448 MICRO-ORGANISMS IK WATER 



BACILLUS FLAYESCENS 



Authority. —Pohl, ' Ueber Kultur und Eigenschaften einiger Sumpf- 

 "wasser-bacillen und liber die Andwendung alkalischer Nahrgelatine,' Central- 

 blatt f. Bakteriologie, vol. xi., 1892, p. 144. 



Where Found. — In marsh-water, and isolated by means of ammonia 

 gelatine. (See p. 67.) 



Microscopic Appearance. — Bacillus 2-1 to 2-2 fj. long and 0-8^ broad. Slightly- 

 motile. 



Cultures.— 



Gelatine Plates.— Forms yellow gi'anular pin-head colonies. It grows 

 very slowly, the first colony appearing only after four days. 



Gelatine Tubes. — Expands over the whole surface of the gelatine, and 

 grows in the depth also. 



Agar-agar. —Grows on the surface, following the course of the needle, and 

 gives rise to isolated small yellow centres ; later it spreads very slowly over the 

 surface of the agar. 



Potatoes. — It grows more rapidly on this medium, a visible growth appear- 

 ing already after forty-eight hours, whilst in four days the surface is covered 

 with a slimy yellow expansion. 



BACILLUS AUEEUS 



Authority. — Adametz, Die Bakterien der Nutz- und Ti-inhiodsser^ Vienna, 

 1888. 



"Where Found. — In water, by Adametz. Eisenberg states that it is found 

 on the skin of eczema patients. It is also probable that this organism is iden- 

 tical with the B. aureus obtained from air and described by Percy and G. C. 

 Frankland, ' Studies on some new Micro-organisms obtained from Air,' Phil. 

 Trans. Hoij. Soc, 1887, p. 272. 



Microscopic Appearance. — Straight or only slightly bent fine bacilli, 1*5 to 

 4 /J. long and 0"5 /j. broad. The majority lie parallel to one another in groups ; 

 many occur in pairs or in long threads. Possesses only slight motility. No 

 spore formation observed. 



Cultures. — 



Gelatine Plates.— The colonies develop slowly and are of various shapes, 

 and even after eight days the larger number only resemble small white dots, which, 

 however, become later of a bright yellow, and finally chrome yellow, colour. 

 Under a low power they appear of various dimensions, sometimes circular and 

 sometimes elongated. They are sharply defined and of a characteristic gold 

 colour. No liquefaction of the gelatine takes place. 



Gelatine Tubes. — Grows slowly on the surface, forming an irregular and 

 raised dark chrome yellow expansion. Hardly any growth in the depth. 



Potatoes. — Produces an irregular dark chrome yellow expansion; in older 

 cultures it becomes red brown in colour. 



