2. Sir William Blackstone divides duress into two sorts: First. Duress of imprisonment, where a man actually loses his liberty. If a man be illegally deprived of his liberty until he sign and seal a bond, or the like, he may allege this duress, and avoid the bond. But, if a man be legally imprisoned, and either to procure his discharge, or on any other fair account, seal a bond or a deed, this is not by duress of imprisonment, and he is not at liberty to avoid it. 2 Inst. 482; 3 Caines' R. 168; 6 Mass. R. 511; 1 Lev. 69; 1 Hen. & Munf. 350; 5 Shepl. R. 338. Where the proceedings at, law are a mere pretext, the instrument may be avoided. Aleyn, 92; 1 Bl. Com. 136.
3. Second. Duress per minas, which is either for fear of loss of life, or else for fear of mayhem, or loss of limb,; and this must be upon a sufficient reason. 1 Bl. Com. 131. In this case, a man way avoid his own act. Id. Lord Coke enumerates four instances in which a man may avoid his own act by reason of menaces: 1st. For fear of loss of life. 2d. Of member. 3d. Of mayhem. 4th. Of imprisonment. 2 Inst. 483; 2 Roll. Abr. 124 Bac. Ab. Duress; Id. Murder, A; 2 Str. R. 856 Fost. Cr. Law, 322; 2 St. R. 884 2 Ld. Raym. 1578; Sav. Dr. Rom. §114.
6. It is not every degree of violence or any hind of threats, that will invalidate a contract; they must be such as would naturally operate on a person of ordinary firmness, and inspire a just fear of great injury to person, reputation or fortune. The age, sex, state of health; temper and disposition of the party, and 0ther circumstances calculated to give greater or less effect to the violence or threats, must be taken into consideration. Id. art. 1845. The author of Fleta states the rule of the ancient common law thus: "Est autem metus praesentis vel futuri periculi causa mentis trepidatio; est praesertim viri constantis et non cujuslibet vani hominis vel meticulosi et talis debet esse metus qui in se contineat, mortis periculum, vel corporis cruciatura."
7. A contract by violence or threats, is void, although the party in whose favor the contract is made, and not exercise the violence or make the threats, and although he were ignorant of them. Id. 1846.
8. Violence or threats are cause of nullity, not only where they are exercised on the contracting party, but when the wife, the hushand, the descendants or ascendants of the party are the object of them. Id. 1847. Fleta adds on this subject: "et exceptionem habet si sibi ipsi inferatur vis et metus verumetiam si vis ut filio vel filiae, patri vel fratri, vel sorori et ahis domesticis et propinquis."
9. If the violence used be only a legal constraint, or the threats only of doing that which the party using them had a right to do, they shall not invalidate the contract A just and legal imprisonment, or threats of any measure authorized by law, and the circumstances of the case, are of this description. Id. 1850. See Norris Peake's Evid. 440, and the cases cited also, 6 Mass. Rep. 506, for the general rule at common law.
10. But the mere forms of law to cover coercive proceedings for an unjust and illegal cause, if used or threatened in order to procure the assent to a contract, will invalidate it; an arrest without cause of action, or a demand of bail in an unreasonable sum, or threat of such proceeding, by this rule invalidate a contract made under their pressure. Id. 1851.
11. All the above, articles relate to cases where there may be some other motive besides the violence or threats for making the contract. When, however, there is no other cause for making the contract, any threats, even of slight injury, will invalidate it. Id. 1853. Vide, generally, 2 Watts, 167; 1 Bailey, 84; 6 Mass. 511; 6 N. H. Rep. 508; 2 Gallis. R. 337.