202 IMPORTANT VARIETIES OF FISSION-FUNGI. 



upon gelatin and agar plates no colonies develop ; (3) in 

 tubes with nitrite solution the reaction for nitrite should 

 disappear after about eight days. 



Bacterium influenzae (R. Pfeiffer). Lehm. and 

 Neum. 



Literature.— R. Pfeiffer (Z. f. H. xn, 357, 1893), with 7 plates ; 

 Delius and Kolle (Z. H. xxiv, 327) (immunity, production of 

 toxins); Grassberger (C. B. xxill, 25). 



Microscopic Appearance. — Very small, short rods, 

 about 0.4 fi broad, 1.2 /i long, often in pairs, often in 

 sputum within the cells, more rarely united in short 

 threads (68, v). Grassberger observed typical cultures 

 with a marked tendency to form thin and thicker appa- 

 rent threads, x which in part were swollen into spindle- 

 form, and at times branching could be seen. This must 

 be studied further. 



Spontaneous motion is absent. 



Staining Properties. — Somewhat poorly with the ordi- 

 nary aqueous solutions of anilin dyes, better with alka- 

 line methylene-blue, and best by the application of a very 

 dilute carbol-fuchsin solution for five minutes. With 

 faint staining, the ends are somewhat more deeply stained. 

 Not stained by Gram's method. 



Relation to Oxygen. — Obligate aerobe. 



Requirements as Regards Nutrient Media and 

 Temperature. — Grows only upon agar smeared with 

 blood (or hemoglobin) or blood-bouillon. Optimum, 

 37°. Upper limit, 43° ; lower, 26°-27°. 



Agar Streak. — (Surface smeared with blood.) Clear, 

 like glass, small, hardly confluent, almost structureless 

 colonies. 



Bouillon with Addition of Blood. — If the nutrient 

 medium is placed in a thin layer, the Bact. influenzae 

 develops as delicate, white flocculi. 



Special Nutrient Media. — According to Grassberger, 

 a mixture of agar and defibrinated blood, heated for one 



1 The pseudo-influenza bacilli described by R. Pfeiffer {I. c.) grow 

 as large thick rods and false threads, but are identical with the I. B., 

 according to Grassberger. 



