SYSTEMATIC AND DESCKJFHVE,K II MT1 2 



gelatine which were inoculated 

 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 



FIG. 103. BACILLUS TYPHOSUS FROM A POTATO-CULTIVATION, x 1500. 



(Fig. 103), were capable of development into threads, 

 and were motile. They can be cultivated on potatoes 

 at 37 C. They grow well also on blood serum, 

 forming a whitish-grey, somewhat transparent layer. 

 Spore-formation occurs at the ends of the rods. It 

 is stated that inoculation experiments have been 

 made in some cases with success.* 



METHODS OF STAINING THE BACILLUS OF TYPHOID 



FEVER. 



To stain the bacilli in the tissues the method of Gram 

 can be employed, or the sections may be left for twenty- 

 four hours in methylene-blue. Koch recommends bis- 

 marck-brown. To colour the spores cover-glass preparations 

 and sections must be left for several days in the fuchsine 

 solution employed in the method of Ehrlich (p. 163) ; or 

 the solution may be warmed, and in the case of cover- 

 glasses, even raised to boiling-point. They are then 

 decolorised with nitric acid, and after-stained with 

 methylene blue. 



* Frsenkel and Simmonds, Die Atiolog. bedeutung des Typhus - 

 bacillus. 1886. 



