Adultery, the voluntary sexual intercourse of a married person with another than the husband or wife. As a topic of the law, adultery may be considered, first, as a ground of divorce; second, as a criminal offence. I. In civil cases. The adultery of either party to the marriage contract is now a ground for absolute divorce in almost all Protestant states. It was not so, however, either in Scotland or England until the reformation; and after that, though in the former country divorces a vinculo were allowed for adultery, the law remained unchanged in England for a long time, and as it had been administered in the spiritual courts ever since the Catholic period; and by the ecclesiastical law marriage was held to be an indissoluble contract, and divorces from it were prohibited. The consequence was, that though divorces a mensa et thoro, or rather separations from bed and board, were granted, the only absolute divorces to be had in England were those procured from parliament upon petition. Proceedings of this character were very expensive and cumbrous; and besides, it was the almost uniform practice of parliament to grant divorces to husbands only, and to refuse them to wives.

The divorce act of 20 and 21 Victoria, ch. 85, has partly removed this invidious distinction; but not even now have husband and wife in England equal legal rights and remedies in this respect. Under this statute the husband may have a dissolution of the marriage when the wife has since its celebration been guilty of adultery; but the wife may have such relief only when the husband since the marriage has been guilty of incestuous adultery; or of adultery with bigamy; or of rape, sodomy, or bestiality; or of adultery coupled with such cruelty as, without adultery, would have entitled the wife to a divorce from bed and board before the statute; or of adultery coupled with desertion without reasonable excuse for two years and upward. The incestuous adultery of this statute is declared to mean adultery with a woman with whom the husband could not have contracted a valid marriage, on account of her relationship to him within the prohibited degrees of affinity or consanguinity; and the bigamy of the statute means marriage of the husband with another woman during the life of his lawful wife, whether within or beyond the realm. - It has been shown that by the common law of England, at the time of the settlement of this country, adultery was ground only for a divorce a mensa; and as our law followed that of the parent state, the common law of the United States was to the same effect.

But as the power to grant such divorces was vested in England in the ecclesiastical courts, and no such tribunals were ever erected here, the jurisdiction over divorces was granted to our common law courts by special statutes. But these statutes did not limit the relief, as in England, to mere separation, but have almost universally made adultery the cause for absolute divorce; also, here as in Scotland, the law makes no distinction in favor of the husband, but administers the remedy in favor of either party to the marriage, and for the same grounds.- In reference to divorce, it is immaterial whether the paramour of the adulterous husband or wife be married or single. It is essential to the action for divorce that the adultery be voluntary. Thus a woman is not guilty of it in having intercourse with a man whom she innocently supposed to be her husband, nor if she committed the act in a state of insanity, or was forced to it by a ravisher. It has been held otherwise in Pennsylvania in regard to insanity, Chief Justice Gibson declaring that insanity so great as to efface from the mind of the wife the first lines of conjugal fidelity will be no defence to the husband's action for adultery. But this seems hardly sound, and it is probably not law in any other state.

Adultery may be committed by the contraction of a new marriage under the belief that the former husband or wife is dead, when that is not the fact; for unless the period of absence is the full term prescribed by statute for founding the presumption of death, the mere belief of it is not deemed innocent. But in such a case, if the new marriage is by law not totally void, but only voidable, the essential adultery is not committed unless the parties continue to cohabit after the passing of a decree against them; and even when a divorce regular in form has been procured, if it was invalid in fact, either because the party defendant was not within the jurisdiction or power of the court which granted it, or for any other reason, the plaintiff in the divorce suit may be guilty of adultery in contracting a new marriage. - The bill or complaint for divorce on the ground of adultery must in general allege the time and place of the commission of the act, and the name of the person with whom it was committed. The principle which requires these specifications is that the defendant is entitled to be informed with reasonable certainty of the nature of the charge made against him, so that he may have an opportunity to prepare his defence intelligently.

If, however, the name of the paramour is not known to the complainant, the allegation on this point may be to the effect that the act was done with some person unknown, and this will suffice if the bill is in other respects specific enough to make the charge definite and certain on the whole. But if the allegation of adultery is based on circumstantial evidence of its commission, as for example on the fact that the defendant is infected with a venereal disease, or that a wife is found pregnant after such an absence of the husband as precludes the presumption of access on his part, the complaint or libel will be i good if, besides charging adultery generally, it suggests such reasonable circumstances as fairly support the allegation. - The charge of adultery is made out by proof of a single act; but it is not necessary that the court or jury which decides upon the case should be furnished with demonstrative proof that the act was committed, or be absolutely convinced of the very time and place when or where it was committed. From the nature of the act, the evidence of it is and must be in the mass of cases only circumstantial.