DESCRIPTIONS OF PATHOGENIC BACTERIA. 195 



to the colon bacillus. A. Gartner T has isolated 

 a species which has frequently been found in 

 cases of poisoning from meat, sausage and 

 milk. In cultures, however, after about two 

 transfers, a difference in the behavior toward 

 stains makes its appearance. The colon bac- 

 terium generally shows polar granules, but in 

 Gartner's bacterium, after staining with gen- 

 tian-violet and decoloration with 2 per cent, 

 acetic acid, the middle portion remains colored. 

 In the epidemic of bubonic plague occur- 

 ring in China, in 1894, bacteria were found by 

 Yersin and Kitasato which occur in the form of 

 cocci and short rodlets, and belong therefore to 

 the genus Arthrobacterium. The character- 

 istic growth of the microbes upon agar and 

 gelatin has not been communicated up to this 

 time. 2 In man they are found at first in the 



1 Correspondenz-Blatt d. allg. arztl. Ver. von Thiiringen, 1888, 

 No. 9. 



2 There seems still to be some uncertainty respecting the identity 

 of the germs originally described by Kitasato and Yersin. (Ogata, 

 Centralbl. f. Bakt, XXI., 1897, p. 769). The plague bacillus that 

 has found its way to bacteriological laboratories and with which 

 successful inoculation experiments have been made has well-defined 

 characters. It is rod-shaped, and is about i/z in diameter, though 

 varying considerably in length and exhibiting marked pleomorphism. 

 It is wholly without the power of independent movement. It stains 

 easily with the ordinary aniline dyes, but is decolorized by Gram's 

 method. Growth occurs readily on the ordinary nutrient media. 

 On agar, white circular colonies, somewhat transparent and with 

 iridescent edges, are formed. The germ multiplies best at about the 

 temperature of the human body, though it also grows at 8-io 



