FAMILY BACILLACEAE 



715 



species named, and Zopf (Die Spaltpilze, 

 3 Aufl., 1885, 82-83) regarded the two 

 species as distinct. The modern work 

 on which the present description of Ba- 

 cillus megatherium is based has been 

 largely carried out with cultures identi- 

 fied as Bacillus megatherium, and the 

 true nature of the species is really fixed 

 by the informal emendations made in 

 these more recent descriptions. The 

 emended descriptions give this name a 

 more certain meaning than is given 

 Bacillus tumescens by the descriptions 

 existent in the literature. 



Spores: Ellipsoidal, sometimes nearly 

 round, central to paracentral, 1.0 to 1.5 

 by 1.5 to 2.0 microns (larger dimensions 

 have been reported). 



Sporangia: Ellipsoidal to cylindrical, 

 often in short chains; not swollen. 



Rods: 1.2 to 1.5 by 2.0 to 4.0 microns, 

 occurring singly and in short chains. 

 Larger and smaller cells, irregular, 

 twisted, and shadow forms are present in 

 some strains, depending upon the sub- 

 strate. Cells from glucose or glycerol 

 nutrient agar usually store much fat and 

 stain unevenly (vacuolated) with dilute 

 stains. Motility with peritrichous fla- 

 gella, usually slow, although some strains 

 may show active motility. Gram-posi- 

 tive. 



Gelatin stab: Slow liquefaction. 



Agar colonies : Large, smooth, soft, con- 

 vex, entire, opaque, creamy -white to 

 yellow. The rough stage is usually con- 

 centrically ridged with a thin edge. 



Agar slants : Growth abundant, soft, 

 butyrous, creamy-white to yellow with 

 pellucid dots. Browning with age ; a few 

 strains become black if the medium con- 

 tains tyrosine. 



Broth : Medium to heavy uniform 

 turbidity. 



Milk: Peptonized. 



Milk agar plate: Casein hydrolyzed. 



Potato : Growth abundant, smooth, soft 

 to slimy, spreading, creamy-white, pale 

 to lemon-yellow or pink. A few strains 



are orange-colored, some blacken the 

 potato. The rough stage is wrinkled. 



Nitrites usually not produced from 

 nitrates. 



Starch is hydrolyzed. 



Acid with ammoniacal nitrogen from 

 arabinose, glucose, fructose, sucrose, 

 maltose, de.xtrin, inulin, salicin, glycerol 

 and mannitol. Usually acid from xylose, 

 galactose, mannose, and raffinose; vari- 

 able from lactose. Generally no acid 

 from rhamnose. 



Acetylmethylcarbinol not formed. 



Citrates used as sole source of carbon. 



Uric acid hydrolysis : Variable. 



Optimum temperature 28°C to 35°C. 

 Maximum temperature allowing growth 

 usually between 40°C and 45°C. 



Source : Originally isolated from cooked 

 cabbage. 



Habitat: Widely distributed in soil, 

 water, and decomposing materials. 



Note : A description of Bacillus mega- 

 therium — Bacillus cereus intermediates 

 follows the description of Bacillus cereus. 



7. Bacillus cereus Frankland and 

 Frankland. (Philosoph. Transact. Roy. 

 Soc. London, 178, B, 1887, 279.) From 

 Latin cereus, waxy. 



Synonj^ms : Bacillus ellenhachensis al- 

 pha Stutzer and Hartleb, Cent. f. Bakt., 

 II Abt., 4, 1898, 31 ; Bacillus ellenhachen- 

 sis Gottheil, Cent. f. Bakt., II Abt., 7, 

 1901, 540; Bacterium petroselini Bur- 

 chard, Arb. bakt. Inst. Karlsruhe, 2, 

 1898, 39 (Bacillus petroselini Lehmann 

 and Neumann, Bakt. Diag., 4 Aufl., 2, 

 1907, 414). 



The following are given as possible 

 synonyms by Gottheil, Cent. f. Bakt., 

 II Abt., 7, 1901, 540: Bacillus ramosus 

 liquefaciens Flligge, Die Mikroorganis- 

 men, 2 Aufl., 1886, 342; Bacillus stoloni- 

 ferus Pohl, Cent. f. Bakt., 11, 1892, 142 

 (Bacterium stoloniferus Chester, Ann. 

 Rept. Del. Col. Agr. Exp. Sta., 9, 1897, 

 91 ; Achromobacter stoloniferum Bergey 

 et al., Manual, 1st ed., 1923, 136); Bacil- 

 lus limosus Russell, Ztschr. f. Hyg., 11, 



