Part 20 (1/2)

C. F. CROSS (Berl. Ber., 1895, 2609).

~CONSt.i.tUTION 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 const.i.tute the fibrous lignocelluloses.

UEBER DAS PFLANZLICHE AMYLOID.

E. WINTERSTEIN (Ztschr. Physiol. Chem., 1892, 353).

~ON VEGETABLE AMYLOID.~

(p. 224) A group of const.i.tuents of many seeds, distinguished by giving slimy or ropy 'solutions' under the action of boiling water are designated 'amyloid.' They are reserve materials, and in this, as in the physical properties of their 'solutions,' they are very similar to starch. They are, however, not affected by diastase; and generally are more resistant to hydrolysis. Typical amyloids have been isolated by the author from seeds of _Tropoeolum majus, Poeonia officinalis_, and _Impatiens Balsamina_. The raw material was carefully purified by exhaustive treatment with ether and alcohol, &c.; the amyloid then extracted by boiling with water, and isolated by precipitation with alcohol. Elementary a.n.a.lysis gave the numbers C 43.2, H 6.1. On boiling with 12 p.ct. HCl it gave 15.3 p.ct. furfural; oxidised with nitric acid it yielded 10.4 p.ct. mucic acid. Specimens from the two first-named raw materials gave almost identical numbers.

_Hydrolysis._--On boiling with dilute acids these products are gradually broken down, dissolving without residue. In this respect they are differentiated from the mucilages, which give a residue of cellulose (insoluble). From the solution the author isolated crystalline galactose, but failed to isolate a pentose. Dextrose was also not identified directly.

The tissue residues left after extracting the amyloid const.i.tuent, as above described, were subjected to acid hydrolysis. A complex of products was obtained, from which galactose was isolated. A furfural-yielding carbohydrate was also present in some quant.i.ty, but could not be isolated. The original seed tissues, therefore, contain an amyloid and a hemicellulose, the latter differentiated in its resistance to water. Both yield, however, to acid hydrolysis a complex of products of similar composition and const.i.tution.

UEBER DEN GEHALT DES TORFES AN PENTOSANEN ODER FURFUROLGEBENDEN STOFFEN UND AN ANDEREN KOHLENHYDRATEN.

H. V. FEILITZEN and B. TOLLENS (Berl. Ber., 1897, 2,571).

~CARBOHYDRATE CONSt.i.tUENTS OF PEAT.~

(p. 240) An investigation of typical peats taken at successive depths showed increasing percentage of carbon, and inversely a decreasing yield of furfural. The numbers may be compared with those for _Sphagnum cuspidatum_--with C = 49.80 p.ct., and furfural 7.99 p.ct., calculated to dry, ash-free substance:

__________________________________________________

Depth at which taken

C p.ct.

Furfural p.ct.

_______________________

_________

________________

_

20-100 cm.

51.08

6.93

I.

100-200 ”

53.52

5.30

_ 200-300 ”

58.66

3.19

_

Surface-20 ”

55.47

3.40

II.

20-60 ”

55.06

3.48

60-100 ”

58.25

1.45

100-120 ”