Nitrate reduction. B. prodigiosus, when grown in 

 nitrate solution , produces a marked reduction of nitrates into 

 nitrites. Grown in the fermentation tube, in sugarfree bouillon to 

 which 1 / KN0 3 has been added, further reduction is shown by 

 the appearance of gas bubbles at the end of the week. 



Odor. The cultures of B. prodigiosus are characterized 

 by a strong odor of trimethylamine, although , S c h e u r len states 

 that this substance is not formed. It has also been stated that 

 the odor is absent in colorless races (Schottelius). It is absent 

 in non-proteid media. 



B. prodigiosus II VIII. 



Seven so-called B. prodigiosus cultures were obtained from 

 various sources (cf. prefatory list) for comparison with B. pro- 

 digiosus I. Cultures II and III agreed with the type in all 

 respects and were probably derived from it. B. p r o d i g i o s u s IV, 



VI and VII were vigorous cultures showing characteristic lique- 

 faction of gelatin , coagulation of milk , red pigment with green 

 luster on agar and potato etc., but causing gas evolution in sucrose 

 as well as in dextrose bouillon. Agar colonies of B. prodigiosus 



VII were sometimes spreading and proteus-like. B. prodi- 

 giosus V and VIII gave a less brillant pigment of a violet red 

 color without metallic luster. No. V produced a heavy orange red 

 membrane-like pellicle in sugar free bouillon, liquefied gelatin 

 more slowly, beginning with a cup-like depression, coagulated milk 

 only in 72 hours, but showed gas bubbles in dextrose, sucrose, 

 and even in lactose fermentation tubes sooner than any other 

 Prodigiosus culture, i. e. in 48 hours. B. prodigiosus VIII 

 produced a viscid growth in ordinary media, which formed long 

 threads when touched with the needle. It coagulated milk in 

 48 hours and liquefied gelatin rapidly, but produced no gas in 

 sugar bouillon. 



B. ruber indicus (Koch, 50). 



Isolated by Koch in India from the stomach of an ape, and, 

 according to K r u s e (52), again found byPasqualein Massua. I was 

 unable to obtain the descriptions of either of these investigators, 

 but that ofFraenkel (51) must correspond closely to the original, 

 since he relates how the organism was sent to the Berlin Labo- 

 ratory by Koch, between two pieces of filter paper in a letter. 

 It was subjected to all the fumigation which the sanitary police 

 deemed necessary for documents leaving a cholera country, was 

 "durchlocht, gechlort und geschwefelt", but survived. F r a e n k e 1 

 states that it differed from B. prodigiosus in developing pig- 

 ment at 37, and in its toxicity for guinea pigs and rabbits. 



My two cultures, although evidently distinct for several years 

 (cf. prefatory list), were alike in every respect. They differed from 

 the Prodigiosus type as follows : 



Gelatin stab, the liquefied portion colored red only at the 

 surface. Agar, colonies pink in 72 hours, 3 mm in diameter, edges 



