i 9 4 



PATHOGENIC BACTERIA. 



covered by Hansen, and subsequently clearly described 

 by Neisser. 



The bacillus is almost the same size as the tubercle 

 bacillus perhaps a little shorter but lacks the curve 

 which is so constant in the latter. It stains in very 

 much the same way as the tubercle bacillus, but permits 

 of a rather more rapid penetration of the stain, so that 



FIG. 58. Bacillus leprse, seen in a section through a subcutaneous node ; 

 x 500 (Frankel and Pfeiffer). 



the ordinary aqueous solutions of the anilin dyes color 

 it quite readily. It stains well by Grain's method, 

 by which beautiful tissue specimens can be prepared. 

 The peculiar property of retaining the color in the 

 presence of the mineral acids which characterizes the 

 tubercle bacillus also characterizes the lepra bacillus, 

 and the methods of Ehrlich, Gabbett, and Unna can be 

 used for its detection. 



Like that of the tubercle bacillus, its protoplasm often 

 presents open spaces or fractures, which have been re- 



