mena, has been considered as highly probable; and is supposed to reside in the medullary substance of the nerves. This opinion has, lately, been in a great measure corroborated by the discovery of valves of various sizes attached to the nerves, which valves are found in greater or smaller numbers, accordingly as the animal is either of a quicker or slower motion.—See Muscles.
ANIMAL ECONOMY, in its more extensive sense, implies an accurate and physiological knowledge of the use, structure, and component parts of all animal bodies; but is here intended, to signify only such a view of the human system, as may afford the means of preserving health, and promoting the useful purposes of life.
The enjoyment of "a sound mind" in a healthy body, being the greatest of earthly blessings, a portion of the time and industry of every rational being ought to be employed in the acquisition of so desirable a state. For this purpose, nothing is more essential than a proper knowledge of the various branches of animal economy, by the assistance of which we are not only enabled to preserve ourselves in perfect health, but to remove, and frequently to obviate the attack of many disorders to which we are liable, and which, from our ignorance and mismanagement, might otherwise be productive of the most fatal consequences.
Animal economy, therefore, ought certainly to form part of a liberal education. It is not, however, necessary, nor is it convenient, that all persons should be minutely instructed in the more abstract and difficult branches of medical or anatomical science; but an acquaintance with such familiar and practical parts as are of general use and application, should never be superseded by other less serviceable pursuits.
Hence we have been induced to explain and analyze, in this work, many subjects, though apparently remote from its original design, yet so intimately connected with the physical prosperity of the individual, that an omission of such articles would be irreconcilable to our chief aim—that of exploding hurtful prejudices, and communicating useful information. Of this nature and tendency, are the articles, Abdomen, Abortion, Abscesses, Air, Amputation, Aneurism, and many others in the sequel of this Encyclopædia.
ANIMAL SPIRITS are supposed to consist of a fine and subtle fluid, secreted in the cortical substance of the brain, and spinal marrow, which passes through the medullary part, and is conveyed through the cavities of the nerves to every point of the body. In support of this ingenious and probable conjecture, many arguments have been adduced: Dr. Mead, in his Essay on Poisons, contends that the existence of animal spirits is proved by the almost instantaneous diffusion of poisonous venom through the whole body; for the bite of a rattle-snake killed a dog in less than a quarter of a minute, in which time, according to Dr. Keil's computation of the velocity of the blood, the brain or heart could not have been injured by its circulation: the cause of its death must, therefore, be ascribed to a quicker medium, which can be no other than that of the animal spirits.
ANIMATION, is that property
