424 M. ARMAND RUFFER. 



less darkly staining material (fig. A, a), or of dark and light 

 parts alternately (see fig. B 3, a). 



At the same time that these changes take place in the colour- 

 ing of the bacilli, the latter undergo alterations in shape and 

 size. Whereas the bacilli present in the inflammatory fluid 

 are usually straight, and very rarely bent, many of the intra- 

 cellular bacilli are curved on themselves (see figs. A and B). 

 This is better seen in sections made at the point of injection 

 in animals inoculated with a weak virus, in which, as we have 

 seen, the bacilli have a tendency to join together end to end. 

 These intra-cellular rods are nearly always curved, and present 

 a highly characteristic appearance (figs. A, B). 



The intra-cellular bacilli in later stages of degeneration show 

 a diminution in thickness. Many are much thinner than 

 normal (fig. B 3, «, b) ; and while the diminution of thickness 

 in some bacilli is uniform, in others it begins at one extremity, 

 the bacillus looking as if one end of it were being eaten away 

 (fig. B 3, c). The contours of the intra-cellular micro- 

 organisms, also, instead of being sharply defined as in the 

 extra-cellular bacilli, are irregular, and their exact outline 

 is by no means easily traced out (see figs. A and B 3, a). 

 In a later stage the bacilli become thinner and thinner, 

 more and more irregular (fig. B 2, «, b), and lose whatever 

 power they still possessed of retaining colouring matter, so 

 that finally nothing is left in the cells but small dots (figs. 

 A, c, d, e, and B 1, a), some of which still retain more or 

 less colouring matter, whilst others appear as light, highly 

 refracting granules, or very pale rods, looking like the remnants 

 of the sheaths of dead bacilli. 



Occasionally intra-cellular bacilli are met with which, instead 

 of taking up aniline dyes, stain with carmine or logwood. 

 Others stain partly with carmine and partly with aniline dyes, 

 looking like little dots stained purple and red alternately. 



When a small dose of a weak virus is inoculated subcu- 

 taneously, the struggle between leucocytes and bacilli is 

 evident on the fifth day, or even later; but the number of 

 micro-organisms gradually diminishes, so that after the fourth 



