FAMILY V. BRUCELLACEAE 407 



Minute, rod-shaped cells which are sometimes thread-forming and pleomorphic. Non- 

 motile. Gram-negative. Strict parasites, growing only in the presence of certain growth 

 accessor}^ substances. May or may not be pathogenic. Found in various lesions and secre- 

 tions, as well as in normal respiratory tracts, of vertebrates. 



The type species is Haemophilus influenzae (Lehmann and Neumann) Winslow et al. 



Key to the species of genus Haemophilus. 



I. Affect warm-blooded animals. 



A. Affect the respiratory tract or the conjunctiva. 



1. Dependence on V (phosphopyridine nucleotide) and X (hemin) determined. 



a. Require both V and X for growth. 



1. Haemophilus influenzae. 



2. Haemophilus aegyptius. 



3. Haemophilus suis. 



4. Haemophilus haemolyticus. 



5. Haemophilus gallinarum. 

 aa. Require either V or X for growth, but not both. 



b. Require V but not X for growth. 



6. Haemophilus parainfluenzae. 



7. Haemophilus parahaemolyticus . 

 bb. Require X but not V for growth. 



8. Haemophilus aphrophilus. 



9. Haemophilus influenzae -murium. 



10. Haemophilus ovis. 



2. Exact dependence on V and X undetermined. 



11. Haemophilus putoriorum. 



B. Affect the genital region. 



1. Require X but not V for growth. 



12. Haemophilus ducreyi. 



13. Haemophilus haemoglobinophilus. 



2. Exact dependence on V and X unknown. 



14. Haemophilus citreus. 



II. Affects cold-blooded animals. Requires diphosphothiamine but not V or X for growth. 



15. Haemophilus piscium. 



1. Haemophilus influenzae (Lehmann encapsulated. Frequently show a marked 



and Neumann, 1896) Winslow et al., 1917. tendency to bipolar staining. Non-motile. 



(Infiuenzabacillus, Pfeiffer, Deutsche med. Gram-negative. 



Wochnschr., 18, 1892, 28; also see Ztschr. Requires both the factors V and X for 



f. Hyg., 13, 1893, 357; Bacterium influenzae growth in all media. 



Lehmann and Neumann, Bakt. Diag., 1 Gelatin colonies: No growth. 



Aufl., 2, 1896, 187; Winslow, Broadhurst, Gelatin stab: No growth. 



Buchanan, Krumwiede, Rogers and Smith, ^j^^^ ^^^^ colonies: Small, circular, 



Jour. Bact., 2, 1917, 561.) 



in.flu.en'zae. Italian noun influenza 

 influenza; M.L. gen. noun influenzae of 

 influenza. 



transparent, homogeneous, entire. Satel- 

 litism with Micrococcus. 



V and X transparent agar colonies: 1 to 



Common name: The Pfeiffer Bacillus. ^ mm in diameter, bluish sheen or iridescent 



Very small rods, 0.2 to 0.3 by 0.5 to 2.0 i" transmitted light, 



microns, occurring singly and in pairs, Blood agar slant: Thin, filiform, trans- 



occasionally in short chains and at times in parent growth, 



the form of long threads. Some strains are Chocolate agar slant: Luxuriant growth. 



