BY R. GREIG SMITH. 35 



Compared with other bacteria the organism is of slow growth. 

 On suitable solid media it forms raised yellowish patches, which 

 have the appearance and consistency of softened yellow bees'-wax, 

 and when treated with water the culture slowly mixes, forming 

 what appears to be a partial suspension and partial solution. 

 In stroke culture on cane-gelatine the growth collects in places 

 along the stroke, and forms characteristic hanging drops (" tear- 

 drops "). The gelatine is very slowly liquefied, the liquefaction 

 being best seen by the disappearance of the gelatine under the 

 slime, which gradually collects as the culture grows, and gravitates 

 to the bottom of the sloping gelatine. 



The Bacterial Gu3i or Slime. 

 When a pure culture of the bacterium is smeared over the 

 surface of neutral cane-gelatine or agar in a suitable vessel, and 

 incubated, a luxuriant growth is obtained after the lapse of about 

 a week. The culture is precisely similar in appearance and con- 

 sistency to cane-gum. Both have the same soft, buttery appear- 

 ance and gummy consistency, and both slowly mix with water to 

 form a pale yellow opalescent solution. The opalescence is due 

 to the suspended bacteria, from which it is rather difficult to 

 separate without at the same time removing the gum. The 

 separation cannot be effected by filtering through paper, and the 

 usual coagulating agents coagulate both gum and bacteria. 

 Aluminium hydrate, for example, forms an insoluble compound 

 with the gum. An attempt was made to clarify the suspension 

 by heating it up to three atmospheres in the autoclave, a pro- 

 ceeding which was successful with another gum-forming bacterium, 

 but the suspension was unaltered. Eventually the bacteria were 

 separated by filtration through porous porcelain. A clear solu- 

 tion of the gum was thus obtained, but at the same time it was 

 noted that a considerable amount of the gum remained on the 

 porcelain, adhering to the bacteria, even after the suspension had 

 been boiled for some time to diff'use the gum. The filtered and 

 clear solution was tested simultaneously with an opalescent 

 suspension, and it was found that the two behaved similarly on 

 the addition of the various reagents, from which we must con- 



