BACILLI 471 



BACILLUS DIFFUSUS 



LIQUEFIES GELATINE 



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

 organismen im Wasser und im Boden,' Zeitschrift filr Hygiene, vol. vi., 1881), 

 p. 396. 



Where Found.— Originally in soil, found also by TatarofE (Die Dorpater 

 Wasserbakterien^ Dorpat, 1891, p. 58) in water. 



Microscopic Appearance. — A thin slender bacillus about 1*7 /t long and 

 0*5 /* broad ; occurs singly and frequently in pairs, and occasionally gives rise 

 to long wavy threads. No spore formation observed. Lively oscillatory and 

 rotatory movements. 



Cultures.— 



Gelatine Plates. — The surface colonies are visible as thin bluish green 

 expansions which spread a long way over the gelatine. Under a low power 

 the depth colonies appear almost circular, with a somewhat serrated edge and 

 coarse granular contents. As the colony gets older the edge becomes more and 

 more irregular. In the surface colonies the centre is less sharply defined, and 

 becomes surrounded by a large very thin mottled expansion with a serrated and 

 lobular periphery. 



Gelatine Tubes. — The growth is almost entirely restricted to the surface,. 

 which becomes covered with a smooth, thin, shining greenish yellow expansion. 

 The gelatine becomes very slowly liquefied and is thereby rendered turbid. 



Agar-agar.— Forms a very thin smooth shining expansion, faint yellow or- 

 of a cream oalour. 



Potatoes.— Produces a thin faint greenish yellow smooth shining ex- 

 pansion. 



Broth. — Benders it turbid and forms a g:^eenish yellow deposit, whilst 

 flocculent particles float on the surface ; but no pellicle is formed. 



Bemarks. — Slightly reduces the nitrates to nitrites. (See p. 27.) 



BACILLUS DEVOKANS 



LIQUEFIES GELATINE 



Authority.— Zimmermann, Die Bakterien unserer Trink- und Nutzwasser^ 

 insbesondere des Wassers der Chemnitzer Wasserleitung, Chemnitz, 1890. 



"Where Found. — In a much-used well-water. 



Microscopic Appearance. — Short bacillus with rounded ends, about 0-74 /t 

 long and 0-99 to 1-5 /j. broad, occurring usually singly or in pairs, rarely in larger- 

 numbers. It is very motile. No spore formation observed. 



Cultures.— 



Gelatine Plates. — In the depth the colonies resemble small white balls ; 

 when on the surface the gelatine becomes conically depressed, and the colony 

 appears as a round irregular white, but not homogeneous, mass at the bottom. 

 Under a low power the latter looks granular and yellow grey in colour, whilst 

 all round threads varying in length extend from the periphery. 



Gelatine Tubes. — In the depth there is a growth visible on the next day along 

 the path of the needle, the upper portion of which on the second to third day is filled 

 by a more or less long bubble of air, whilst lower down white masses of material 

 make their appearance. The gelatine becomes more and more cleft, without any 

 trace of liquefaction, until finally the white growths accumulate on the bottom 

 and sides of the now enlarged path of the needle. Occasionally liquefaction 

 takes place. 



Agar-agar. — Forms a thin and evenly distributed grey expansion, which in 

 from two to three days has spread over the whole surface. 



Potatoes. — No growth 



