If either of the parties professing to contract marriage be at the time defective in the points enumerated in the preceding section, it is a good ground of divorce; but to establish such defect, and especially the defect of corporeal ability, the strongest evidence must be adduced,^[256] not merely on the general maxim that the best possible evidence which the case will allow must always be produced, but also as the particular fact to be proved is or may be contrary to the general order of nature, and therefore requires more than ordinary proof for its establishment: to such points therefore the medical practitioner is required to give his most sedulous attention, first to the question in the abstract, contrasting his own experience with the opinions and traditions which he may find upon the subject, and divesting his mind of all speculative and theoretical doctrines which he does not find supported by well authenticated facts; thus prepared his second object will be an attentive, accurate, and scientific examination of the immediate case in question. The defect may be mental^[257] or corporeal; thus it may proceed from antipathy to a particular woman, when it has been called impotentiam or maleficium erga hanc; this was the alleged case of the Earl of Essex, in the time of James the 1st; for which see 1 Harg. St. Tri. 315: 2 How. St. Tri. 786.; and for the very curious argument and narative of Abbot, Archbishop of Canterbury, see 10 Harg. St. Tri. Appendix, p. 4. How far this case may be depended on, except as a beacon to show us what we ought to avoid, may be exceedingly doubtful. The character of the Lady Essex, afterward infamous as Countess of Somerset for the murder of Sir Thomas Overbury, may lead us to suspect every species of imposition and falsehood. The Judges, according to the testimony of their coadjutor the Archbishop, had predetermined to decide in favor of the divorce; no sufficient evidence appears to have been required or received, and the king, making himself at once the advocate and partisan of his unworthy favourite, urged the business with an indecent and arbitrary heat. From the worst of the Stuarts, and the pedantic believer in witchcraft (for maleficium^[258] was then used in this sense) such conduct was not extraordinary; in the present day we may boast with confidence that similar interference would be impossible. With these defects, the case of the Earl of Essex can be of little or no use to the medical jurist; and unfortunately we have no other which is reported with sufficient accuracy or authenticity; we say unfortunately, because though there may be much of good policy and correct feeling in the determination of our Civilians to conceal the detail of such cases from the public eye,^[259] yet by drawing their line too strictly, they run no inconsiderable risk of totally excluding those lights of science, of which in so dark and intricate a subject they must necessarily stand in need. It is true that the ecclesiastical courts may have the benefit of medical evidence in every case which is brought before them, but this evidence will be necessarily imperfect, unless founded on previous study, and some knowledge of the points, to which the practice of the Court will require the witness to direct his attention. In France, where causes of this kind may perhaps have been more frequent, and where less reserve is used than suits our national character, several cases have been published, for which see the Collection des Causes celebres, and Bayle’s Dictionary, tit. Quellenec & Parthenai, with the references there given.

We have stated that the defect of corporeal ability^[260] may proceed from mental or bodily causes; of the former the instances must be exceedingly rare, and the latter are certainly not numerous: but the reader will find the information which he may require upon this subject in the following physiological illustrations.