204 IMPORTANT VARIETIES OF FISSION-FUNGI. 



blood. If the first remain sterile, while delicate, drop- 

 like colonies develop upon the second, it speaks in favor 

 of influenza. Bouillon and agar mixed with sterile pigeon 

 blood are highly recommended. 



Related Varieties. — The "bacillus of pneumonia in rabbits," culti- 

 vated by Beck, E. Pfeiffer's assistant, from rabbits dying sponta- 

 neously, is closely related (Beck, Z. H. xv, 363, 1893). Small, 

 fine, non-motile bacilli, twice as long and thick as the influenza 

 bacillus, obligate aerobe, not stained by Gram's method. Does not 

 grow on potato. Upon gelatin it resembles the streptococcus. Upon 

 agar, grayish-yellow, with granular, sharp border, of tough, mucoid 

 consistenc}'. Guinea-pigs, rabbits, and mice are susceptible. Prin- 

 cipal changes upon section are pulmonary hyperemia and atelectasis, 

 and fibrinous deposit upon the pleura. 



Bacterium aegyptiacum (L. and N.). 



Ordinary Name. — Koch-Weeks' bacillus. 



Entire literature by Kamen (C. B. xxv, 449), with beautiful 

 photographs. 



Microscopically, very small, thin rods (1-2 ix long); in 

 recent cases are often exceedingly numerous in the secretion 



Fig. 16. — Bact. segyptiacum Fig. 17. — Bact. duplex (L. 



(L. andN.). andN.). 



from the eye ; sometimes they form short chains. Non- 

 motile, do not stain by Gram's method. The cultures 

 resemble in every way those of the influenza bacillus ; 

 their growth is always poor, best upon nutrient media 

 smeared with blood. Optimum at 37°. They live only 

 a short time — about four days. Scarcely at all pathogenic 



