The literature on strictly anaerobic gram-negative cocci is limited, and with the exception of Veillonella gazogenes the species listed in Bergey's Manual (Breed et al., 1948) have been infrequently reported after their initial isolation. At present two genera comprise the family Neisseriaceae, Neisseria and Veillonella. The genus Neisseria is described as consisting of diplococci and the genus Veillonella of masses, rarely of diplococci. In the literature, however, authors have reported Veillonella appearing as diplococci or in small irregular clumps (Veinon and Zuber, 1898); as diplococci, tetrads, and masses (Lewkowicz, 1901); in groups as well as single and diplococcus forms (Ozaki, 1912); as spherical nonmotile cocci and diplococci (Oliver and Wherry, 1921); as "true diplococci growing in pairs like the gonococcus but very minute" (Thomson, 1923); in pairs, tetrads, small clumps, and occasionally in short chains, with pairs and clumps most common (Hall and Howitt, 1925); and as small gram-negative cocci (Branham, 1927). The status of the anaerobic cocci was reviewed by Pr6vot (1933). Recently Foubert and Douglas (1948) presented experimental data contesting the validity of the genus Veillonella. Thus the literature would seem to refute the classification as outlined in Bergey's Manual. Accordingly, an investigation was undertaken to isolate a number of anaerobic gram-negative diplococci from the mouth of normal humans, which could be studied along with reference cultures of other investigators from the standpoint of classification. MATERIALS AND METHODS Collection and plating of saliva. Samples of saliva from 51 apparently normal people were studied. These were taken at various times, from just before and after meals to midmorning and midafternoon. Sterile test tubes were given to the subjects, and they were asked to suck vigorously on their teeth and gums and collect about 2 ml of saliva. Decimal dilutions in fluid thioglycolate medium were made to 10-7 within 1 hour after collection of the sample. Duplicate plates were made with 1 ml of the 10-i and 10-7 dilutions. Approximately 5 ml of trypticase soy agar were added to each, and the plates were mixed by rotation. Production of anaerobiosis and incubation. After the plates had hardened sufficiently, they were placed in the anaerobic jars and anaerobic conditions were produced by a modification of the method suggested by Weiss and Spaulding (1937). The jar containing the plates was then incubated at 35 C for 48 hours.
