(131° F.), was remarkably sound, well flavoured, and still in a state of fermentation. As a matter of fact, we have proved by exact experiments that alcoholic ferments, heated in beer, can endure a temperature of 55° C. (131° F.), without losing the power of germination; but the action is rendered somewhat more difficult and slower. Diseased ferments, however, existing in the same medium, perish at this temperature, as they do in the case of wine. The beer which had not been heated, had undergone changes which rendered it quite undrinkable. Its acidity, due to volatile acids, was higher than that of the other beer in the proportion of 5 to 1. The beer which had been heated contained ½ per cent. of alcohol more than the other. [Illustration: Plate 2. Appearance under the Microscope of the Deposit from “Turned” Beer.] The deposits in the heated bottles also showed filaments of disease, but in such minute quantity that it was necessary to search many fields of the microscope to discover their existence. Those which we found after the heating must have existed in the beer before that operation; the heat had destroyed them, without sensibly altering their shape or size; they could neither multiply nor continue to exert any influence upon the components of the beer.[17] From these experiments we may easily perceive, on the one hand, that beers apparently sound to the taste do not contain these or any other filiform ferments, save in a scarcely appreciable quantity; and, on the other hand, that these same ferments appear with the first unfavourable change in the quality of the beers, and that they exist more or less abundantly in proportion to the intensity of disease. In certain extremely rare cases it may happen—so, at least, we have been assured, but we have not proved the fact ourselves—that beer may keep sound in bottle, even without the preliminary heating. This exception can only occur in the case of certain beers of a peculiar composition, which are highly hopped, and are made during the favourable months of November or December, out of the choicest materials, and fermented with yeast that happens to be pure. In the deposit of such beer, even after a lapse of several months or several years, we should find only the ordinary alcoholic ferment, the slow action of which would merely cause a gradual increase in the quantity of alcohol existing in the beer, and a diminution in the proportion of dextrine. This beer might grow old, as wine does, and remain perfectly sound.