164: BACTERIA AND THE GUM OF LINSEED MUCILAGE, 



or black tarry bodies with a low melting point. It is all a 

 question of the time that the solution remains on the water-bath 

 as to whether one obtains a yellow indefinite osazone or a brown 

 tar. In one case the gum was hydrolysed with 1 % acid, and half 

 of the neutralised solution was heated with phenylhydrazine and 

 acetic acid for three hours on the water-bath. Little more than 

 tar was formed. The second half was heated carefully for thirty 

 minutes after each addition of reagent, and a quantity of osazone- 

 like bodies was obtained. The first fraction consisted of a buff- 

 coloured powder which consisted of a mixture of osazones readily 

 soluble in ether. This solvent was used for fractionating the 

 mixture, and portions were obtained melting at 130*^, 139*^, 141 '^j 

 145'^ and 149°. The mixture probably consisted of two osazones 

 melting about 130^ and loO^"*. All the other fractions, which 

 were more or less dark in colour, were added together and treated 

 with (1) ether [twice], (2) hot water [twice], and (3) cold alcohol 

 [thrice]. When the quantity justified, the fraction was further 

 split up with ether or cold alcohol. In this way the osazone 

 product was resolved into a tarry substance and into yellow 

 osazones melting about 130"^", 150^\ 170'', and 193^. The last 

 was galactosazone. 



The above is an example of other examinations, and it is 

 evident that the gum is similar in its nature to the exuded gum 

 of Hakea saligua* The only point of difference is that in Lin- 

 seed gum there is a component that hydrolyses to galactose, 

 while in Hakea gum the nearest allied body furnished an osazone 

 melting at 190^. 



Had Linseed gum been capable of giving dextrose or arabinose 

 upon hydrolysis, the osazone of either sugar would have been 

 detected with comparative ease. These sugars are not decom- 



* Since writing the above, I have seen an abstract (Biochem. Cent. iii. 

 1904, 225) of a paper by Lemeland upon the gum of Cochlospermwn gossy- 

 pium, DC. It was hydrolysed with difficulty by 1 % sulphuric acid, pro- 

 ducing pentoses (proved by the formation of furfural), galactose and inter- 

 mediate bodies. It appears to be much the same kind of gum as that of 

 Hakea saligna and of Linseed mucilage. 



