486 MICRO-ORGANISMS IN WATER 



BACILLUS PUTKIFICUS COLI 



LIQUEFIES GELATINE 



Authority. — Bienstock, ' Ueber die Bakterien der Faeces,' Zeitsclwift filr 

 Mill. Med., voL viii. 



"Where Found. — In fasces. Found in water by Tils (loc. cit). 



Microscopic Appearance. — Slender bacillus, about 3 jLt long, but often 

 shorter, and often also giving rise to threads. Forms very lustrous spores, 

 round in shape, which appear usually at only one end of the rod and, remaining 

 for a time attached, recall the appearance of a drumstick. It is very motile, 

 and the bacillus may be seen moving with the spore attached. 



Cultures. — 



Gelatine Piates. — The growth has at first a shining appearance of mother- 

 of-pearl, but later it becomes yellowish. Under a low power their periphery is 

 irregular, whilst in the centre they are coarsely granulated. The periphery 

 appears to consist of wavy bands of bacillar threads. After some days the 

 centre of the colony begins to sink and the gelatine becomes liquefied (Tils). 



G-ELATiNE Tubes. — Forms a delicate expansion at the point of inoculation, 

 whilst in the depth a feeble whitish growth is visible. Later the gelatine is 

 liquefied, and a delicate pellicle forms on the surface (Tils). 



Potatoes. — ^Produces a dirty white or greyish restricted expansion. The 

 potato in the vicinity of the growth becomes dark in colour (Tils). 



BACILLUS PUNCTATUS 



LIQUEFIES GELATINE 



Authority.— 2 immerraann. Die Bakterien unserer Trinh- und Nutzw^sser, 

 insbesondere des Wassers der Chemnitzer WasserUitung ^ Chemnitz, 1890. 



"Where Found.— Frequently in the Chemnitz water supply. 



Microscopic Appearance. — Medium-sized rods, consisting of from 1 to 2, 

 rarely more, individual bacilU. The bacilli are about 0*77 ^ broad, and about 

 1-0 to 1*60 /I long. It is very motile. 



Cultures. — 



Gelatine Plates.— Forms cup-shaped liquefying colonies. In the bluish 

 grey liquid whitish dotted groups of bacteria occur, which frequently appear 

 joined to one another by white streaks. 



Gelatine Tubes.— The gelatine is liquefied in the shape of a stocking ; the 

 liquid is turbid, and a white sediment collects at the bottom. No pellicle 

 forms on the surface. 



Agar-agar.— Produces a delicate grey and shining expansion, with a 

 uniformly smooth surface. 



Potatoes.— Forms a brownish flesh-coloured expansion, which rapidly 

 covers the whole surface, and later becomes somewhat darker. 



Bemarks. — It grows better at 30^ C. than at the ordinary temperature. 



