448 MICRO-ORGANISMS IN WATER 



BACILLUS FLAVESCENS 



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

 wasser-bacillen und iiber 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 /* long and 0-8^ broad. Slightly 

 motile. 



Cultures. 



GELATINE PLATES. Forms yellow granular 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. 



AGAK-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 Baktericn der Nutz- und Trinkiciisscr, 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. aure.ns obtained from air and described by Percy and G. C. 

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

 Trans. Roy. Sue., LSS7, p. 272. 



Microscopic Appearance. Straight or only slightly bent tine bacilli, 1-5 to 

 4 IJL long and Oo /* 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 PI.AI i.s. 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 Tn;i:s. 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. 



