398 BACTERIAL ORIGIN OF GUMS OF ARABIN GROUP, 



than at 30° or 37'. At 37° the growth is as at 30° but more 

 scanty. 



Glucose-gelatine stroke. — The growth is irregular, spreading, 

 sliiny, and becomes depressed in places owing to the slow 

 liquefaction of the medium. The colour changes from white to 

 canary-yellow. 



Xutrient gelatine stroke. — As on glucose-gelatine but poorer. 



Glucose-gelatine stab. — A strong filiform growth with a trans- 

 lucent, white, flat, slimy nail-head. The nail-head slowly sinks, 

 and a funicular, then stratiform, liquefied area is formed. The 

 medium may develop a few gas bubbles. Saccharose is also 

 fermented with an evolution of gas. Some races liquefy the 

 medium, slowly, and an air-bubble is produced at the top of the 

 filiform stab. Taken as a whole the liquefaction of the medium 

 is slow. 



Nutrient gelatine stab. — A smaller growth than glucose-gela- 

 tine. 



Potato. — The growth is at first dull buff, raised and irregular, 

 then becomes glistening and deep yellow. 



Bouillon. — The medium becomes turbid, and forms a loose 

 fiocculent sediment, and a thin broken surface film which adheres 

 to the sides of the glass. The sediment becomes deep yellow and 

 cohesive. The recently isolated races produced indol together 

 with nitrite in from 10 to 15 days at SO''. After the races had 

 been cultivated in the. laboratorj' for several months the red 

 nitroso-indol reaction was in some cases faint, and in other cases 

 was absent. In the bouillon ammonia could be detected, but 

 neither phenol nor sulphuretted hydrogen. 



Milk. — The medium is either unaltered or made slightly ropy 

 with a faint acid reaction. 



The bacterium has characters which mark it as being new, the 

 most important of these, being the production of arabin. I 

 accordingly name the organism Bacterium acacice (Bacillus 

 acacice b}^ Migula's s\'stem). 



