SYSTEMATIC AND DESCRIPTIVE. 175 



fever). Rods, '2 //. broad, and forming filaments 

 up to 50 jji long ;* orf rods, short, rounded at their 

 ends, and occasionally constricted in the middle ; 

 some exhibiting spore formation. These bacilli 

 have been observed in inflamed Peyer's glands, in 

 the spleen, mesenteric glands, and the lungs in 

 fatal cases of typhoid fever. More recently J a 

 bacillus has been cultivated on several plates of gela- 

 tine which were inoculated from different spleens. 

 After twenty-four hours the course of the inoculation 

 streak became visible, and in forty-eight hours a 

 distinct whitish growth had developed. With a low 

 power this was found to consist of numerous colonies 

 of a yellow-brownish colour. The gelatine was not 

 liquefied. The rods varied in length, were capable 

 of development into threads, and both forms were 

 motile. They can be cultivated on potatoes at 

 37 C. They grow well also on blood serum, form- 

 ing a whitish-grey, somewhat transparent layer. 

 Spore formation occurs at the ends of the rods. 

 Inoculation experiments gave negative results. 



METHODS OF STAINING THE BACILLUS OF TYPHOID 

 FEVER. 



The bacilli stain badly with most aniline dyes. The 

 method of Gram can be employed, or the sections may be 

 left for twenty-four hours in methylene-blue. Koch re- 

 commends bismarck-brown. To colour the spores cover- 

 glass preparations and sections must be left for several 



* KleVsArcA.f. Experimental Pathol. 1880. 



t Eberth, Vzr chow's Archiv, Bd. 83. 



t Gaffky, Mittheil a. d. K. Gesundheitsamte. 1884. 



