In the brains of epileptic idiots, who are very determined somnambulists, we discover changes the most various; _effusion_, _congestion_, _ossification of membranes_, _ramollissement_, _indurcissement_, bony _spiculæ_, or points pressing the brain, _tubercles_, _cysts_. In some, the skull assumes the density of ivory. Yet in those persons who have been known to be sleep-walkers, the inspection is seldom satisfactory. _Plethora_ of the head has often, however, preceded the sleep-walk. Signor Pozzi, physician to Benedict XIV., if he submitted not to depletion each second month, became a somnambulist; and we have known that in _chorea, previous to the dance_, and in some cases of somnambulism also, pain has been felt from the _occiput_ along the course of the _spinal marrow_. This is from immediate excitement; but _dyspepsia_ and other _abdominal derangements_ may so influence the _ganglia_ and _nerves of organic life_, and through them the brain and cord, as to excite sleep-walking by _remote_ sympathy. That injuries of the nervous matter about the nape of the neck are of the highest importance in our studies of these eccentric actions, is certain. The experiments of Flourens show that the _progressive_ or _forward_ motion of animals, is influenced by varied states of the _cerebellum_. When Majendie cut through the _corpora striata_, the animal darted forward; when the _pons Varolii_ was cut, the animal rolled over sixty times in a minute. When a soldier is struck by a ball about the _cervical vertebræ_, he often springs from the ground and drops dead. It is our duty, then, not to slight the condition of the somnambulist. If _simple irritation_ be its exciting cause, much benefit may be derived from _counter-action_ on the surface, and other remedial means. Even if there be _diseased structure_, some palliation may be afforded. As preventives of the fit, we may inculcate an abstinence from late meals, exercise in the evening previous to retirement to rest, a high pillow, &c. If the propensity continue in spite of our efforts, it will be right to have the windows fastened or locked, and the door of the chamber bolted _without_; or to confine the ankle or wrist to the bed-post by a long fillet, which may by its detention awake the sleeper on starting from the bed. IMITATIVE MONOMANIA. “Men, wives, and children, stare, cry out, and run, As it were doomsday.” JULIUS CÆSAR. There are other very curious analogies of somnambulism, which are marked by a power of action that appears preternatural. And here again we witness the irresistibility of motion, which seems to subvert the laws of gravitation and the principles of mechanics. The involuntary twitchings and contortions of _St. Vitus’s dance_ present the slighter form of these eccentric actions, which, in the intense degree, become like the fury of a raving maniac.