452 THE RED STRING OF THE SUGAR-CANE, 



gum was forming. Upon cutting the cane across, many of the 

 vascular strings were coloured; and finally the cotton wool upon 

 which the cane rested also became crimson from the red gum 

 which had flowed down the vessels of the strings. This experi- 

 ment is, in my opinion, very significant as regards the combined 

 (symbiotic) action of the mould and the bacterium in producing 

 the red gum in the large vessels of the ^•ascular strings of the 

 sugar-cane. 



I do not contend that this is the only bacterium that will 

 assist in the red gum-formation, any more than I consider that 

 the mould is the only fungus frequenting the cane that will pro- 

 duce a red colour; but it is clear from these experiments that the 

 two are admirably adapted for producing the phenomenon. 

 Although I have found the mould associated with Bad. vascu- 

 larum in a case of red string, yet these two did not produce the 

 red colour ujDon sterile sugar-cane. Again, upon gelatine media 

 the colour produced by these two is not so pronounced as with 

 the mould and the white slime bacterium. The formation of a 

 red colour upon sterile cane by the mould and Bad. sacchari was 

 noted. A red gum traversed the vascular strings, but the colour 

 was not so brilliant nor so much distributed as with the white 

 slime bacterium. 



The bacterium differed from those which I have previously 

 obtained in forming white colonies and in producing a pasty 

 slime upon levulose-asparagine-tannin agar. Several quantities 

 of the slime w^ere prepared by growing the bacterium upon this 

 medium at different times, and from each quantity a solution of 

 a gum was obtained by digestion in the autoclave. The gum 

 mucilages prepared at different times gave identical reactions 

 with certain reagents, so that these reactions may be taken as 

 being constant and typical for the gum. The method of testing 

 the gum is to place a drop of the thick mucilage upon a sheet of 

 glass and to stir in a drop of the reagent. The following results 

 were obtained. Basic and ammoniacal lead acetates gave a white 

 clot, ferric chloride gave a brown clot, copper sulphate followed 

 by potassium hydrate gave a blue precipitate which coagulated 



