The action of the gastric juice is chemical, and it will only dissolve dead matters, and it dissolves them when they are in tubes of metal as well as in the stomach, but it has no action upon living matter. Respiration is no more a chemical process than the absorption of chyle; and the changes that take place in the lungs, though they appear so simple, may be very complicated; it is as little philosophical to consider them as a mere combustion of carbon as to consider the formation of muscle from the arterial blood as crystallisation. There can be no doubt that all the powers and agencies of matter are employed in the purposes of organisation, but the phenomena of organisation can no more be referred to chemistry than those of chemistry to mechanics. As oxygen stands in that electrical relation to the other elements of animal matter which has been called electropositive, it may be supposed that some electrical function is exercised by oxygen in the blood; but this is a mere hypothesis. An attempt has been made founded on experiments on the decomposition of bodies by electricity to explain secretion by weak electrical powers, and to suppose the glands electrical organs, and even to imagine the action of the nerves dependent upon electricity; these, like all other notions of the same kind, appear to me very little refined. If electrical effects be the exhibition of certain powers belonging to matter, which is a fair supposition, then no change can take place without their being more or less concerned; but to imagine the presence of electricity to solve phenomena the cause of which is unknown is merely to substitute one undefined word for another. In some animals electrical organs are found, but then they furnish the artillery of the animal and means of seizing its prey and of its defence. And speculations of this kind must be ranked with those belonging to some of the more superficial followers of the Newtonian philosophy, who explained the properties of animated nature by mechanical powers, and muscular action by the expansion and contraction of elastic bladders; man, in this state of vague philosophical inquiry, was supposed a species of hydraulic machine. And when the pneumatic chemistry was invented, organic structures were soon imagined to be laboratories in which combinations and decompositions produced all the effects of living actions; then muscular contractions were supposed to depend upon explosions like those of the detonating compounds, and the formation of blood from chyle was considered as a pure chemical solution. And, now that the progress of science has opened new and extraordinary views in electricity, these views are not unnaturally applied by speculative reasoners to solve some of the mysterious and recondite phenomena of organised beings. But the analogy is too remote and incorrect; the sources of life cannot be grasped by such machinery; to look for them in the powers of electro-chemistry is seeking the living