Under the evidence adduced at the trial, the maintenance of the claim of the plaintiff (the appellee here) to the personal property sued for was dependent upon his sustaining the contention, which there was evidence to support that at the time of the attempted foreclosure of a mortgage of that property which he had given he had paid in full the debt secured by that mortgage, with the result that the foreclosure was unauthorized and ineffectual to bar his title or right to the property.
The court was not in error in admitting the testimony of the plaintiff as to the value of the property sued for and as to the value of its rental or hire. It appeared from his testimony that he was acquainted with the property in question and had had opportunities of knowing the price at which that and similar property had been sold and rented. This was enough to qualify him to give his estimate or opinion as to the values in*453quired about. To establish the competency of a witness to testify as to such matters, it is not required to be shown that he had had such special experience or training as to entitle him to be called an expert. — Hodge, et al. v. Rambo, 155 Ala. 175, 45 South. 678; Montgomery-Moore Mfg. Co. v. Leith, 162 Ala. 246, 50 South. 210; Hooper v. Dorsey, 5 Ala. App. 463, 58 South. 951.
On the cross-examination of the plaintiff, the facts were brought out that he had executed a mortgage of the property sued for, which the defendant introduced in evidence, and that the mortgagee, in response to the plaintiff’s written request, had furnished him a statement of the account secured by the mortgage. On the plaintiff’s redirect examination, after he had introduced in evidence the statement of account about which he had testified on his cross-examination, which statement showed a balance owing to the mortgagee on the mortgage debt, and had testified that the mortgagee had advertised and sold the property under the mortgage after the debt secured by it had been fully paid, he was ashed by his counsel to state whether or not the account which he had introduced in evidence was correct, and, if not, to state in what particulars it was incorrect. The defendant’s objection to this question was overruled. It is insisted in the argument of the counsel for the appellant that the objection should have been sustained on the grounds stated in support of it; that, the plaintiff himself having introduced the account in evidence, he could not be permitted, to elect to be bound by such parts of it, as might be favorable to him and to disaffirm such parts of it as might be unfavorable to him; and that, by introducing it in evidence without qualification or a statement of his purpose to contest any of its items, he had estopped himself to deny the correctness of the account in any particular. The rule that, *454where an account is made out with debits and credits and presented to the debtor, he cannot claim the credits without submitting to the debits, cannot be so applied as to prevent the debtor from proving that certain charges shown against him in that statement are incorrect, where there is evidence of the payments made by the debtor other than that furnished by the creditor’s admissions contained in his statement. — Loventhal & Son v. Morris, 103 Ala. 332, 338, 343, 15 South. 672. In the present case the plaintiff: did not have to rely on the statement of the account furnished to him by the mortgagee to prove the payments which he had made on the mortgage, as his testimony was to the effect that that statement contained a correct list of the payments he had made. In this situation there was nothing in the mere fact of his introducing that statement in evidence to preclude his proving that some of the charges against him were incorrect. The defendant was in no position to sustain a claim that the plaintiff, by introducing the statement of account in evidence, estopped himself to raise any question as to its correctness.' There is no room for a claim that the defendant, or any. one with whom he was in privity, relied upon that conduct with the result of changing his position or taking any action to his prejudice, as the introduction of the account in evidence was almost immediately followed by the offer of the plaintiff to prove the incorrectness of some of its charges against him. One who claims that another has" estopped himself by his conduct cannot sustain such claim without showing that he relied on that conduct and was induced to act or to omit action on the faith of it. — Huntsville Elks’ Club v. Garrity-Hahn Building Co., 176 Ala. 128, 57 South. 750; 16 Cyc. 734. This essential element of an estoppel was lacking. The defendant could not have been misled to his prejudice *455by the failure of the plaintiff, at the time he introduced the mortgagee’s statement' of the account in evidence, to express his purpose to contest the correctness of it. The bringing and prosecution of the suit for the property covered by the mortgage indicated that the plaintiff did not admit that there had been a valid foreclosure of it. An impression on the part of any one that the plaintiff, by introducing in evidence the mortgagee’s statement of the account, was intending to affirm the correctness of that statement, could have been but momentary, as this action was closely followed by the plaintiff’s offer of testimony to prove the incorrectness of some of the debtit items in that statement. The course pursued by the plaintiff in the introduction of his evidence in this connection amounted to his first disclosing upon what claim the mortgagee had based his contention that a balance remained due on the mortgage debt, so as to entitle him to foreclose, and then adducing evidence going'to prove that the credits to which the plaintiff, the mortgagor, was entitled amounted to more than the aggregate of the sums with which he was properly chargeable, so that nothing was in fact owing on the mortgage debt when the sale under the power contained in the mortgage was made. The defendant could not have been harmed by the failure of the plaintiff to mate announcement of his purpose to offer such testimony when he introduced the mortgagee’s statement in evidence. The plaintiff had done nothing to mate the statement of the accoulnt conclusively binding upon him, and the court did not err in permitting him to controvert it by evidence of its incorrectness. '
