The proteoclastic ferment is still present in zymin, which undergoes autolysis in presence of water in a similar manner to yeast-juice [Albert, 1901, 2]. As already mentioned an active juice can be prepared by grinding acetone-yeast with water, sand, and kieselguhr, and this process presents the advantage that samples of yeast-juice of approximately constant composition can be prepared at intervals from successive portions of a uniform supply of acetone-yeast. Preparations of acetone-yeast, made from yeast freed from glycogen by exposure in a thin layer to the air for three or four hours at 35° to 45°, or eight hours at the ordinary temperature [Buchner and Mitscherlich, 1904], show practically no autofermentation and may be used analytically for the estimation of fermentable sugars. All the foregoing preparations exhibit the same general properties as yeast-juice, as regards their behaviour towards the various sugars, antiseptics, etc. When zymin is mixed with sugar solution without being previously ground, it exhibits a peculiarity which is of some practical interest. The time which elapses before the normal rate of fermentation is attained and the total fermentation obtainable vary with the amount of sugar solution added, the time increasing and the total diminishing as the quantity of this increases. This phenomenon appears to have been noticed by Trommsdorff [1902], and a single experiment of Buchner shows the influence of the same conditions [Buchner, E. and H., and Hahn, 1903, p. 265, Nos. 700-1]. Harden and Young have found that when 2 grams of zymin are mixed with varying quantities of 10 per cent. sugar solution the following results are obtained:-- ───────────┬────────────────────────────────────────── Volumes of │ Total Gas Evolved in Sugar │ 1 2 3 4 22·5 hours. Solution │ ───────────┼────────────────────────────────────────── 5 c.c. │ 15·7 31·6 44·8 56·5 233·3 10 " │ 2·2 10·5 23 31·8 202·3 20 " │ 0·9 2·4 13·6 23·7 125·5 40 " │ 1·4 1·7 2·3 2·9 56·3 ───────────┴────────────────────────────────────────── [p040] This behaviour appears to be due to the removal of soluble matter essential for fermentation from the cell, which is discussed later on. It follows that when zymin is being tested for fermenting power, a uniform method should be adopted, and all comparative tests should be made with the same volumes of added sugar solution. Ground zymin appears to begin to ferment somewhat more slowly than unground (2 grm. to 12·4 c.c. of sugar solution in each case), but eventually produces the same total volume of gas [Buchner and Antoni, 1905, 1]. [p041] CHAPTER III. THE FUNCTION OF PHOSPHATES IN ALCOHOLIC FERMENTATION.