[10] See more particularly: Lindsey and Tollens, _Annalen_, 267, 341; Cross and Bevan's _Cellulose_, pp. 197-203; Street, Inaug.-Diss., Goettingen, 1892; Klason, _Rep. d. Chem. Ztg._ 1897, 261; Seidel and Hanak, _Mitt. d. Techn. Gew. Mus._ 1897-1898. SECTION VII. PECTIC GROUP UNTERSUCHUNGEN UeBER PECTINSTOFFE. R. W. TROMP DE HAAS and B. TOLLENS (Lieb. Ann., 286, 278). UeBER DIE CONSTITUTION DER PECTINSTOFFE, B. TOLLENS (ibid. 292). ~INVESTIGATIONS OF PECTINS.~ (p. 216) It is generally held that the pectins are, or contain, oxidised derivatives of the carbohydrates. The authors have isolated and analysed a series of these products, and the results fail to confirm a high ratio O : H. The following are the analytical numbers: ________________________________________________ | | | | | | | Pectin from | Ash | C | H | Ratio H : O | |______________|______|______|_____|_____________| | | | | | | | Apple | 6.2 | 43.4 | 6.4 | 1 : 7.9 | | Cherry | 20.5 | 42.5 | 6.5 | 1 : 7.9 | | Rhubarb | 4.2 | 43.3 | 6.8 | 1 : 7.4 | | Currant | 5.0 | 47.1 | 5.9 | 1 : 8.5 | | Greengage | 3.3 | 43.0 | 5.9 | 1 : 8.5 | | Turnip | 7.3 | 41.0 | 5.9 | 1 : 9.0 | |______________|______|______|_____|_____________| Acid hydrolysis (4 p.ct. H_{2}SO_{4}) gave syrupy products not crystallisable--in certain cases the hydrolysis was accompanied by separation of insoluble cellulose. The insoluble product from currant pectin had the composition C 54.4, H 5.0. Tollens points out that the results of empirical analysis are inconclusive; and that from the acid reactions of these products and their combination with bases, carboxylic groups are present, though probably in anhydride or ester form. The pectins may be regarded as closely related to the mucilages (_Pflanzenschleim_), differing from them only by the presence of the oxidised groups in question. UEBER DIE CONSTITUTION DER PECTINSTOFFE. C. F. CROSS (Berl. Ber., 1895, 2609). ~CONSTITUTION OF PECTINS.~ It is pointed out that the composition of the pectin of white currants, as given in the preceding paper, is that of the typical lignocellulose, the jute fibre. The product was isolated and further investigated by the author. It gave 9.8 p.ct. furfural on boiling with HCl (1.06 s.g.), reacted freely with chlorine, giving quinone chlorides, and with ferric ferricyanide to form Prussian blue. This 'pectin' is therefore a form of soluble lignocellulose. The 'pectic' group consequently must be extended to include hydrated and soluble forms of the mixed complex of condensed and unsaturated groups with normal carbohydrates, such as constitute the fibrous lignocelluloses. UEBER DAS PFLANZLICHE AMYLOID. E. WINTERSTEIN (Ztschr. Physiol. Chem., 1892, 353). ~ON VEGETABLE AMYLOID.~