554 PATHOGENIC BACTERIA. 



found a bacillus that resembles that of Yersin, but not 

 that of Kitasato, and it is certain that the description of 

 Yersin is the more correct of the two. 



In the Japan Times, Tokio, Nov. 28, 1899, Kitasato 

 explains that his investigations being made upon cadavers 

 that were partly putrefied, he was led to believe that the 

 bacillus first invaded the blood. Later studies upon living 

 subjects showed him the error of this view and the cor- 

 rectness of Yersin's observation that the bacilli first mul- 

 tiply in the lymphatics. 



The studies of Kitasato and Yersin show that in blood 

 drawn from the finger-tips and in the softened contents 

 of the glands the bacillus may be demonstrable. 



When cultures are made from the blood or softened 

 contents of the buboes the bacillus may be obtained in 

 pure culture, and is found to develop upon artificial 

 culture-media. In bouillon a diffuse cloudiness results 

 from the growth, as observed by Kitasato, though in 

 Yersin's observations the culture more nearly resembled 

 erysipelas cocci, and contained zooglea attached to the 

 sides and at the bottom of the tube of nearly clear fluid. 



According to Haffkine, 1 when an inoculated bouillon 

 culture is allowed to stand perfectly at rest, on a solid 

 shelf or table, a characteristic appearance develops. In 

 from twenty-four to forty-eight hours, the liquid remain- 

 ing limpid, flakes appear underneath the surface, forming 

 little islands of growth, which in the next twenty-four 

 to forty-eight hours grow down into a long stalactite-like 

 jungle, the liquid always remaining clear. In four or 

 six days the islands are still more compact and solidified. 

 If the vessel be disturbed, the islands fall like snow and 

 are deposited at the bottom, leaving the liquid above 

 clear. 



Upon gelatin plates at 22 ° C. the colonies may be ob- 

 served in twenty-four hours by the naked eye. They are 

 pure white or yellowish-white, spherical in the deep gela- 

 tin, flat upon the surface, and are about the size of a 



1 Brit. Med. Jour., June 12, 1897, p. 1461. 



