In most instances, however, it must be allowed, that among these old incurable cases, {142} the most powerful exciting causes are within them. When their minds are at all irradiated, striking ideas, and scenes of the past, cross their imaginations; they are further excited by them; and in proportion as the system is excited, these ideas are themselves more powerfully awakened; they have no clear consciousness nor control over themselves; and this dreaming state of their minds, to them all reality, is sometimes as cheering as the dreams of hope can make it, and at other times as horrible as the night-mare! and thus they are wrought up into the most excited or exasperated state. In some cases, especially the foregoing, this goes on until they are worn out, when they require a corresponding portion of time to renew their vital energies; and thus cause and effect mutually produce each other. These alternate states of excitement and depression, being often repeated, they gradually increase in strength and duration; and thus it is in some few cases, and especially those similar to the last, we find, that their spirits are not expended and renewed, as ours are, once in twenty-four hours, because these changes have become the habitudes of their nature, so that their system becomes governed by new laws of action. It is very singular that those most liable to extremes, are most predisposed to insanity, and in its more confirmed stage to this periodicity of excitement and depression. I have already noticed, {143} that the excitement of the depressing and exhilarating passions alternately, is the most striking characteristic of the old insane,—so striking that the general division of insanity is intomania and melancholia; a division, however, which is altogether unphilosophical, as the mania and melancholia are not any abstract difference in the cause of the disease itself, but merely the results of the over-active nervous energy operating in different directions—at one time on the depressing, another on the exhilarating passions; this indeed is the case, more or less, with all those who preserve not this mental equilibrium, but who act more from the impulse of their feelings and passions than the cold calculations of reason, and the rigid restraints of principle. To what extremes are the passions of the human mind liable, when neither the true light of the understanding nor any right sense of justice guide them! We see this in ignorant and unprincipled individuals, who suddenly rush out of their thraldom and pupilage into liberty and licensciousness; we see the same thing exhibited by agitated and wicked masses, as in the French Revolution, when the moral, like the physical ocean, is let loose from its order and control, and heaves its tumultuous waves of passion, as if by an earthquake, from one overwhelming extreme to another.