Xxiii . the Ether - Soluble Substances of Cabbage Leaf Cytoplasm

IN a series of papers [Chibnall and Channon, 1927, 1, 2, 3; Channon and Chibnall, 1927], we have recorded certain results which we have obtained in the analysis of the ether extract of the leaf-cell cytoplasm of the cabbage. The object of the present paper is to discuss these results so far as is at present possible from their chemical and physiological aspects, and, in passing, to refer to our investigations of the pigments and of the unsaturated portion of the unsaponifiable fraction of which no account has yet been given. For simplicity in presentation, we propose to confine all further remarks on this investigation to batch R, consisting of 220 g. of ether extract prepared from 220 kg. of cabbage leaves. By methods already described, this extract was separated into the following fractions. A. The fraction precipitated by acetone, which was further subdivided into I. The fraction insoluble in hot acetone, wt. 57x8 g. II. The fraction soluble in hot acetone, ,, 35 0 g. B. The fraction soluble in acetone-ether, ,, 119x9 g. Saponification of an aliquot part showed that this fraction contained III. Fatty acids soluble in light petroleum, wt. 38-3 g. IV. Unsaponifiable matter ,, 48-6 g. V. Acidic products insoluble in light petroleum, consisting of chlorophyll derivatives and possibly hydroxy-acids. As a preliminary to the further study of fractions (IV) and (V) it was necessary to determine the chlorophyll content of the original ether extract.