Although the principles above stated are often overlooked, and sometimes doubted, or even denied, there are some cases in which they stand out so plainly, that everybody acknowledges for the time their truth. For example, if a man, by a blow on his head, has a piece of his skull pressed inward upon his brain, he becomes senseless, and, if he arouse at all from his stupor, his mind is obviously in an unnatural state. The surgeon raises the depressed bone, and thus taking off the pressure from the brain, restores the mind of the man to activity and sanity. In this case it is plain to every one, that the mental manifestations were suspended by a cause acting directly upon the material organization, and that they were revived again by the removal of this cause. Take another example. A man of strong and clear mind becomes deranged, and at length arrives at perfect idiocy. He goes down to the grave in this condition. No one supposes that in such a case the mind is affected independently of the body, but the mental state is of course attributed to bodily disease; and affection fondly, and we may say rationally, cherishes the expectation, that when the mind shall be freed from this tabernacle of flesh, it will emerge from its long night of darkness, and possess again its faculties in full, just as the man who lies senseless from pressure upon the brain, is restored to mental activity when that pressure is taken off by the trephine and elevator of the surgeon. Now what is true of the cases that we have cited is true in every case—all mental aberration, however slight it may be, results from the connection of the mind with the body, and would not occur without this connection. It is the product of some impression made upon the material organization, either directly, or indirectly through the mind. This impression may be momentary and evanescent, or it may produce a real change of structure. It would be interesting to enlarge upon these points, but it is not necessary for our purpose.