BACILLI 435 



BACILLUS EETICULAEIS 



LIQUEFIES GELATINE 



Authority.— Jordan, A Report on certain Species of Bacteria observed in 

 Sewage, State Board of Health, Massachusetts, 1890, * Purification of Sewage 

 and Water,' p. 834. 



Where Found. — In effluent from Lawrence sewage. 



Microscopic Appearance. — Long, rather slender bacillus, about 5 /j, long 

 and 1 (U broad, with slightly rounded ends ; often occur in strings of eight to ten 

 loosely connected individuals. No true spore formation observed. Exhibits a 

 slow sinuous motion. 



Cultures.— 



Gelatine Plates. — In the depth the young colonies send out long spiral 

 filaments, which give a hazy appearance to the colony. Under a low power 

 these radiating centres resemble jelly-fish with streaming tentacles. The surface 

 colonies forma considerable and irregular expansion, and the gelatine is slowly 

 liquefied. This takes place so slowly that the liquid evaporates almost as soon 

 as formed, and the colonies then resemble slight hollows or cups in the gelatine. 

 The surface of these cups presents a mottled appearance, as if it were covered 

 with fine irregular network or reticulations. 



Gelatine Tubes. — In two days the upper part of the growth has the appear- 

 ance of a cup with ' flaring ' edges. The gelatine, as in the case of the plates, is 

 liquefied very slowly, and the cup has the same reticulated structure described 

 above. In three days the filaments begin to shoot out from along the inocula- 

 tion line, but they do not often reach any very great length. 



Agar-agae. — Dull dry raised growth, and but a feeble development in the 

 depth. 



Potatoes. — Forms a white, dull and dry growth, which later assumes a, 

 characteristic woolly appearance. 



Bboth. — The liquid becomes slowly turbid, and a slight stringy precipitate 

 forms. 



Milk. - It is slowly coagulated, and gives an acid reaction. 



Bemarks. — Rapidly reduces nitrate to nitrite. (See B. cloacae, p. 433.) The 

 bacillus grows much better at 37° than at 21° to 23° C. 



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