Sec 200

If a non-specialist makes a bargain with a specialist as to a topic within the range of the latter's duties, the same knowledge of the law will not be imputed to both. A lawyer, for instance, making a bargain with a client, will be chargeable with a special knowledge of the law bearing on the topic of the bargain, while the client would be chargeable with no such special knowledge ; and a skilful engineer, contracting with a person ignorant of engineering, would be chargeable with a knowledge of the law bearing on engineering when no such knowledge would be imputable to the other party. So when the question comes up whether a party to a contract is liable for not knowing what it was his duty to know, his liability is measured by his duty. If he claimed to be a specialist, he should have known what a specialist of that class ought to know ; if he claimed only to be a non-specialist, it was neces. sary for him only to have had the knowledge usual to non-specialists.1 When the question of culpa in contrahendo arises, this distinction is of peculiar importance.2

Sec 201

But whatever we may think as to the foregoing distinctions, it is plain that if one party avails himself of another's ignorance of law to impose upon him, the latter may invoke the aid of a court of equity for his protection.3 This has been held to be the case with respect to fraudulent representations by a specialist as to the legal effect of a document.4 And there is strong authority to the effect that in such case not only will a contract thus induced be rescinded by a court of equity, but that a court of law will refuse to sustain a suit on such a contract.5

Special knowledge not presumed in non-specialist.

Error of law when acted on fraudulently avoids.

1 Wh. on Neg. sec 414, 510, 520 ; Wh. on Ev. sec 1241.

2 Infra, sec 1043.

3 Infra, sec 232 et seg.; Cooper v. Phibbs. L. R. 2 H. L. C. 149 ; Wheeler v. Smith, 9 How. 55 ; Jordou v. Stevens, 51 Me. 78; Freeman v. Curtis, 51 Me. 140; Woodbury Bank v. Ins. Co., 31 Conn. 517; Whelen's App. 70 Penn. St. 425 ; Tyson v. Tyson, 31 Md. 134; Met. Bank v. Godfrey, 23 111.

579 ; Dagas v. Donaldsonville, 33 La. An. 671.

4 Edwards v. Brown, 1 C. & J. 312 ; Hirschfield v. R. R., L. R. 2Q. B. D. 1; see distinction stated, infra, sec 259.

5 Story on Cont. sec 526; 2 Evans's Pothier on Oblig. 409, 437; May v. Coffin, 4 Mass. 346 ; Haven v. Foster, 9 Pick. 112. As to signatures fraudulently induced, see supra, sec 185.