The only other theory I have met with, which pretends to explain the mode of this double appearance, is that of the spirit leaving the body, as we have supposed it to do in cases of dreams and catalepsy; in which instances the nerve-spirit, which seems to be the archæus or astral spirit of the ancient philosophers, has the power of projecting a visible body out of the imponderable matter of the atmosphere. According to this theory, this nerve-spirit, which seems to be an embodiment of—or rather, a body constructed out of the nervous fluid, or ether—in short, the spiritual body of St. Paul, is the bond of union between the body and the soul, or spirit; and has the plastic force of raising up an aerial form. Being the highest organic power, it can not by any other, physical or chemical, be destroyed; and when the body is cast off, it follows the soul; and as, during life, it is the means by which the soul acts upon the body, and is thus enabled to communicate with the external world, so when the spirit is disembodied, it is through this nerve-spirit that it can make itself visible, and even exercise mechanical powers. It is certain, that not only somnambules, but sick persons, are occasionally sensible of a feeling that seems to lend some countenance to this latter theory. The girl at Canton, for example, mentioned in a former chapter, as well as many somnambulic patients, declare, while their bodies are lying stiff and cold, that they see it, as if out of it; and, in some instances, they describe particulars of its appearance, which they could not see in the ordinary way. There are also numerous cases of sick persons seeing themselves double, where no tendency to delirium or spectral illusion has been observed. These are, in this country, always placed under the latter category; but I find various instances recorded by the German physiologists, where this appearance has been seen by others, and even by children, at the same that it was _felt_ by the invalid. In one of these cases, I find the sick person saying, “I can not think how I am lying. It seems to me that I am divided and lying in two places at once.” It is remarkable, that a friend of my own, during an illness in the autumn of 1845, expressed precisely the same feeling; we, however, saw nothing of this second _ego_; but it must be remembered, that the seeing of these things, as I have said in a former chapter, probably depends on a peculiar faculty or condition of the seer. The servant of Elisha was not blind, but yet he could not see what his master saw, till his eyes were opened—that is, till he was rendered capable of perceiving spiritual objects.