The effect of the decisions upon this point is correctly summarized in 2 Jones, Evidence, (2d. ed.) s. 716, as follows: "Where a letter is read to charge a party, his answer is held to be admissible in reply, under the rule which admits the whole of a conversation or transaction." Among the numerous cases which support this conclusion, reference may be made to the following: Hoggson c. Co. v. Sears, 77 Conn. 587; Proctor v. Company, 145 Mich. 503; Hinton v. Welch, 179 Cal. 463; Guild v. More, 32 N.D. 432; Mooney v. Burgess, 142 Minn. 406; Gibson v. Lacey, 87 Ind. 202; Portsmouth Oil c. Co. v. Company, 195 Ala. 256; Tishomingo c. Co. v. Gullett, 52 Okla. 180. The general principle of completeness is based upon conceptions of substantial justice and fairness which are far more fundamental and important than the theory of incorporation by reference.

"It is not error for the trial court to refuse a requested instruction to the jury as to law that is fairly given, although in another form, in the general instructions." In Tishomingo Electric Light Power Co. v. Gullett, 52 Okla. 180, 152 P. 849, the court announced the rule in the 3rd paragraph of the syllabus as follows: "The refusal of the court to give instructions which properly state the law is not reversible error, if substantially the same proposition of law is stated in other instructions given, and where the charge of the trial court, as a whole, properly states the law."

The plaintiff in this case admits that defendant obtained peaceable and lawful possession of the property, but claims that possession is being unlawfully withheld from him by the defendant, Turnbaugh, who claims that he is lawfully in possession as agent of the Merchants' Produce Company. Under the general denial filed by the defendant, he is entitled to introduce any evidence that controverts any fact which the plaintiff is bound to prove in order to recover. Tishomingo Electric Light Power Co. Y. Gullett, 52 Okla. 180, 152 P. 849; City of Oklahoma City v. P. J. Hill et al., 4 Okla. 521, 46 P. 568; McKelvey v. Choctaw Cotton Oil Co., 52 Okla. 81, 152 P. 414. But plaintiff contends that it is not a legal defense that one is holding property as the agent of another, and cites in support thereof Luling v. Shepherd, 112 Ala. 588, 21 So. 352.

The defendant was entitled to introduce evidence under the general denial controverting any fact which the plaintiff was bound to prove in order to establish his cause of action. Robinson et al. v. Peru Plow Wheel Co., 1 Okla. 140, 31 P. 988; Tishomingo Electric Light Power Co. v. Gullett, 52 Okla. 180, 152 P. 849. Ditzler Dry Goods Co. v. Sanders, 44 Okla. 678, 146 P. 17, was an action for alleged wrongful discharge of a servant, and it was there held that the defense of a general denial put in issue the contract of employment and the question of a breach thereof. In Bey v. Reid, 31 Kan. 113, 1 P. 264, plaintiff and defendant had entered into a written contract whereby plaintiff employed defendant to serve as a clerk in the store or stores of plaintiff for a period of one year.