Litmus milk: Acid, usually followed by curdling. Litmus reduced subsequent to curdling. No proteolysis. Final pH in glucose broth, between 4.2 and 4.8. Acid from glucose, maltose, sucrose and trehalose. Nearly all strains ferment lac- tose, although an occasional strain may fail to ferment or may lose its ability to ferment lactose. Salicin may or may not be fer- mented. Glycerol is fermented aerobically (Gunsalus and Sherman, Jour. Bact., Jt5, 1943, 155), but rarely anaerobically. No acid from xylose, arabinose, raffinose, inulin, mannitol or sorbitol. Starch not hydrolyzed; gelatin not lique- fied. Sodium hippurate hydrolyzed, but es- culin not split. Ammonia produced from arginine. Erythrogenic toxin not produced. Distinctive character: This species is dis- tinctive among the pyogenic group by its ability to hydrolyze sodium hippurate. Source: Isolated from milk and tissues from udders of cows infected with mastitis. Also reported to be associated with a variety of human infections, especially those of the urogenital tract. Habitat : Udder of cows infected with mas- titis. 9. Streptococcus acidoniinimus Ayers and Mudge, 1922. (Jour. Inf. Dis., 31, 1922, 40; ihid., S3, 1923, 155.) a.ci.do.mi'ni.mus. L. adj. acidus sour, acid; L. sup. adj. minimus very least; M.L. neut.n. acidum an acid; M.L. adj. acidominimus literally acid least, probably intended to mean that this organism pro- duces the least amount of acid. Description taken from Smith and Sher- man (Jour. Inf. Dis., 65, 1939, 301). Spheres. Generally occur in short chains. Serology: Does not belong to any es- tablished serological group. Action on blood: Greening (alpha hemo- lytic). No soluble hemolysin produced. Temperature relations : No growth at 10° or 45° C. Some strains are reported to pro- duce feeble growth at 45° C. Does not survive 60° C. for 30 minutes. Tolerance tests: Growth in broth con- taining 2 per cent NaCl but not 6.5 per cent NaCl. No growth at pH 9.6 or in milk con- taining 0.01 per cent methylene blue. Litmus milk: Little or no visible change. Final pH in glucose broth, between 6.5 and 5.6. Most strains fail to lower the pH below 6.0. Acid from glucose, lactose and sucrose. The majority of strains ferment maltose and trehalose. Mannitol may or may not be fer- mented. A few cultures ferment sorbitol and salicin. Arabinose, xylose, raffinose, inulin and glycerol not fermented. The fermenta- tion tests are difficult to perform with ac- curacy because of the high limiting pH. Starch and gelatin not hj^drolyzed. Sodium hippurate hydrolyzed slowly. Esculin not split by most strains. Ammonia not produced from arginine. Distinctive characters: This species may be confused with Streptococcus agalactiae because of its ability to hydrolyze sodium hippurate, but it can be differentiated easilj^ by its low acid production in glucose broth, by its inability to produce ammonia from arginine and by its inability to ferment glycerol. Source: Originally isolated from freshly drawn milk. Occurs abundantly in the bovine vagina. Also found on the skin of calves. Habitat: The bovine vagina. 10. Streptococcus salivarius Andrewes and Horder, 1906. (Lancet, 2, 1906, 712.) sa.li.va'ri.us. L. adj. salivarius salivary, slimy. Description based on studies by Sherman, Niven and Smiley (Jour. Bact., 4S, 1943, 249). Spherical or ovoid cells 0.8 to 1.0 micron in diameter. Chain length may vary from short to very long. Gram-positive. Serology: No group-specific antigen has been demonstrated. Serological types I and II have been established based upon the presence of capsular antigens (Sherman, Niven and Smiley, loc. cit.). Several ad- ditional serological types are known to exist. A cross reaction occurs between type I and Streptococcus MG (Mirick et al., Jour. Exp. Med., 80, 1944, 431). Action on blood: Indifferent (gamma re-
