DESCRIPTIONS OF PATHOGENIC BACTERIA. 199 



lysis. The rods develop filaments which ex- 

 hibit true branching ; the branches often show 

 club-shaped buds. There are no endospores 

 as was at one time claimed, Koch having 

 mistaken vacuoles for spores. On the other 

 hand, according to Coppen-Jones chlamy do- 

 spores are actually formed. The so-called 

 tubercle bacillus is consequently not a bacillus 

 at all, but the parasitic growth-form of a pleo- 

 morphic mould. .' 



The cultures grow, although slowly, upon 

 bouillon, blood serum, and agar, and thrive best 

 when glycerine is added to these media. The 

 bacteria when derived from man and other mam- 

 mals generally grow more slowly than those ob- 

 tained from the body of fowls. Growth is first 

 apparent in the former after 14 days, in the lat- 

 ter after 8 days ; the former develop dry scales, 

 the latter a somewhat moister and smoother 

 film; the former grow between 29-42, the 

 latter between 25-44. Hueppe and Fischel, 

 by varying the conditions of cultivation, have 

 so modified the mammalian germ that it grew 

 like the germ of fowl tuberculosis, and the latter 

 like the germ of mammalian tuberculosis. 

 The virulence also was influenced in such a 

 way that mammals could be infected by the 

 bacteria of fowl tuberculosis and vice versa. 

 Consequently, the view of Maffucci and Koch 



