It has been stated in a former part of this tract, that the medical evidence, in order to impress and satisfy the tribunal before which his testimony is given, should not merely pronounce the party to be insane, but ought to adduce sufficient reasons as the foundation of his opinion. For this purpose it behoves him to have investigated accurately the collateral circumstances. It should be enquired if he had experienced an attack at any former period of his life?—if insanity had prevailed in his family?—If any of those circumstances which are generally acknowledged to be causes of this disease had occurred? as injuries of the head, mercurial preparations largely or injudiciously administered—attacks of paralysis—suppression of customary evacuations, &c. It should likewise be ascertained, if previous depression of mind had prevailed, resulting from grief, anxiety or disappointment—and it should not be neglected to collect any written documents; as insane persons will very often commit to writing their feelings and opinions although they may suppress them in discourse. There appear however sufficient criteria to discriminate crime from insanity, although it must be confessed, and such has been the opinion of distinguished legal authority, that they have often seemed to be intimately blended; yet there is a partition which divides them, and it is by such well defined interposition that they are to be separated:—for madness, clear and unequivocal insanity, must be established by the medical evidence. It is not eccentricity, habitual gusts of passion, ungovernable impetuosity of temper, nor the phrensy of intoxication,[50:A] but a radical perversion of intellect, sufficient to convince the jury that the party was bereft of the reason of an ordinary man. [50:A] A broad distinction should be made between the immediate and remote effects of intoxication. A man is not held guiltless who perpetrates a crime during the state of intoxication. He voluntarily introduces into his system a stimulus which augments his ferocity, diminishes his moral affections, and overshadows his reason. But the usual effect of this stimulus is temporary, he awakes from his debauch rational, and commonly drags after him the heavy chain of reflection. It is however equally true that this single excess may be continued into permanent insanity: he may remain for many months in a state of mental derangment, and during the prevalence of his disorder may be compelled to forego all intoxicating beverage.—If such person after the elapse of several weeks from the commencement of his disorder, should, under its influence, commit a fatal outrage, no system of jurisprudence would connect the violence with the cause which originally produced the disease.