BY R. GREIG SMITH. 447 



some extent under the anaerobic conditions that prevailed under 

 the mica sheet in agar plate culture. 



Nutrient-agar i^late. — The colonies are dry, raised and glisten 

 faintly. They are very cohesive and are removed en masse with 

 the needle. Microscopically the centre is dark and puckered, 

 and coarse granules radiate to the margin. The modified form 

 grows as pale buff, luxuriant, raised glistening colonies. Micro- 

 scopically they are homogeneous and finely granular. 



Glucose-gelatine opiate. — The colonies develop as irregular trans- 

 lucent masses or crusts. They are friable and easily removed en 

 masse from the medium. Microscopically they appear to be 

 composed of aggregations of different-sized slime-masses arranged 

 irregularly and rising to a point in the centre. The deep colonies 

 are semi-transparent and moruloid. The colonies appear similar 

 when grown in levulose-asparagine-gelatine and in nutrient gela- 

 tine, although in the latter they are much smaller. The altered 

 form grows as a pale buff, round, slimy, circular colony. Micro- 

 scopically it is uniformly and finely granular. The deep colonies 

 are granular and opaque, with a translucent zonate margin. In 

 nutrient gelatine the colonies are white, but otherwise as upon 

 glucose-gelatine. 



Saccharose-j)otato-ayar stroke. — The growth consists of dry and 

 leathery fused crusts, which slowly develop into a luxuriant 

 elevated bunch-of-grapes structure. The derived type forms a 

 thin, scarcely visible gum, which flows into the condensed water. 

 Ultimately the growth becomes dry, whitish and glistenino-. 



Nutrient-agar stroke. — There forms a dry, pale buff growth, 

 consisting of a collection of granular, raised, dull crusts. The 

 modified bacterium grew as a pale buff, fat-glistening, raised 

 stroke, with a smooth edge. The colour deepened to a strong 

 yellow. 



Glucose-gelatine^ stroke. — A dull, translucent, raised and corru- 

 gated ribbon is developed. The altered bacterium formed a white, 

 gummy growth, which flowed downwards. By the eleventh day 

 a furrow occupied the site of the stroke; the gelatine had been 

 liquefied. 



