermal 

 death-point is 50 for five minutes. It is sensitive to the pres- 

 ence of acids in culture-media, and soon dies in consequence of 

 their production in milk. It produces acid from dextrose and 

 lactose, but no gas. Indol is formed. Gelatinase is developed, 

 but no enzyme which will digest casein. 



Pathogenesis. Experimental Evidence. Subcutaneous inocu- 

 lations into the chicken, pigeon, and guinea-pi^ ;iro quickly fatal; 

 rabbits and mice succumb only to large doses. The disease ap- 



