TRANSMISSION TO ANIMALS. 485 



of infected material or by placing it on the nasal 

 mucous membrane or in the conjunctival sac, and by 

 inhalation experiments, the last method commonly 

 resulting in plague pneumonia. Guinea-pigs and 

 young rabbits die of plague septicemia in from 

 four to live days when cultures or material con- 

 taining the organisms (sputum, feces, organs from 

 plague cases), are rubbed into the shaven or even 

 unshaven skin (Albrecht and Ghon). This experi- 

 ment is of value for detecting virulent plague ba- 

 cilli and separating them from contaminating or- 

 ganisms. Following inoculation into a cutaneous 

 or mucous surface a local reaction of varying in- 

 tensity develops in which the subcutaneous tissue 

 becomes edematous or even hemorrhagic, in a num- 

 ber of hours the regional lymph glands become 

 swollen and hemorrhagic, and in from two to five 

 days the animals die of plague septicemia. Cul- 

 tures of low virulence not infrequently cause a 

 chronic infection which is characterized by the for- 

 mation of large granulomatous nodules on the sur- 

 face of the liver and spleen and in the omentum. 

 Such foci contain many plague bacilli, and the 

 death of the animal results in a few weeks from 

 intoxication or from general infection. Although 

 rabbits are much less susceptible than rats or 

 guinea-pigs, young animals succumb to cutaneous 

 inoculation. 



Dieudonne cites four foci in which plague is Endemic 

 known to be endemic at the present time : One is plagrue * 

 in China (province of Yunnan), from which the 

 Hongkong epidemic originated; a second in the 

 Himalayas, which led to the outbreak in Bombay; 

 a third in a mountainous region south of Mecca, 

 and a fourth was found by Koch and Zupitza in 



