Thus, while for 40 equivalents of Carbon, Proteine contains only 12 of Oxygen; Lactic acid contains 40, and Tartaric 50, of that element. So it seems that Albuminous matters, containing less Oxygen, would require much more Oxygen for their combustion; this would produce more heat, augment the number of respirations, and keep up the fever. And though it has been proved by Wöhler that free vegetable acids pass out in the urine without having undergone oxidation, yet the condition of fever would probably be an exceptional case. Lactic acid, the natural fuel, being deficient, the alkali with which it should combine must be present in some excess; so it seems likely that a free vegetable acid would combine at once with this alkali as the Lactic acid would have done, and thus be burnt or oxidized instead of the latter. Its action would then be simply Restorative. Requiring less Oxygen than the Proteine would need to transform it into Carbonic acid, it would thus diminish the number of the respirations, the frequency of the pulse, the temperature of the body,--and in this way allay the fever. It would be strongly confirmatory of this idea if it were proved that the amount of Urea and Urates in the urine is actually diminished by the use of acid drinks and fruits in febrile cases. This hypothesis can only be admitted on the supposition that fever constitutes an exception to the general rule that the vegetable acids pass through the blood without undergoing change. Now, the salts of these acids, with alkalies, which are often administered in the form of effervescing draughts, might exert the same refrigerant action. But there would be this difference: the alkali of the blood would not be required, the acid being already combined with an alkali. M. Wöhler has found that these vegetable-acid salts always undergo oxidation in the system, being converted into carbonates or bicarbonates, and thus reacting on the secretions as alkalies. And so in the same way it seems that the natural lactate of soda is formed into a carbonate, the carbonic acid being afterwards freed from the base, to be excreted by the lungs. But by this natural process the quantity of alkali in the blood would not be increased, nor would it be augmented by the action of a free vegetable acid. But the change undergone by a salt of this acid would continually add to the alkaline matter already in the system. Now, alkalies have a Catalytic action on the blood, which may prove useful in some sthenic fevers; and therefore these salts have a double action, and are not simply Restorative. (_Vide Alkalies_; _Antiphlogistics_; _Antiscorbutics_.)