All the decompositions of organic matter, such as the decay of meats and vegetables, are now known to be forms of fermentation, due to the action of certain organisms known by the group name of bacteria. This discovery led naturally to the process of preserving organic compounds by sterilization. The principles on which this process depends are very simple. If an organic body, such as a fruit or vegetable, be subjected for some time to a high temperature,—that of boiling water will usually suffice,—the fermentation germs which it contains will be destroyed. If then it be sealed in such a way, either hermetically or with a plug of sterilized cotton, so that no living germ can reach it, decomposition cannot take place. Certain chemicals, such for instance as salicylic acid and formaldehyde, have the property of paralyzing or suspending germ action, and hence organic bodies treated with these substances may also be protected against decomposition. The activity of fermentation is made use of in the technical arts. Bread is made light by fermentation, and wine, beer, and cider are made by the fermentation of fruits and grains. Alcohol is produced by the fermentation of grains and potatoes, their starch having previously been converted into sugar by malt. Buchner has lately shown that all fermentation is of one kind, namely, that due to ferments of the diastase type. The fermentation produced by yeast, for instance, is not due, according to his observations, to the living cells, but to the products of their activity. By destroying yeast cells, by grinding and high pressure, and using their contents, he has secured a vigorous fermentation similar in every respect to that caused by the cells themselves. XI. ELECTRO-CHEMISTRY. The electric furnace, which affords a higher heat than chemists had been able to secure, has been the promoter of great advances in inorganic chemistry. Moissan (b. 1852), a French chemist, has been the most successful in applying the heat of the electric furnace to analytic and synthetic studies. One of the practical results which has come from these studies has been the virtual bridging over of the chasm which has been supposed to exist between organic and inorganic compounds. Under the influence of the heat of the electric furnace, carbon, which is the keystone of organic compounds, has been made to combine directly with the metals, forming a series of bodies known as metallic carbides. The carbide of calcium, under the action of water, yields a gas known as acetylene, which by a series of reactions can be converted into alcohol. Thus alcohol, which only a short time ago was supposed to be solely the product of organic life, is shown also to result from a simple inorganic reaction such as has been shown above.