BY R. GREIG SMITH. 137 



The examination, by means of plate cultures, of the tissues of 

 branches near the site of the exudate, revealed the presence of a 

 number of bacteria, many of which appeared to be capable of 

 producing gum. Some of the original colonies were slimy, ropy 

 or gelatinous and did not liquefy the gelatine, while others 

 liquefied the glucose-gelatine upon which they were growing. 

 Many of those colonies which were considered to be representa- 

 tive were picked out and grown upon saccharose-potato-agar, 

 upon ordinary nutrient agar and in saccharose-peptone- fluid. 



These secondary cultures enabled the bacteria to be classified 

 into races of several probable species. Those bacteria which 

 gave no evidence of being capable of producing slime readily 

 upon the media already mentioned as well as upon levulose- 

 asparagine-tannin-agar* were rejected as being of no importance. 

 Typical growths of the several supposed species were "plated" 

 in glucose-gelatine to ensure the purity of the bacteria. 



Two bacteria were recognised as races of Bac. levanifoviuans ; 

 one of them grew as a thin wrinkled skin on saccharose-potato- 

 agar,! while the other produced a luxuriant semi-white slime. 

 Eventually the probable formers of Hakea gum were reduced to 

 two, one of which readily produced a ropy and almost trans- 

 parent slime in saccharose-asparagine-fluid, :|: On levulose-aspara- 

 gine-tannin-agar the slime was cohesive and suggestive of a gum, 

 the solubility of which was similar to that of the natural gum. 

 The other will be referred to subsequently. 



The colonies upon glucose-gelatine were like little whitish 

 irregular masses, which appeared semi-opaque with irregularly 

 darkened patches when viewed microscopically. The stroke on 

 glucose-gelatine appeared as a broad, whitish, wrinkled ribbon 

 with a depressed centre. The gelatine was at first consumed as 

 was shown by the depression in the middle of the growth; after- 



* Levulose 20, asparagine 1, tannin 1, potassium citrate 1, agar20grni., 

 water to 1000 c.c. 



t Potato juice 250, glycerine 10, saccharose 20, agar 20 grm., ^Yater to 

 1000 c.c. 



X kSaccha Ose 50, asparagine 1, potassium citrate 5, tap-water 1000 cc. 



