Notwithstanding the medical evidence may be incapable, totidem verbis, to give a clear definition of madness, so as to be suited to the conception of all persons, and to comprehend the various shapes of this disease, on account of the various notions affixed by different persons to the abstract terms he may employ; yet it is always in his power to state such perversions of thought—such projects—and such conduct, contradistinguished from that which all men hold to be rational, as shall leave no doubt on the minds of those who are to appreciate his evidence, that insanity exists: and if the person be really insane, it must be from the ignorance or neglect of the medical practitioner, if he do not satisfactorily establish his derangement, provided his opportunities of visiting and conversing with the patient have been sufficient. In those cases where insane persons have deliberately destroyed others there has been some existing and prominent delusion which has been fully believed to be TRUE and GOOD and RIGHT, which has constituted the motive, and urged on the miserable victim of this delusion to the accomplishment of his purpose. Lord Erskine in the fewest words has most impressively comprehended this subject, “_In cases of atrocity, the relation between the disease and the act should be apparent_.” And again, “_I think as a doctrine of law, the delusion and the act should be connected_.” With the lunatic the object to be attained has seldom been adequate to the hazard of the enterprize, nor has the motive been proportionate to the violence committed: in the majority of instances some previous intimation of the intended attack has been communicated, if the object has been accessible; and the warning itself has usually borne the stamp of a deranged intellect. These distempered minds have never inflicted violence for private emolument, or personal advancement, but have been persuaded, that they are selected from the mass of mankind to confer exemplary justice, and to ameliorate the condition of their species. The motive for the injury inflicted has generally been virtuous and honorable in the deluded imagination of the maniac. It is true that on most occasions there has been the utmost subtilty of contrivance and deliberate execution of the projected mischief, whether it has been directed against others, or exerted for their own destruction. The execution of the project so far from being unwise, has usually deceived and astonished the wisest; but the principle, the firm belief, the motive to action, has been the “stuff which dreams are made of.”