3. Consent being essential to all valid contracts, it follows that persons who want, first, understanding; or secondly, freedom to exercise their will, cannot be parties to contracts. Thirdly, persons who in consequence of their situation are incapable to enter into some particular contract. These will be separately considered.
4. - §1. Those persons who want understanding, are idiots and lunatics; drunkards and infants,
5. - 1. The contracts of idiots and lunatics, are riot binding; as they are unable from mental infirmity, to form any accurate judgment of their actions; and consequently, cannot give a serious and sufficient consideration to any engagement. And although it was formerly a rule that the party could not stultify himself; 39 H. VI. 42; Newl. on Contr. 19 1 Fonb. Eq. 46, 7; yet this rule has been so relaxed, that the defendant may now set up this defence. 3 Camp. 128; 2 Atk. 412; 1 Fonb. Eq. n. d.; and see Highm. on Lun. 111, 112; Long on Sales, 14; 3 Day's Rep. 90 Chit. on Contr. 29, 257, 8; 2 Str. 1104.
6. - 2. A person in a state of complete intoxication has no agreeing mind; Bull. N. P. 172; 3 Campb. 33; Sugd. Vend. 154 Stark. Rep. 126; and his contracts are therefore void, particularly if he has been made intoxicated by the other party. 1 Hen. & Munf. 69; 1 South. Rep. 361; 2 Hayw. 394; see Louis. Code, art. 1781; 1 Clarke's R. 408.
7. - 3. In general the contract of an infant, however fair and conducive tohis interest it may be, is not binding on him, unless the supply of necessaries to him be the object of the agreement; Newl. Contr. 2; 1 Eq. Cas. Ab. 286; l Atk. 489; 3 Atk. 613; or unless he confirm the agreement after he shall be of full age. Bac. Abr. Infancy; I 3. But he may take advantage of contracts made with him, although the consideration were merely the infant's promise, as in an action on mutual promises to marry. Bull. N. P. 155; 2 Str. 907; 1 Marsh. (Ken.) Rep. 76; 2 M. & S. 205. See Stark. Ev. pt. iv. page 724; 1 Nott & McCord, 197; 6 Cranch, 226; Com. Dig. Infant; Bac. Abr. Infancy and Age; 9 Vin. Ab. 393, 4; Fonbl. Eq. b. 1 c. 2; §4, note b; 3 Burr. 1794; 1 Mod. 25; Stra. 937; Louis. Code, article 1778.
9. - 1. A married woman has, in general, no power or capacity to contract during the coverture. Com. Dig. Baron & Feme, W; Pleader, 2 A 1. She has in legal contemplation no separate existence, her hushand and herself being in law but one person. Litt. section 28; see Chitty on Cont. 39, 40. But a contract made with a married woman, and for her benefit, where she is the meritorious cause of action, as in the instance of an express promise to the wife, in consideration of her personal labor, as that she would cure a wound; Cro. Jac. 77; 2 Sid. 128; 2 Wils. 424; or of a bond or promissory note, payable on the face thereof to her, or to herself and hushand, may be enforced by the hushand and wife, though made during the coverture. 2 M. & S. 396, n. b.; 2 Bl. Rep. 1236; 1 H. Black. 108. A married woman has no original power or Authority by virtue of the marital tie, to bind her bushand by any of her contracts. The liability of a bushand on his wife's engagements rests on the idea that they were formed by his authority; and if his assent do not appear by express evidence or by proof of circumstances from which it may reasonably, be inferred, he is not liable. 1 Mod. 125; 3 B. & C. 631; see Chitty on Cont. 39 to 50.
11. - §3. Trustees, executors, administrators, guardians, and all other, persons who make a contract for and on behalf of others, cannot become, parties to such contract on their own. account; nor are they allowed in any case to purchase the trust estate for themselves. 1 Vern. 465; 2 Atk. 59; 10 Ves. 3; 9 Ves. 234; 12 Ves. 372, 3 Mer. Rep. 200; 6 Ves. 627; 8 Bro. P. C. 42 10 Ves. 381; 5 Ves. 707; 13 Ves. 156; 1 Pet. C. C. R. 373; 3 Binn. 54; 2 Whart. 53; 7 Watts, 387; 13 S. & R, 210; 5 Watts, 304; 2 Bro. C. C. 400; White's L. C. in Eq. *104-117; 9 Paige, 238, 241, 650, 663; 1 Sandf. R. 251, 256; 3 Sandf. R. 61; 2 John. Ch. R. 252; 4 How. S. C. 503; 2 Whart. 53, 63; l5 Pick. 24, 31. As to the transactions between attorneys and others in relation to client's property, see 2 Ves. jr. 201; 1 Madd. Ch. 114; 15 Ves. 42; 1 Ves. 379; 2 Ves. 259. The contracts of alien enemies may in, general be avoided, except when made under the license of the government, either express or implied. 1 Kent, Com. 104. See 15 John. 6; Dougl. 641. As to the persons who make contracts in equity, see Newl. Cont. c. 1, pp. l to 33.