acid; the same observation holds with regard to the æther of an alkaline body: But, if these two be blended together into a neutral salt, the æther must likewise be changed into a neutral; and therefore, in the formation of the medullary or staminal part of animals, the æther which before belonged to, or had the properties of some other substance, is instantaneously changed into animal æther, and remains so till the dissolution of that animal."

OUR author next observes, "That bodies require to be in a certain state or condition in order to the formation of an æther that is proper for them. for them. This condition of bodies is called an excited state: Thus, as sulphur, when fluid, does not receive the electric matter, but, when solid, instantly receives it; in the same manner, the nerves, though properly formed, do not admit an æther adapted to their nature, unless they be in an excited state. Hence," says he, "the æther of a dead, and that of a living person, are very different, although the texture and figure of the nerves be the same. The state necessary for constituting the æther of a living animal, seems to depend on heat and

moisture; because these things are absolutely necessary in the constitution of life; and hence," continues our author," the excited state of the nerves depend on heat and moisture. There are also certain circumstances," says he, " which contribute to render the state of the nerves more or less apt for accumulating æther: A spasmodic fever, for example, renders the nerves of the whole body less pervious to the motion of the æther; and hence, in cases of this nature, health, and all the vital functions, must be injured."

"THESE," our author observes," are the outlines of a new doctrine concerning the nature and functions of the nerves ;" and, upon this foundation, proceeds to give his new theory of animal heat.

"FROM the foregoing reasoning," says he, "the heat, as well as all the functions of animals, seem to be occasioned by the oscillations of the nervous æther betwixt the extremities of the sentient nerves and the brain, or, more properly, betwixt the brain and muscles. But electrical æther, as above observed, varies a little from common æther; all inelastic fluids, as was likewise formerly remarked, are non-electrics; and all solid

bodies, metals excepted, are electrics: These circumstances," says our author, seem to be owing to the oscillations of the electric matter in bodies. In the same manner," says he, "the nature of animals may be such, and the nerves may be so constituted, as to form an æther adapted to their nature, and to excite those oscillations which occasion animal heat. The wonderful effects of heat and cold upon the nerves," continues our author, "confirms this theory: Every action, and even life itself, requires a certain degree of heat; for, as the heat of the external air is so variable, it was absolutely necessary that animal bodies should be endowed with the faculty of producing a degree of heat suited to their nature, independent of external circumstances: Hence we see the reason why the degree of heat so seldom varies in the same species of animals. However, although the nervous æther is always ready for exciting heat by its oscillations; yet, in order to bring about this effect successfully, external stimuli are necessary, otherwise the æther would be in danger of stagnating, which would occasion sleep, a palsy, and, last of all, death. The most permanent of these stimuli is the pulsation of the arteries; which is the reason why heat is so connected with the circulation of the blood,

and why many authors have mistaken it for the true cause of animal heat.

OUR author now concludes with observing, "That by his theory, the varieties of heat in different parts of the body, the heat and flushing of the face from shame, and all the other phenomena of heat in animal bodies, admit of a better explanation, than by any other theory hitherto invented."

HAVING thus given a pretty full account of an attempt to explain the most abstruse operations of nature, as nearly as possible in the very words of the author, we cannot deny ourselves the liberty of making a few ob

servations.

To give a formal refutation of this authors reasoning, is no part of our plan. It is perhaps wrong to say that he has reasoned; for the whole hypothetical part of his essay is a mere farrago of vague assertions, non-entities, illogical conclusions, and extravagant fancies. His æther seems to be an exceedingly tractable sort of substance: Whenever the qualities of one body differ from those of another, a different modification of other at once solves the phenomenon. The æther of iron

must not, to be sure, be exactly the same with the nervous æther, otherwise it would be in danger of producing sensation in place of magnetism. It would likewise have been very improper to give the vegetable æther exactly the same qualities with those of animal æther; for, in such a case, men would run great risk of striking root in the soil; and trees and hedges might eradicate and run about the fields. Nothing can be more ludicrous than to see a writer treating a mere ens rationis as familiarly as if it were an object of our senses: The notion of compounding the æther of an acid and that of an alkali, in order to make a neutral of it, is completely ridiculous. But if men take the liberty of substituting names in place of facts and experiments, it is an easy matter to account for any thing.

By this method of philosophising, obscurity is for ever banished from the works of nature. It is impossible to gravel an ætherial philosopher. Ask him what questions you please, his answer is ready:As we cannot find the cause any where else; ergo, by dilemma, it must be owing to æther! For example, ask one of these sages, What is the cause of gravity? he will answer, 'Tis æther!