A convincing proof of the influence of hops on the ferment organisms is contained in the fact that beer, even after being raised to 60° C. or 70° C. (140° or 160° F.), will, if unhopped, readily take on the butyric fermentation, from which, if hopped, it would remain perfectly free. Footnote 14: For historical details, see _l’Encyclopédie_, Art. _Bière_. Footnote 15: As a wine-producing country France has been highly favoured by nature, but the consumption of beer in France is increasing every year. In 1873 the quantity of beer, paying excise duties, amounted to 7,413,190 hect., which yielded to the Treasury the sum of 20,165,136 fr. These figures are taken from a report published in 1875 by M. Jacquème, inspector of finances, who remarks that the quantity of beer upon which excise duties are paid represents, probably, not more than one-third of the total production: two-thirds of the quantity brewed evades the duties. CHAPTER II. On the Causes of the Diseases which affect Beer and Wort. From our preceding observations it will be evident that the manufacture of beer, the arrangement of breweries, and all the processes practised by the brewer immediately depend upon this fact, that beer and wort are fluids essentially liable to change. Thus it becomes a matter of extreme importance that we should have an exact knowledge of the causes and nature of the changes which affect our produce, and it may be that this knowledge will lead us to regard the conditions of the brewing industry from a novel point of view, and bring about important modifications in the practices of the trade. We might vainly search the numerous works which have been written on brewing for information respecting the proposed subject of these studies. At the most we should find the diseases to which beer is liable in the course of its manufacture, or afterwards, vaguely hinted at; perhaps we might be favoured with certain empirical recipes for disguising the evil effects of those diseases. It will be our endeavour to demonstrate the truth of the proposition we have already laid down, that every change to which wort and beer are liable is brought about solely by the development of organic ferments, whose germs are being perpetually wafted to and fro in the dust floating through the air, or distributed over the surface of the different materials and utensils used in brewing, such as malt, yeast, water, coolers, vats, tubs, casks, shovels, workmen’s clothes, and innumerable other things. It is evident that this proposition bears a marked resemblance to the one which we have demonstrated concerning the diseases of wine.[16]