BY R. GREIG SMITH. 397 



the Gram stain is negative. The bacteria are actively motile ; 

 the flagella vary from one, terminal, to many, peritrichous; in 

 the latter cases up to six have been observed, but there may be 

 more. 



Temperature, etc. — The optimum temperature is apparently 

 about 22° on saccharose-potato agar; the growth is most bulky at 

 22°, then at 15°, then 30°, and smallest at 37°. The organism 

 is aerobic, but grows scantily under anaerobic conditions. 



Nutrient agar plate. — At 30° the colonies are circular, white, 

 slightly raised, and moist glistening. When magnified they are 

 seen to have a smooth circular edge and contain scattered 

 granules. The deep colonies are irregular, oval or round, and 

 coarsely granular. The colour changes from white to primrose 

 yellow. 



Glucose-gelathie plate. — The colonies are white, circular but 

 sometimes lacerate, slightly raised and glistening like drops of 

 gum. The colour deepens to yellow. When magnified, granules 

 are seen scattered throughout the colony, and as growth proceeds 

 these become coarser and more numerous. The deep colonies are 

 at first dark, rough and irregular, but become rounded or moru- 

 loid. The old surface colonies are raised, slimy and streaky. 

 The medium is very slowly liquefied. 



N\Ltrient gelatine plate. —As on glucose-gelatine, but the 

 growth is not so good. 



Nutrient agar stroke. — A white, flat, moist, glistening stroke is 

 first formed; this changes to a primrose or yellow, dr}^, terraced 

 growth. The margin may be straight or lobed. 



Saccharose-potato agar stroke. — The temperature of incubation 

 has a great influence upon the appearance of the cultures. In 3 

 days at 30° the growth is yellow-buff, opaque and terraced. At 

 25° the stroke is transparent at the margin and streaked with 

 white in the centre, while the growth has flowed downwards into 

 the condensed water, which has become a thick slime. At 22° 

 the opacity and growth is more pronounced, the colour is pale 

 buff. The growth is more undulating both at 15° and at 22° 



