all its surface, the epithelium, decays in places, particularly in the moister parts. The agents of disorganization, vibrios and bacteria, or rather the germs of these thread-like corpuscles, penetrate through the skin, wind into the small ducts, invade the whole blood, and by degrees all the organs. Soon they swarm everywhere, almost as numerous as the chemical molecules in the midst of which they stir and circle. The albuminoid matters are decomposed into fetid gases, escaping into the air. The fixed salts, alkaline and earthy-alkaline, slowly release themselves from the organic matters with which they combined to form the tissues. The fats oxidize, and grow acrid; the moisture dries away. Every thing volatile vanishes, and, at the end of a certain time, nothing remains save the skeleton, but a formless mingling of mineral principles, a sort of humus, ready to manure the earth. Now, all these complex operations absolutely required the intervention of the infusoria of putrefaction. In pure air, deprived of living germs, they could not have been accomplished. To check putrid fermentations, to insure the conservation of animal or vegetable substances in a state of perfect integrity, only one means avails, but that is an infallible one—that of thoroughly precluding the access to them of the aerial germs of vibrios and bacteria. Whether we adopt D'Appert's method and begin by subjecting these substances to the action of high temperature, preserving them after that in hermetically-closed vessels; or whether, as we have seen very lately practised by M. Boussingault, we introduce them into an extremely cold medium; or whether we saturate them with such salts as have antiseptic properties, in every case they are protected from putrefaction by paralyzing the effect of the lower organisms. The corruption of animals is not more possible than the fermentation of grape-juice, barley-wort, milk, etc., when it is made impossible for the germs to act. This is another fact demonstrated by M. Pasteur.
We have just used the term antiseptic, that is, capable of destroying germs, and preventing the action of ferments. The interest connected with such substances is easily understood. In truth, they are at the present time the chief objective point of therapeutic researches. At the same time that chemists and physiologists are engaged with persevering zeal in studying the functions of microscopic corpuscles in living Nature, physicians, perceiving their manifold and baneful activity in the production of disease, are seeking the means of reaching and destroying them. Every one knows those principles, like phenic acid, which are extracted from pitch, and are also found in smoke, to which they impart antiseptic properties that have been utilized from time immemorial. Other substances have been lately discovered, not less remarkable for their energetic resistance to fermentation and virus. Among the number are the alkaline sulphites and hyposulphites, which have been the object of very interesting examination on the part of an Italian physician, M. Polli; the borates and silicates of potassa and
