304 BACTERIOLOGY. 



It grows at temperatures ranging from 22 C. to 

 37 C., but most luxuriantly at the latter temperature. 



Its growth in the presence of oxygen is more active 

 than when this gas is excluded. 



STAINING. In cover-slip preparations made either 

 from the fauces of a diphtheritic patient or from a pure 

 culture of the organism, it is seen to stain readily with 

 the ordinary aniline dyes. It stains also by the method 

 of Gram, but the best results are those obtained by the 

 use of Lreffler's alkaline methylene-blue solution ; this 

 brings out the dark points in the protoplasmic body of 

 the bacilli and thus aids in their identification. 



For the purpose of demonstrating the Loeffler bacillus 

 in sections of diphtheritic membrane, both the Gram 

 method and the fibrin method of Weigert give excellent 

 results. 



PATHOGENIC PKOPERTIES. When inoculated sub- 

 cutaneously into the bodies of susceptible animals tl:e 

 result is not the production of septicaemia, as is seen to 

 follow the introduction into animals of certain other 

 organisms with which we shall have to deal, but the 

 bacillus of diphtheria remains localized at the point of 

 inoculation, rarely disseminating further than the near- 

 est lymphatic glands. It develops at the point in the 

 tissues at which it is deposited, and during its develop- 

 ment gives rise to changes in the tissues which result 

 entirely from the absorption of poisonous albumins 

 produced by the bacilli in the course of their develop- 

 ment. 



1 Frosch: Die Verbreitung des Diphtheric-bacillus im Korper des Menschen. 

 Zeit. fur Hygiene und Infectionskrankheiten, 1893, Bd. xiii. p. 49-52. Booker : 

 Archives of Pediatrics, Aug. 1893 ; Wright and Stokes : Boston Med. and Surg. 

 Journ., March and April, 1895. 



