296 BACTERIA AND DISEASE 



Hewlett and Knight,* Eichmond and Salter,f Ohlmacher,J and others). 

 Evidence in support of the view that Hermann's bacillus is an 

 attenuated variety of the true diphtheria bacillus has been brought 

 forward. But it can only be accepted provisionally. Graham-Smith, 

 Thomas and others consider the pseudo-bacillus to be absolutely 

 innocuous. In practice, it is the right course at present to look upon 

 the presence of the Hof mann bacillus as indicating a suspicious throat. 

 It should not be forgotten that there are a number of other bacilli 

 from which the true diphtheria bacillus must be differentiated.! These 

 include the B. coryzce segmentosus, the bacillus of Hofmann, B. xerosis, 

 and a number of diphtheroid bacilli, and organisms from nasal and 

 aural discharge. Similar organisms occur in birds and other animals. 

 There are, as summarised by Gordon, five chief characters by which 

 the true diphtheria bacillus may be known: (a) The macroscopic 

 and microscopic appearance of the growth on blood serum; (5) the 

 behaviour of the bacillus to Loffler's blue, Gram's stain, and Neisser's 

 stain for granules ; (c) the reaction to litmus of a culture in alkaline 

 broth, containing 2 per cent, of dextrose after 48 hours at 37 C. ; 



(d) the pathogenic test 1 c.c. of broth culture, 48 hours' growth at 

 37 C., injected subcutaneously into 200-300 gramme guinea-pig, pro- 

 duces death generally in 48 hours, whilst post-mortem heemorrhagic 

 necrosis and oedema are found locally, the internal organs are con- 

 gested, the pleural, pericardial, and peritoneal fluids are increased, 

 and the supra-renal capsules are enlarged and engorged with blood ; 



(e) the virulence of the organism or its toxin is completely neutralised 

 by a simultaneous dose of diphtheria antitoxin. For purposes of rapid 

 diagnosis, (a) and () are relied upon. 



Scarlet Fever 



That the essential cause of scarlet fever is a micro-organism there 

 can be little doubt. But up to the present time no organism has 

 been definitely isolated which fulfils the postulates of Koch in respect 

 to specificity of bacteria. Various organisms have, however, been 

 described as associated with the disease. Edington, Frankel, Freud- 

 enberg, Klein, Kurth, Gordon, Baginsky, Class, and others have 

 described organisms which they believed to be etiologically related to 

 the disease. At present, however, it can only be said that these 

 bacteria have been found associated with scarlet fever, but are not yet 

 proved to be its cause. The organism which appears at present to be 



* Trans. .Tenner Inst. Prevent. Med. (First Series), 1897, p. 7 et seq. 

 f Guy's Hospital Report, 1898, vol. liii., p. 55. 

 j Jour, of Med. Research, 1902, vol. ii., p. 128. 



Rep. of Local Govt. Board, 1901-02, pp. 418-39 (Gordon); Jour, of /%., 1904, 

 pp. 299-316. 



