his consent, and that as there was no privity of contract established between the plaintiff and defendant, without such privity, the possession and use of the property will not support an implied contract to pay for it. 2. In C v. R, 15 Mass. 387, R was sued by the assignee of a note held not negotiable on account of a contingency upon which payment was made to depend. It was held that the assignee of such a common law chose in action could not maintain an action upon it in his own name.

3. In V v. H Ins. Co., 14 Conn. 141, the plaintiff brought suit by attachment against one M, attaching a debt claimed to be due to him from the defendant upon a policy of insurance. The defendant company resisted payment on the ground of an assignment of the policy to X. It was found that no notice of the assignment had been given to the defendant until long after the attachment. The defense was held not to prevail, and the rule laid down that in order to perfect an assignment of a chose in action, as against bona fide creditors and purchasers without notice, notice of such assignment must be given to the debtor within a reasonable time; and, unless such notice is given, creditors may attach and acquire a valid lien, and others may purchase the debt and gain a title superior to that of the first assignee.

4. In A v. B, 127 U. S. 379, the plaintiff was the assignee of a contract for the delivery of ore in 100-ton lots for smelting. The price to be paid for the ore was to be ascertained by an assay to be made after delivery. From delivery until the price was thus ascertained and paid the defendant had no security for payment except in the character and solvency of those who received the ore. The court held that such a contract is not assignable, quoting the familiar phrase of Lord Denman, "You have the right to the benefit you anticipate from the character, credit, and substance of the party with whom you contract," and distinguishing the contract from a simple agreement to pay money, or to deliver goods, which is assignable.

SIR WILLIAM BLACKSTONE (1723-1780)

An English jurist, educated at Pembroke College, Oxford. Having made a choice of the law, he was entered in the Middle Temple in 1741, and called to the bar in 1746. He is the author of Blackstone's Commentaries, an exposition of the common law. This treatise is written as four books (published in two volumes), dealing respectively with rights of persons and things, and public and private wrongs. He was by no means a great jurist and his writings are not accepted by lawyers as of great legal weight, but they have rendered much the same service to educated society of England that the Institutes did to Rome and the students of the civil law.

67. Introduction. Under previous sections we discussed, first, the manner of forming a contract and the elements that are essential; and, second, the operation of the contract, those whom it affected, and those who might acquire rights or assume liabilities under it. We are now to discuss the rules that are followed in explaining the meaning of the contract-how we prove the contract and determine what it means. This section will be dealt with under two heads: (1) proof of contract; and (2) construction of contract.

68. Proof of Contract. 1. Oral. When the contract is formed orally, the terms of the contract can only be established

by means of witnesses, parties who have knowledge of the agreement.

2. Written. The existence of a written contract is established by producing the writing. It is the evidence of the intention of the parties and must be produced unless lost or destroyed, in which case its terms must be established by parol evidence. If the contract is partly written and partly printed, as is usual in business papers, and there is an inconsistency, the written parts prevail.

3. Sealed. The existence of a sealed instrument also is es- . tablished by the production of the writing. A parol contract depends upon a consideration for its validity, while a sealed contract depends upon its form. In the former the consideration must be proved; in the latter it is presumed. The former is the evidence of the contract, while the latter is the contract.

While parol evidence is not competent to "change, vary, or contradict" the terms of a written contract, it is always permissible to deny the force and validity of such a contract. It may be shown that the instrument was executed through mistake, fraud, duress, without consideration, or by an incompetent party.

Oral evidence is also admissible where the submitted agreement is not complete. This must not vary the writing, but must supplement it. It is also permissible and sometimes necessary to resort to parol evidence to establish either the identity of the parties or the subject matter.

69. Usage of Trade. Frequently it is necessary to ascertain the usage or custom of trade in order to determine the true meaning of a contract. In commerce words frequently have a technical meaning aside from their ordinary signification. This technical meaning may be established by parol evidence. In a celebrated English case, in the transfer of a large number of rabbits, it was contended that the word "thousand" meant in that trade 100 dozen, or 1,200. It was so established by parol evidence. So, likewise, has it been shown that "thousand" meant seven hundred, a day but 10 hours, and so on.