1 82 BACTERIOLOGY. 



identity must be regarded as still an open one. 

 Symptomatic anthrax was formerly regarded 

 as a form of anthrax till Feser and Bollinger 

 determined its true specific nature in 1876 ; 

 Arloing, Cornevin, and Thomas were the first 

 to obtain cultures. 



In diphtheria, rods were first observed mi- 

 croscopically by Klebs, and in 1884 Lo filer 

 succeeded in cultivating them on artificial 

 media. The rods take stain badly and are 

 easily plasmolyzed, so that usually the ends of 

 the rods stain more plainly than the middle, or, 

 sometimes, the staining of a number of gran- 

 ules gives a beaded appearance to the cell. 

 The bacteria retain the stain when treated by 

 Gram's method. The rods are localized in the 

 diphtheritic patches upon mucous membranes 

 and are not dispersed through the body. The 

 effect produced by their presence upon the 

 animal organism is therefore due to the forma- 

 tion of poison. The poison was at first re- 

 garded by Roux and Yersin as an enzyme, 

 and by Brieger and Frankel as a toxalbumin ; 

 it is formed in media containing proteid and also 

 in solutions devoid of proteid, as in ammonium 

 lactate or asparagin (Uschinsky), and in pro- 

 teid-free urine (Guinochet) ; and even after the 

 formation of the toxin, no proteid reaction is ob- 

 tained from these media ; the proteid nature of 



