Our present knowledge of such actions and effects suggests a number of new clues to genetic relationships of carbon compounds within the plant. The conclusion is certainly justified that the origin of the pentoses is referable to oxidations of the hexoses, in which this form of 'active oxygen' plays an important part.
We must note here the researches of O. Ruff, who has applied these oxidations with important results in the systematic investigation of the carbohydrates.
UEBER DIE VERWANDLUNG DER D-GLUCONSÄURE IN D-ARABINOSE (Berl. Ber., 1898, 1573).
CONVERSION OF D-GLUCONIC ACID INTO D-ARABINOSE.
D UND L ARABINOSE (Ibid. 1899, 550).
ZUR KENNTNISS DER OXYGLUCONSÄURE (Ibid. 1899, 2269).
ON OXYGLUCONIC ACID.
Ruff in these researches has realised a simple and direct transition from the hexoses to the pentoses. By oxidising gluconic acid with the peroxide the β —CHOH— group is converted into carbonyl at the same time that the terminal COOH [α] is oxidised to CO2. The yields of the resulting pentose are large. Simultaneously there is formed an oxygluconic acid, which appears to be a ketonic acid of formula —CH2OH.CO.(CHOH)3.COOH—.