3. But to this rule there are several exceptions. 1. There is a class of persons who are incapable of purchasing except sub modo; and, 2. Another class, who, in consequence of their peculiar relation with regard to the owners of the thing sold, are totally incapable of becoming purchasers, while that relation exists.
4. - 1. To the first class belong, 1st. Infants under the age of twenty-one years, who may purchase, and at their full age bind themselves by agreeing to the bargain, or waive the purchase without alleging any cause for so doing. If they do not agree to the purchase after their full age, their heirs may waive it in the same manner as they themselves could have done. Cro. Jac. 320; Rolle's Ab. 731 K; Co. Litt. 2 b; 6 Mass. R. 80; 6 John. R. 257.
5. - 2d. Femes covert, who are capable of purchasing but their hushands may disagree to the contract, and divest the whole estate; the hushand may further recover back the purchase-money. 1 Ld. Raym. 224; 1 Madd. Ch. R. 258; 6 Binn. R. 429. When the hushand neither, agrees nor disagrees, the purchase will be valid. After the hushand's death, the wife may waive the purchase without assigning any cause for it, although the hushand may have agreed to it; and if, after her hushand's death, she do not agree to it, her heirs may waive it. Co. Lift. 3 a; Dougl. R. 452.
6. - 3d. Lunatics, or idiots, who are capable of purchasing. It seems that although they recover their senses, they cannot of themselves waive the purchase; yet if, after recovering their senses, they agree to it, their heirs cannot set it aside. 2 Bl. Com. 291; and see 3 Day's R. 101. Their heirs may avoid the purchase when they die during their lunacy or idiocy. Co. Litt. 2 b.
7. - 2. It is a general rule that trustees 2 Bro. C. C. 400; 3 Bro. C. C. 483; 1 John. Ch. R. 36; 3 Desaus. Ch. R. 26; 3 Binn. Y. 59; unless they are nominally so, to preserve contingent remainders; 11 Ves, Jr. 226; agents; 8 Bro. P. C; 42; 13 Ves. Jr. 95; Story, Ag. 9; commissioners of bankrupts; assignees of bankrupts; solicitors to the commission; 6 Ves. Jr. 630, n. b.; auctioneers and creditors who have been consulted as to the mode of sale; 6 Ves. Jr. 617; 2 Johns. Ch. R. 257; or any other persons who, by their connexion with the owner, or by being employed concerning his affairs, have acquired a knowledge of his property, are generally incapable of purchasing such property themselves. And so stern is the rule, that when a person cannot purchase the estate himself, he cannot buy it, as agent for another; 9 Ves. Jr. 248; nor perhaps employ a third person to bid for it on behalf of a stranger; 10 Ves. Jr. 381 for no court is equal to the examination and ascertanment of the truth in a majority of such cases. 8 Ves. Jr. 345.
8. The obligations of the purchaser resulting from the contract of sale, are, 1. To pay the price agreed upon in the contract. 2. To take away the thing purchased, unless otherwise agreed upon; and, 3. To indemnify the seller for any expenses he may have incurred to preserve it for him. Vide Sugd. on Vend. Index, h. t.; Ross on Vend. Index, h. t.; Long on Sales, Index, h. t.; 2 Supp. to Ves. Jr. 449, 267, 478; Yelv. 45; 2 Ves. Jr. 100; 8 Coin. Dig. 349; 3 Com. Dig. 108.