BACILLI 431 



BACILLUS HYALINUS 



I LIQUEFIES GELAT INE | 



Authority.-- Jordan, A Bej^ort on certam Species of Bacteria observed in 

 Sewage, State Board of Health, Massachusetts, 1890, ' Purification of Water 

 and Sewage,' p. 835. 



"Where Found.— Isolated from the sand of ti tank used for filtering sewage 

 at Lawrence. 



Microscopic Appearance.— Large, long, stout bacilli, with rounded ends. 

 Usually occurring in short strings. No spore formation observed. About 3-6 

 to 4 ^ long and 1*5 ^u broad. Very motile. 



Cultures. — 



Gelatine Plates. — Grows rapidly and is visible in twenty-four hours. The 

 centre is dark, surrounded by a broad, translucent zone, whieh gives a hazy 

 appearance to the colonies. Under a low power the contents are coarsely 

 fibrillar, with short fibrils radiating from the edge. The colonies in two days 

 are about 1 and 1^ c.c. in diameter, the contour is evenly round, the interior 

 shghtly translucent ; the rim is distinct, opaciue, yellowish, whilst towards the 

 edge the radiating fibrils are still visible. 



Gelatine Tubes. — Forms in two days a long, narrow, funnel-shaped growth. 

 The gelatine, which is rapidly liquefied, is at first cloudy, and a precipitate 

 forms at the bottom of the funnel. In about eight days a lustrous, tenacious, 

 white scum forms on the surface ; the gelatine, which is completely fluid, is 

 perfectly transparent, and at the bottom of the tube there rests a slight floccu- 

 lent deposit. 



Agar-agae. — Forms rapidly a spreading, dry, dull greyish growth. It is 

 tough and rather thin. After about four or five days small warty projections 

 appear. It grows well in the depth. 



Potatoes. — Forms a spreading, dry, whitish grey growth, but less rapidly 

 than on agar. Later small protuberances appear on the surface. 



Broth. — Renders it turbid, with a thick pellicle and a stringy precipitate. 



Milk. — In seven days strongly coagulated. Acid reaction. 



Remarks. — It grows better at 37° than at 21° or 23° C. Reduces nitrates vigor- 

 ously and rapidly. (See under B. cloacae, p. 433.) 



