Book Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 edition. Excerpt: ...rend. 124, 1897, p. 706. a Compt. rend. 120, 1895, p. 887. 33 Compt. rend. 121, 1895, p. 502. Also 124, 1897, p. 512. Cazeneuve31 found that laccase produced only a very slight action in wines. He therefore attributed the disease to a particular enzyme and named it "Oenoxydase." He obtained it in the form of a gum by precipitating it from the wine by the addition of a large amount of alcohol. It colors guaiac blue, is active at oC. and is not entirely destroyed at 6sC. He finds that the coloring matter of wines is a phenol-like body which is oxidized by oenoxydase. Laborde32 attributes the secretion of Oenoxydase to a mould, Botrytis cinerea (sweet rot), which is present at the root of the vine. Eduard Schar13 has especially examined the enzyme in Phyto-lacca decandra. He used an extract prepared by macerating the fresh parts of the plant in glycerin containing not more than 5 or 10% of water, for a few days, then filtering. He states that an extract so prepared scarcely loses any of its activity for a year and a half. He found the extract from the leaves to be the most active, that from the root less active, and that from the flowers the least active. Schar34 states that the blue color produced by enzymes upon tincture of guaiac depends upon the formation of a peculiar oxygen combination with the resinous constituent of guaiac, the guaiaconic acid. To the blue compound he gives the name ozon-ized-guaiaconic acid. He also states that guaiaconic acid is very sensitive to the action of acids, alkalies, light, air and water and, that when the tincture is to be used as a reagent, it should be prepared fresh, of the strength of 2 to 3 per cent, of resin free from wood. The most valuable contributions regarding the action of soluble ferments...