occurring singly and in pairs with adjacent sides flattened. Gram-negative. Blood agar colonies: Small, round, smooth, convex, yellowish gray. Sometimes translucent and very adherent to the agar. Chromogenesis: The bacterial growth is usually a pale greenish yellow on Loeffler's serum medium. Acid from glucose and maltose. No acid from fructose, sucrose or mannitol. Optimum temperature, 37° C, but grows at 22° C. Easily confused with Neisseria meningi- tidis. Source: Nasopharynx. Habitat: Human mucous membrane of the respiratory tract. 9. Neisseria flava Bergey et al., 1923. (Chromogenic Group II, Elser and Hun- toon, Jour. Med. Res., 20 (N.S. 15), 1909, 415; Bergey et al.. Manual, 1st ed., 1923, 43.) fla'va. L. adj. flavus yellow. Spheres, 0.5 to 1.0 micron in diameter, occurring singly and in pairs with adjacent sides flattened. Gram-negative. Blood agar colonies: Small, circular, raised, smooth, glistening, yellowish. Chromogenesis best seen on Loeffler's serum medium; greenish yellow. Acid from glucose, fructose and maltose. No acid from sucrose. Optimum temperature, 37° C. Grows at 22° C. Source: Nasopharynx and cerebrospinal fluid in cases of meningitis (very rare). Habitat: Human mucous membrane of respiratory tract. 10. Neisseria perflava Bergey et al., 1923. (Chromogenic group I, Elser and Huntoon, Jour. Med. Res., 20 (N.S. 15), 1909, 415; Bergey et al.. Manual, 1st ed., 1923, 43.) per. fla'va. L. prefix -per very; L. adj. flavus yellow; M.L. adj. per flavus very yel- low. Spheres, 0.6 to 1.0 micron in diameter, occurring singly and in pairs with adjacent sides flattened. Gram-negative. Blood agar colonies: Small, circular, raised, yellowish, smooth, shining. Growth is often adherent to the medium. Chromogenesis best seen on Loeffler's serum medium; usually a bright greenish yellow. Acid from glucose, fructose, maltose and sucrose. Optimum temperature, 37° C. Grows at 22° C. Aerobic, facultatively anaerobic. Source: Nasopharynx, saliva and sputum. Habitat: Mucous membrane of respira- tory tract of man. The most common of the chromogenic Neisseria. Genus II. Veillonella Prevot, 193S.* (Pr^vot, Ann. Sci. Nat., Ser. Bot., 15, 1933, 118; also see Langford, Faber and Pelczar, Jour. Bact., 69, 1950, 349-356.) Veil.lo.nel'la. M.L. dim. ending -ella; M.L. fem.n. Veillonella named for A. Veillon, the French bacteriologist who isolated the type species. Small cocci, generally 0.3 to 0.4 micron in diameter, occurring in masses, in pairs or in short chains. Cells undifferentiated and united by an interstitial substance of ectoplasmic nature. Gram-negative. Good growth on usual culture media. Pronounced biochemical activity. Anaerobic. Occur as parasites in the mouths, the intestines and the urogenital and respiratory tracts of man and other animals. The present classification of the species in this genus is based on morphological and vari- ous physiological characters. However, recent work has shown that the presence of fatty acids and sulfur compounds exerts a marked influence on the morphology and/or biochem- ical behavior of these organisms; consequentlj^ in choosing criteria for the classification of the species in this genus, it seems exigent to use those obtained with specified media. With the use of rather ill-defined media, at least thirty anaerobic cocci have been recog-
- Prepared by Dr. Michael J. Pelczar, University of Maryland, College Park, Maryland,
December, 1954.
