SO PSEUDOTUBERCULOSIS 



tection against infection. Sheep are supposed to acquire the infection 

 largely through feeding. 



As the disease is slowly progressive and most sheep are slaugh- 

 tered, the condition is usually not recognized during life. 



This variety of the bacillus is pathogenic, not only to sheep but, 

 experimentally at least, to goats, rabbits, guinea-pigs and mice, but not 

 to chickens and pigeons. A second variety of this organism is patho- 

 genic to mice, especially to gray mice. It is not known to be patho- 

 genic to any other animal. Bouillon cultures of this variety become 

 slightly cloudy and deposit abundant coffin-lid crystals (ammonio- 

 magnesium phosphate). 



A third variety seems to be pathogenic to many rodents and may 

 cause epidemics in rabbits and guinea-pigs. This produces crystals 

 in both gelatin and bouillon cultures and does not elaborate a soluble 

 toxin. A fourth variety infects children and several cases have been 

 reported by French physicians. The cat is suspected as a carrier. 



