240 Cellulose 



are normal constituents of all soils in which they fulfil im- 

 portant functions. They are produced in the ordinary decay 

 of buried vegetable matter. They are generally of acid pro- 

 perties, and are dissolved by alkalis to brown solutions ; they 

 have the characteristics of unsaturated compounds, being 

 readily acted upon by the halogens. They closely resemble the 

 products of decay of forest woods under ordinary conditions. 

 As chief constituents of such mixtures, Mulder recognised 

 geic acid, C 20 Hi 2 O 7 ; humic acid, C 20 H 12 O 6 ; and ulmic acid, 

 C 20 H 14 O 6 . These names and formulae, however, have little more 

 than empirical value. Products closely similar to these are ob- 

 tained on a large number of decompositions of the carbohydrates, 

 both simple (sugars &c.) and complex (starch, cellulose, &c.). 

 Those obtained by long boiling of the sugars with dilute acids 

 have been carefully investigated by Sestini (Gazzetta, 10, 121, 

 240, 355). The products are of two classes : (a) soluble in 

 alkalis, sacchulmic acid, C 4 4H 4 oO 16 ; (b) insoluble, sacchulmin, 

 0441^330! 5 ; both yielding, however, the same substitution products 

 with the halogens, of which the following may be mentioned : 

 dichloroxysacchulmide, C n H 8 Cl 2 O 6 (or C 44 H 3 2O 8 O24), and 

 sesquibromoxysacchulmide, C 22 H 18 Br 3 O n (or C 44 H 3G Br 6 O 22 ). 

 Products very similar to these have been obtained by the 

 authors from the alkaline by-products of the esparto pulping 

 process, viz. by acidification and purifying the precipitate, 

 a body of constant composition, C 42 H 48 O 8 , converted by treat- 

 ment with HC1 and KC1O 3 into the derivative C 44 H 46 C1 8 O 20 

 (J. Chem. Soc. 38, 668 ; 41, 94). The lignic acids described 

 by Lange (see p. 213), and obtained by the action of alkaline 

 solutions upon the woods, are also of similar composition. 



On further treatment (fusion) with the alkaline hydrates, these 

 products yield * aromatic ' derivatives, of which protocatechuic 

 acid is obtained in largest quantity (Lange, loc. cit. ; Demel, 

 Monatsh. 3, 769). It must be admitted, however, that the 



