472 MICROORGANISMS IN WATER 



BACILLUS JANTHINUS (Zopf), (B. violaceus) 



LIQUEFIES GELATINE 



Authority. Zopf, Die Mikroorganismen, Fliigge, 1886, p 291. Described 

 also by Plagge and Proskauer, Zeitschrift f. Hygiene, vol. ii., 1887, p. 463, and 

 by Zimmermann (loc. cit.). The B. violaceus described by Mac6 (Ann. d'Hyg. 

 publ. ct de He'd, leg., vol. xvii., 1887), the B. violaceus described by Percy 

 Frankland (Zeitschrift f. Hygiene, vol. vi., 1889, p. 394), and the B. violaceus 

 laurentius described by Jordan (State Board of Health, Massachusetts : 

 Purification of Sewage Water, 1890, p. 838) deviate but slighjtly in the descriptions 

 given from the above. 



Where Found. In water by various investigators, but not occurring 

 frequently. Found also in hail by Bujwid (Centralblatt f. Bakteriologic, 1888, 

 vol. iii. p 1). 



Microscopic Appearance. Longer and shorter rods about 0-65 p. broad and 

 from 1-5 n to 3'5 yu long. The longer rods are often slightly bent. Rotatory and 

 vibratory movements. No spore formation observed. In the form obtained 

 originally from Berlin and described by Percy Frankland spores were observed. 

 Fraenkel (Grnndriss der Bakterienkunde, 1887, p. 184) mentions the presence 

 of spores in the B. violaceus obtained from the Berlin water. 



Cultures. 



GELATINE PLATES. In the depth they are small white dots, but on the 

 surface they form small bluish grey, almost circular discs, which towards the 

 centre are slightly raised ; after five days they appear as shining drop -like, 

 greyish yellow expansions, reaching about 2'5 mm. across. Under a low power 

 the depth colonies are nearly circular, with a sharp contour, and yellowish brown 

 in colour, which decreases in intensity towards the periphery. When they 

 become older delicate concentric rings are visible in the colony. The surface 

 colonies are pale yellow brown, which becomes so faint towards the periphery 

 that it is with difficulty distinguished from the adjacent gelatine. The edge is 

 very slightly lobular and serrated. (See Plate II. 2A, depth colony, magnified 

 100 times ; 2s, showing commencement of liquefaction, magnified 100 times ; 

 2c, later stage of liquefaction, magnified 100 times.) (Percy Frankland.) 



GELATINE TUBES. Forms a white expansion which gradually, from the 

 centre outwards, becomes of a violet blue colour. After a while the growth sinks 

 and the gelatine becomes slowly liquefied. No blue colour is visible in the 

 depth. 



AGAR-AGAR. Fairly abundant yellow or brownish white expansion, which 

 after some days, or longer, becomes of a deep violet colour. 



POTATOES. Forms a violet black expansion, which gradually covers nearly 

 the whole surface. The form described by Percy Frankland grows very badly 

 on this medium. 