There was evidence tending to prove that the account as rendered by the mortgagee to the plaintiff became a stated one. But whatever presumption of the correctness of that statement may have been raised by *456the plaintiff’s failure to controvert it promptly was a rebuttable one, and he was entitled to prove that any admission of his that might be implied from his silence was unsupported by a consideration, in that as a matter of fact no balance was owing on the mortgage debt at the time of the foreclosure. — Rice v. Schloss & Kahn, 90 Ala. 416, 7 South. 802; First National Bank of Talladega v. Chaffin, et al., 118 Ala. 246, 24 South. 80. The mortgage itself provided for payments to be made on it by the mortgagor supplying lumber to the mortgagee at the market price for such lumber prevailing when the orders for it were given, and the payments which were made on the mortgage debt were made in this way. The plaintiff in his testimony pointed out a number of charges against him shown by the mortgagee’s statement of the account which were not authorized by the terms of the mortgage or by any other agreement, express or implied, to which the plaintiff was a party. The aggregate of these charges which, according to the plaintiff’s testimony, were unauthorized, amounts to more than the balance shown by the mortgagee’s statement. It is contended in the argument of the counsel for the appellant that the plaintiff’s testimony as to these disputed charges against him disclosed such a lack of knowledge of the facts upon which they were based as to justify the court in putting aside that testimony as unworthy of consideration or of submission to the jury. We cannot concur in this view. The statement itself disclosed the nature of the mortgagee’s claims upon which the charges in question were based. For the mortgagor to controvert the correctness of these items it was not necessary for him to know more about them than that they were not authorized either by the terms of the mortgage or by any other agreement or transaction to which he was a party. Under *457the evidence in the case it was a question for the jury whether or not anything was owing on the mortgage debt at the time the foreclosure sale was made. The defendant was in no position to claim that he was misled by the plaintiff’s conduct, as the latter appeared at the foreclosure sale and gave public notice that any one who bought at it would buy a lawsuit.
Under the evidence in the case there was no room for the controversy as to the property sued for having-belonged to the plaintiff. The defendant set up no claim to it except under a foreclosure of a mortgage of it which had been given by the plaintiff. In this situation it was plainly incumbent upon the defendant to sustain by proof any items embraced in the claim for the payment of which the mortgage was foreclosed which were not authorized by the mortgage itself. Only by the consent of the mortgagor could the mortgage stand as security for a debt or claim not- mentioned in it, and the party claiming that there was such consent had the burden of sustaining such claim by proof. Charge 1 given at the plaintiff’s request imported no more than this, and the court was not in error in giving it.
What already has been said is deemed sufficient to support the conclusion that the proposition stated in charge 2 given at the request of the plaintiff is one which, under the evidence in the case, the court could properly give in charge to the jury.
The fault in charge 1 requested by the defendant in instructing the jury that if they believed the evidence they must find for the defendant under the first count of the complaint, instead of instructing them that in such event they should not find for the plaintiff, or should not find against the defendant on that count, was enough to justify the court in its refusal to give it. *458—Goldstein v. Leake, 138 Ala. 573, 36 South. 458; Key v. Goodall, Brown & Co., 7 Ala. App. 277, 60 South. 986. But, aside from this fault, the claim made in behalf of the defendant in reference to that charge cannot be sustained. That claim is that the plaintiff was not entitled to recover on the count in detinue because he had not, before bringing the suit, made demand for the property sued for. If such demand is necessary in any case to authorize a recovery in detinue, some of the evidence tended to prove that this is not such a case, as there was evidence going to prove that the defendant acquired possession of the property wrongfully, having no authority to take it except such as was conferred by a sale to him by a mortgagee who had not acquired a right to the possession of the property. Under that evidence a demand was not necessary to make the defendant’s detention unlawful. Even if the defendant had rightfully acquired possession of the property, it seems the plaintiff’s failure to demand it before bringing suit would have affected, not his right to recover the property itself, but only his right to recover damages for the detention of it. — Vaughn v. Wood, 5 Ala. 304; Daniel Bros. v. Jordan & Son, 146 Ala. 229, 40 South. 940; Black v. Slocumb Mule Co., 8 Ala. App. 440, 62 South. 308; 14 Cyc. 252, 262.
What has been said disposes of the assignments of error which counsel for the appellant have undertaken to support by argument.
Affirmed.