b. No gas in peptone broth. c. Milk unchanged. No gas in semisolid agar. 3. Peptostreptococcus putridus. cc. Milk slowly coagulated. 4. Peptostreptococcus productus. bb. Gas produced in peptone broth. Abundant gas in semisolid agar. 5. Peptostreptococcus lanceolatus . 2. No gas or fetid odor produced. a. Milk not coagulated. 6. Peptostreptococcxis micros. aa. Milk coagulated. b. Viscous sediment in broth. Semisolid agar colonies blacken with age. 7. Peptostreptococcus parvulus. bb. No viscous sediment in broth. Semisolid agar colonies do not blacken with age. 8. Peptostreptococcus intermedins. B. Strictly anaerobic on isolation, later becomes aerotolerant. 9. Peptostreptococcus evolutus. II. Cells normally occur in pairs although short chains may occur. A. Greater than 1 micron in diameter. 1. Carbohydrates not attacked. 10. Peptostreptococcus magnus. B. Not greater than 1 micron in diameter. 1. Acid from glucose and lactose. a. Encapsulated. Pathogenic. 11. Peptostreptococcus paleopneumoniae . aa. Not encapsulated. Non-pathogenic. 12. Peptostreptococcus plagarumbelli . 2. Acid from glucose but not from lactose. No growth on ordinary culture media. 13. Peptostreptococcus morhillorum. 1. Peptostreptococcus anaerobius (Kronig, 1895, emend. Natvig, 1905) Kluyver and van Niel, 1936. (Streptococcus anaerobius Kronig, Zent. f. Gyn., 19, 1895, 409; Natvig, Arch. f. Gyn., 1905, 724; Kluyver and van Niel, Zent. f. Bakt., II Abt., 94, 1936, 391, 395 and 401.) an.a.e.ro.bi'us. Gr. pref. an- not; Gr. noun aer air; Gr. noun bins life; M.L. adj. anaerobius not living in air, anaerobic. Description taken from Prevot (Ann. Sci. Nat., S6r. Bot., 15, 1933, 180). Spheres, averaging 0.8 micron in diame- ter, occurring in chains. Non-motile. Gram- positive. Gelatin: No liquefaction. Semi-solid agar (Veillon) : After 48 hours, colonies 1 to 2 mm in diameter, very regular, lenticular; gas is produced; agar slightly acidified. Martin broth: Rapid growth; no turbid- ity; sediment in 24 hours; medium slightly acidified; feeble production of gas; slight fetid odor. Martin glucose broth: Very abundant growth; gas fetid, inflammable; no hydrogen sulfide; very marked acidification. Peptone broth: Abundant, flocculent growth; gas produced at expense of pep- tone; medium not acidified; neither indole nor hydrogen sulfide is produced. Meat and liver broth: Very abundant growth; much gas produced which contains CO2 and Ho . Milk: No acid; no coagulation. Cooked protein (egg white, meat, liver, fibrin and serum) not attacked. Fresh fibrin and fresh organs partialh' disintegrated with blackening, abundant gas and a very fetid odor due in part to hydrogen sulfide. Serum broth: Abundant gas and fetid odor. Acid from glucose, fructose, galactose, sucrose and maltose. Mannitol and arabi-
