256 CELLULOSE, LIGNIN, 'ETC. 



as a special chemical compound (gluco-lignose, gluoo-dniposc of 

 Erdmann). Erdmaim assumes that it is decomposed by hydro- 

 chloric acid with production of glucose, together with lignoae or 

 drnpose, and that with nitric acid it yields cellulose, whilst the 

 lignose or drupose undergoes further decomposition. Bente,^ 

 whe doubts the existence of glnco-drupose, shows that wood-cells 

 (? lignin) yield pyrocatechin when fused with potash. 



§ 248. Cdltdose. — The, cellulose obtained from various plants 

 in the manner indicated does not appear to be invariably of the 

 com2k)sition CgHjoOj. That isolated by Stackmann from coni- 

 ferous wood was represented by the formula 6(CgH,(,05) + H^O, 

 and the cellulose that certain sclerenchyniatous and bast-tissues 

 yielded to KoroU was of similar composition. The latter chemist 

 also prepared it from parenchymatous tissues^ and then it generally 

 possessed a composition approximately indicated by the formula 

 5(C6Hio05) 4- 2H5,0, whereas the wood of most dicotyledons 

 contains, according to Stackmann, a cellulose of the formula 

 6(05Hio05) + SHjO. In these experiments the substance was 

 exhausted with water, alcohol, dilute soda, dilute acid, a mixture 

 of one part of sulphuric acid with four of water, and chlorine- 

 water, previously to being treated with nitric add and chlorate 

 of potassium. Schuppe has shown that the action of the 

 sulphuric acid, the use of which I recommend to be discontinued, 

 results in the formation of a hydro-cellulose. If the treatment 

 with sulphuric acid was omitted, the cellulose obtained from 

 woods corresponded in composition to the formula CgHj^Oj, But 

 the cellulose isolated from apples by a process that did not in- 

 clude treatment with sulphuric acid showed a deviation in com- 

 position from the formula GgHigOg. * 



The cellulose of fungi (cf. § 249) frequently shows a com- 

 position corresponding almost exactly to the formula CgHjoOj. 



§ 249. Varieties ofCellvlose. — ^The variations observed in celluloses 

 isolated from different plaftts is partly to be ascribed to the above- 

 mentioned difference in composition, and partlyprobably to varia- 

 tions in density. For instance, the cellulose of most phanerogams 



1 Aivna!. d. Cbem. und Pharm. oxxxviii. 1, 1866, and Jahresb. f. Pharm. 

 9, 1867, Oompara aiso Bente, Ber. d. d. chem, Ges. xiii. 476, 1875 ; Joarn. 

 f. Landwirthsch. 1§6, 1876. Compare also Sevan and Cross on the cbemistry 

 of Bastfibro, Chem. Newa, xlii. 77, 91, 1880. 



* Compare the dissertationa of Keil and Treffner already quoted. 



