1888.] New Micro-organisms from Water and Soil. 417 



Bacillus aurantiacus. — This is a short fat bacillus of very variable 

 dimensions. No spores were observed. In drop cultivations the 

 isolated bacilli are seen to be motile. 



On gelatine plates it produces bright orange pin-heads, but on 

 potatoes it gives rise to a magnificent brilliant red-orange pigment, 

 which does not however extend far from the point of inocula- 

 tion. 



It reduces the nitrates to nitrites only very slightly in the solution 

 employed. 



Bacillus viscosus. — This is a short bacillus about three or four 

 times as long as broad, occurring mostly in pairs. No spores were 

 observed. It is exceedingly motile. 



It very rapidly liquefies the gelatine, rendering it very viscid and 

 colouring it green. On agar-agar the whole surface quickly assumes 

 a green tint. 



No reduction of the nitric acid takes place when grown in the 

 aqueous solution described. 



Bacillus violaceus. — This is a bacillus varying in thickness, some- 

 times appearing short and stout, but when grown on agar assuming 

 a far more slender appearance ; it also gives rise to short threads. 

 Spore formation was observed. In drop cultivations they are seen to 

 be motile, the movement being, however, principally vibratory and 

 rotatory. 



It produces on agar-agar a fine dark violet expansion. 



It powerfully reduces nitrates to nitrites when grown in the 

 aqueous solution employed. 



Bacillus diffusus. — A fine slender bacillus recurring frequently in 

 pairs, and giving rise also occasionally to long undulating threads. 

 No spores were observed. In drop cultivations the bacilli are seen to 

 execute vigorous oscillatory and rotatory movements, but do not 

 traverse the field of the microscope. 



On gelatine plates the colonies give rise on reaching the surface to 

 a halo, which, extending from the centre, spreads to a considerable 

 distance round, and is composed of a very thin and characteristically 

 mottled expansion. 



It slightly reduces the nitrates to nitrites when grown in the 

 aqueous solution employed. 



Bacillus candicans. — This bacillus varies very much in form in one 

 and the same cultivation and still more in cultivations with different 

 media ; sometimes it has almost the appearance of a micrococcus, at 

 other times it shows a tendency to grow into short threads. In drop 

 cultivations the same variety of forms was observed, but in no case 

 was anything but oscillatory motion visible. 



When grown on gelatine plates it produces surface expansions 

 much resembling drops of milk. 



