XI.] 



BACILLUS : PATHOGENIC FORMS. 



155 



If bacilli grow in the depth of a fluid medium, they do 

 not form spores, as has been stated above ; and as we have 

 also seen, as new bacilli appear, or the old filaments increase 

 in length, degeneration sets in. This degeneration gradually 

 affects greater and greater numbers, and when the fluid is 



FIG. 85. FROM AN ARTIFICIAL CULTURE IN NEUTRAL PORK-BROTH OF 

 BACILLUS ANTHRACIS, WITH COPIOUS FORMATION OF SPORES. 



Magnifying power 700. (Stained with Spiller's purple.) 



exhausted for the formation of new TDacilli, it necessarily 

 follows that the whole growth gradually becomes involved in 

 the process of degeneration, the whole mass becoming 

 smaller, and finally only debris is left. Such cultures, 

 namely, those in which the degeneration involves the whole 



