THE HOFMANN BACILLUS 291 



bacillus. The writer, 1 Cobbett, 2 Petrie, 3 Williams, 4 and 

 Clark 5 have, however, quite failed to confirm Salter's 

 results. Thiele and Embleton also claim to have effected 

 the transformation of a typical Hofmann bacillus into a 

 virulent Klebs-Loffler bacillus by massive intra-peritoneal 

 inoculation of guinea-pigs with Hofmann culture suspended 

 in 30 per cent, gelatin and after death of the guinea-pig, 

 injection of the peritoneal exudate with a smaller amount 

 of living bacilli into a second guinea-pig, and repeating 

 this method of inoculation. Finally the bacillus became 

 Klebs-Loffler in morphology and 1 c.c. of its toxin killed a 

 guinea-pig in forty-eight hours, and this toxin was 

 neutralised by diphtheria antitoxin. 



To sum up : the Klebs-Loffler-like avirulent bacilli met 

 with in the throat, the pseudo-diphtheria bacilli of Roux 

 and Yersin, are probably modified and avirulent diphtheria 

 bacilli. As regards the Hofmann bacillus, the general 

 trend of opinion at present is to consider it as quite distinct 

 from the Klebs-Loffler bacillus. Another view is to regard 

 it as in reality including several species, of which one 

 may be a modified Klebs-Loffler bacillus, the others having 

 no relation with this organism. The Klebs-Loffler-like 

 avirulent bacilli might, therefore, be regarded as true 

 diphtheria bacilli slightly removed from virulence, the 

 Hofmann bacillus, if derived from the Klebs-Loffler, as a 

 diphtheria bacillus far removed from virulence. 



In determining the fermentation reactions of the diphtheria-like 

 bacilli, the organisms should first be grown in broth until they 

 become acclimatised to this medium, or should be grown in a 

 medium which suits them, e.g. broth with the addition of serum or 

 of ascitic fluid. Hiss's serum- water medium is satisfactory serum 



1 Brit. Med. Journ., Sup., July 9, 1904. 



2 Journ. of State Med., vol. xi, p. 609. 



3 Journ. of Hygiene, vol. v, p. 134. 



* Journ. Med. Research, 1902, p. 83. 



5 Journ. Infect. Diseases, vol. vii, 1910, p. 335. 



