BY THOS. STEEL 



627 



Owing to the persistent opalescence of the solution, which is 

 not removed by any ordinary means of treatment such as 

 filtration with hydrate of alumina, cfec, it is not possible to deter- 

 mine the specific rotatory power of the gum except in dilute 

 solution. A solution containing 1 gram, of the crude gum in 

 100 c.c. water observed in a 100 mm. tube in a Polarimetre- 

 Laurent with monochromatic soda flame, gave a reading of 

 — 0-39° at 20° C, which is equivalent to a specific rotatory 

 power of about [a,]^' - 40° for the pure gum. 



After oxidation at 60° C. with nitric acid of 1-24 sp. gr.^ 

 oxalic acid was obtained, but neither mucic nor saccharic acids. 

 The yield of oxalic acid \'aried in different trials between 12-8 

 and 16-8 C, Ho O.j per cent, on the pure gum, the solution also 

 containing much reducing sugar. On treatment with dilute 

 hydrochloric or sulphuric acid at 60 to 70° C, the gum is readily 

 hydrolysed, the sole product being levulose, which is produced in 

 practically the theoretical quantity required by the formula : — 

 0, H,o O, h H,0 = C, H,3 O, 



In some respects this substance resembles Lippmann's levulan 

 (Ber. 14, 1509), a body found in the juice of beetroots and in the 

 residual molasses produced during the manufacture of sugar 

 therefrom. The most important points of resemblance are in 

 yielding levulose on hydrolysis, and in possessing a l?evorotatory 

 power. 



From le%ulan it differs (a) in having a much lower rotatory 

 power, that for levulan being, according to Lippmann, [ajj^ - 221°, 

 while the present substance is only about [si]^ - 40°; (6) in giving 

 no blue precipitate with Fehling's copper solution; and (c) in the 

 concentrated hot solution not gelatinising on cooling. 



In his original description of levulan [he. cit.), Lippmann stated 

 that it yielded mucic acid on oxidation with nitric acid, and this 

 statement has been copied into works of reference) Thorpe, 

 Dictionary of Applied Chemistry, ii., 280, 1891; Watts's Diction- 

 ary of Chemistr}', iii., 116, 1892; Allen's Commercial Organic 

 Analysis, i., 423, 1898). Subsequently Lippmann (Ber. 25, 3216, 



