254 



CELLULOSE, LIGNIN, ETC. 



an ultimate analysis of the material that had been thus treated, 

 both before and after the action of chlorine-water. Several varieties 

 of wood yielded tolerably concordant results. The lignin of 

 dicotyledons appeared to contain between 53*1 and 59 '6 per cent. 

 of carbon, 4-4 and 6 '3 per cent, of hydrogen, 34-1 and 38-9 per 

 cent, of oxygen ; the majority of his results agree very well with 

 Fr. Schulze's 1 (0 = 55-5, H = 5'8, = 38-6); but German walnut 

 and mahogany show a little variation, probably due to the larger 

 amount of foreign substances they contain. All the dicotyledonous 

 woods examined by Schulze and Stackmann must have contained 

 at least one substance in notable quantity, viz. wood-gum, which 

 was not discovered until after the publication of Stackmann's 

 work. Experiments made by Schuppe, 2 at my suggestion, showed 

 that poplar wood contained 3*25 per cent, of wood-gum, mahogany 

 3'37, American walnut 4'56, German walnut, 6'32, oak 6'03, and 

 alder 7 '09. Deducting the wood-gum present, the average amount 

 of lignin in the majority of woods is about 17 per cent, 

 (mahogany 20 '4), and its mean composition, 60 '5 6 per cent. 0, 

 4 '66 per cent. H, and 34 '80 per cent. 0. In this respect it ap- 

 proaches catechin, many tannins and phlobaphenes, and agrees 

 fairly well with the lignin of coniferous woods which contain no 

 wood-gum. Stackmann found about the same quantity of lignin 

 in the wood of gymnosperms as Schuppe did in that of angio- 

 sperms, viz. 16 to 17 per cent. 



Koroll 3 found the lignin of sclerenchymatous tissue (hazel-nut, 

 walnut) to contain from 51 -5 to 54 -2 per cent, of carbon, 4'8 to 

 5-5 per cent, of hydrogen, and 401 to 44 -7 of oxygen, and esti- 

 mated its quantity at 14 '3 to 15 '7 per cent. A substance re- 

 sembling wood-gum also occurs in the sclerenchymatous tissue of 

 nut-shells. Bast-fibres (lime and elm) yielded him 14'5 to 15*8 

 per cent, of lignin, containing 53 '6 to 54'9 per cent, of carbon, 

 4'9 to 6'0 per cent, of hydrogen, and 40'1 to 40'4 per cent, of 

 oxygen. 



On the other hand, from the outer birch-bark (rich in cuticular 

 substance,) chlorine-water extracted 11 per cent, of a substance 

 of an entirely different composition; viz. = 727, H = 7'S, 

 = 19-4. (Cf. 250.) 



1 'Beitr. z. Kenntniss d. Lignins.' Rostock, 1856. 



2 Beitrage z. Chemie d. Holzgewebes. Diss. Dorpat, 1882. 



3 ' Quant, chem. Unters. iiber d. Zusammensetz. d, Kork-, Bast-, Scleren- 

 chym. und Markgewebes.' Diss. Dorpat, 1880. 



