10 BACTERIOLOGY. 



buboes, thence they extend into the lymphatic 

 glands and shortly before death are found in 

 rare instances and in small numbers in the 

 blood. Subcutaneous inoculation of rats, mice 

 and rabbits, causes these animals to sicken with 

 formation of buboes ; J;he animals also succumb 

 to stomach infection with virulent ctiltures 

 taken directly from man. An epidemic among 

 rats preceded the epidemic of the plague in that 

 quarter of Hong Kong lately visited by the 

 scourge ; buffalo and swine also sickened sim- 

 ultaneously. The question of the mode of 

 transmission of the disease is still obscure; 

 one well-supported possibility is that of the 

 conveyance of contagion by flies. 



" Mouse typhoid " is, according to LofHer, 1 

 caused by an anaerobic, arthrosporous bacter- 

 ium which grows slowly beneath the surface of 

 gelatin. In the interior of the gelatin it de- 



Spore formation has not been observed. Under favorable con- 

 ditions of moisture, temperature, etc., the plague bacillus may 

 survive for a long time outside of the animal body. (For a good 

 description of the characters of this bacillus cf. Abel, Zur Kennt- 

 niss des Pestbacillus, Centralbl. f. Bakt., XXL, 1897, p. 497, and the 

 paper of Ogata cited above.) 



Rats, mice, guinea-pigs and rabbits are susceptible and manifest 

 symptoms closely resembling those of the bubonic plague in man. 

 Animals such as rats are naturally infected and probably play an 

 important part in the dissemination of infection. An anti-plague 

 serum has been prepared by Yersin and Calmette, and has been 

 used with distinct success in parts of China and India. E. O. ]. 



1 Centralbl. f. Bakt, XL, 1892, p. 130. 



