2. Brilliant orange-red pellicle on plain gelatin. 2. Serratia indica. B. Produce enough H2 with the CO2 from glucose to show gas in fermentation tubes. 1. Acetylmethjdcarbinol produced. 3. Serratia plymulhica. 2. Acetj'lmethylcarbinol not produced. 4. Serratia kiliensis. II. Pigment soluble in water and in alcohol. 5. Serratia piscatorum. 1. Serratia niarcescens Bizio, 1823. (Bizio, Polenta porporina, Biblioteca itali- ana o sia Giornale de lettera, scienze e arti, 30, 1823, 288; Zoagalactina imetrofa Sette, Memoria storico-naturale sull'arrossimento straordinario di alcune sostanze alimentose osservato nella provincia di Padova I'anno 1819. Venezia, 8°, 1824, 51; Monas prodigiosa Ehrenberg, Bericht ii. d. z. Bekannt-ma- chung geeigneten Verhandlungen d. Kgl. preuss. Acad. d. Wissenschaften, 1849, 354.) mar.ces'cens. L. part. adj. marcescens pining away, decaying. Description taken largely from Breed and Breed (Jour. Bact., 9, 1924, 545). Short rods, sometimes almost spherical, 0.5 by 0.5 to 1.0 micron, occurring singly and occasionally in chains of 5 or 6 elements. Motile by means of four peritrichous fla- gella. Eight to ten flagella occur on cells grown at 20° to 25° C. (de Rossi, Rivista d'Igiene, I4, 1903, 000). Gram-negative. Gelatin colonies: Thin, slightly granular, gray becoming red, circular, slightly undu- late. Medium liquefied rather quickly. Gelatin stab: Infundibuliform liquefac- tion. Sediment in liquefied medium usually red on top, white in the depth. Agar colonies: Circular, thin, granular, white becoming red. R and S colonies with mucoid variants (Reed, Jour. Bact., 34, 1937, 255). Agar slant: White, smooth, moist layer, taking on an orange-red to fuchsin color in three or four days, sometimes with a metal- lic luster. Broth: Turbid; may form a red ring at surface or slight pellicle; gray sediment. Litmus milk: Acid reaction with soft co- agulum. A red surface growth develops. Little or no digestion takes place. Potato : At first a white line appears which rapidly turns red. The growth is lu.xuriant and frequently shows a metallic luster. Indole not produced. Production of hj'drogen sulfide: Produced from cysteine, cystine or organic sulfur com- pounds containing either of these molecules. Produced from sulfur but not from sulfites, sulfates or thiosulfates (Tarr, Biochem. Jour., 27, 1933, 1869; also see ibid., 28, 1934, 192). Produces acetic, formic, succinic andlevo- lactic acids, ethanol, acetylmethylcarbinol, 2,3-butylene glycol, CO2 and a trace of H2 from glucose (Pederson and Breed, Jour. Bact., 16, 1928, 183). Grows poorly or not at all in distilled water containing urea, potassium chloride and glucose. Acetylmethylcarbinol is produced (Breed) . Nitrites produced from nitrates. Pigment soluble in alcohol, ether, chlo- roform, benzol and carbon bisulfide (Schneider, Arb. bakt. Hochsch. Karlsruhe, 1, 1894, 210). Pigment may diffuse through the agar, i.e., shows solubility in water where strains are very deeply pigmented (Breed). Pigment not produced at 35° C. Sodium formate broth (Stark and Eng- land, Jour. Bact., 29, 1935, 26) : Cultures do not produce visible gas (Breed). Odor of trimethylamine is produced. Aerobic, facultatively anaerobic. Optimum temperature, between 25° and 30° C. No growth at 37° C. Source: Isolated by Bizio and Sette from growth on corn meal mush (polenta). Habitat: Found in water, soil, milk and foods and in silk worms and other insects. 2. Serratia indica (Eisenberg, 1886) Bergey et al., 1923. (Bacillus indicus Eisen- berg, Bakt. Diag., 1 Aufl., 188Q, 1; Micrococ-
