418 MICRO-OKGANISMS IN WATER 



BACILLUS VEEMICULAEIS 



LIQUEFIES GELATINE 



Authority.— Percy and G. C. Franklancl, ' Ueber einige typische Mikro- 

 organismen im Wasser und im Boden,' Zeitsclirift f. Hygiene^ vol. vi., 1889, 

 p. 384. 



"Where Found. — In water from the Eiver Lea near Ohingford. An organism 

 obtained from water and subsequently described as B. vemiiculosus by Zimmer- 

 mann {loc. cit., 1890) is doubtless identical with this. 



Microscopic Appearance. — Large bacillus with rounded ends, in length 

 about 2 to 3 jti long and about 1 ^u broad. Forms extensive vermiform threads. 

 Produces oval spores about 1-5 /j. long and 1 /x broad. It is not motile. 



Cultures. — 



Gelatine Plates. — The colonies in the depth are irregular in contour. 

 This irregularity increases as the liquefaction commences, and the colony 

 approaches the surface. The periphery is seen to consist of closely -packed 

 wavy bands of bacilli, whilst the centre of the colony looks irregular and 

 wrinkled. 



Gelatine Tubes. — Forms a moist shining grey expansion, whilst in the 

 depth the path of the needle is indicated by a slight sword-like growth. Slow 

 liquefaction of the gelatine takes place. 



Agar-agak. — Produces a smooth shining greyish expansion which only 

 extends slowly. 



Potatoes.— Produces a thick irregular flesh-coloured pigment. 



Eemarks. — Powerfully reduces the nitrate to nitrite. {See p. 27-) 



BACILLUS MEGATEEIUM 



LIQUEFIES GELATINE 



Authority. — De Bary, Vergleicliende Mm-phologie imd Biologie der Pihe. 



"Where Found.— Isolated originally from cooked cabbage -leaves. Found in 

 water by Tils, ZeitschriftfUr Hygiejie, vol. ix., 1890, p. 312. 



Microscopic Appearance. — Large slightly curved bacillus with rounded 

 ends, 2'5 fi broad and 8 to 9 ^ long. Characteristic granulation of the contents of 

 the cell is visible. It has a great tendency to produce involution forms. It 

 is motile, the movements being creeping. Forms spores at the end of the 

 rod. 



Cultures. — 



Gelatine Plates. — Small round liquefying centres. 



Gelatine Tubes. — Grows principally on the surface and liquefies the 

 gelatine. 



Agae-agae. — Produces a whitish expansion, whilst the agar becomes dark 

 coloured. 



Potatoes. — Yellow white cheese-like growth, restricted to the point of 

 inoculation. 



