Opinion by

In the present case the contract for the sale of the Allison Mine contemplated the conveyance of about 325 acres of available coal, but when the contract was made both parties were aware of the fact that this was only an estimate, and it was therefore agreed that the coal should be surveyed, in order to determine accurately the amount of acreage. If it fell short of the stipulated amount, deduction was to be made from the purchase price at the rate of $200 per acre, and if it overran, the surplus was to be paid for at the same rate. If this survey had been made before the delivery of the deed, and the payment of the purchase money, there could have been no question whatever of the right to make deduction for the deficiency in the amount of the coal. But by reason of the fact that a deed was prepared and delivered by the vendors, and the purchase money was paid to them before the surveying was done, the appellants contend that they are released from any obligation to make good the amount of coal stipulated for, as the basis of the contract. As the trial judge says, if the original contract stood alone, either party desiring to have the benefit of the survey and adjustment of the acreage, must *544have made application therefor, prior to the passing of the deeds and the payment of the price. But for reasons satisfactory to themselves, the parties to the agreement chose not to delay the entire settlement until the surveys could be made, but instead adjusted between themselves everything but the amount of the acreage, and that was held open by the execution of a settlement certificate by the defendants in which it was expressly agreed that such adjustment as might be necessary upon the property conveyed being surveyed should be held open for future settlement. Upon this express condition then, the deed, bond, bill of sale, certificate, etc., were delivered and the purchase money paid. The trial judge, speaking. of the' original contract and these papers, says in his charge to the jury, you will observe that they “ are all practically the same as if they were one paper, and part of these papers is that that survey shall go on past the payment of the money. That is practically the only matter in this case that is very important,” and he went on to say that his interpretation of the papers required him to instruct the jury that the settlement certificate required and contemplated a survey to be thereafter made, and that the parties were to pay to each other whatever the result of that survey might show to be due.

Unquestionably, the trial judge was right in his construction of the language of the settlement certificate. It is contended, however, by counsel for appellants that as the settlement certificate was not set up in the statement of claim the plaintiff was not entitled to prove it, or offer it in evidence as a basis of recovery in this suit. The declaration was no doubt defective in this respect, but as the cause of action here was the deficiency in the amount of the coal which was to have been conveyed under the contract, and as the effect of the settlement certificate was only to extend the time for ascertaining the amount of the coal, and thus to preserve the rights of the parties in this respect under the contract, it cannot be said to change in any way the cause of action. It would, therefore, have been entirely proper for the plaintiff at the trial to have moved to amend the declaration, and for the court to have entertained the motion. The propriety of such action is fully discussed in Erie City Iron Works v. Barber, 118 Pa. 6. And *545this court there further said (p. 19): “ After a trial on the merits, no defect of pleading which could have been raised by a demurrer will be fatal to the judgment, unless it is shown to have injuriously affected the trial. The proper amendment will be considered to have been made. This is the outgrowth of the policy which has prevailed in practice in the allowance of amendments. The effect of our statutes has been to give more prominence to the trial of the cause had on its intrinsic merits, in the interest of a rational and speedy administration of justice, than to the exact and precise observance of the artificial forms originally devised for this purpose.” In the present case the defendants had, of course, full knowledge of the settlement certificate, having executed it themselves, and they refer to it in their affidavit of defense as providing the method by which they were to be paid the purchase money. If the settlement certificate was rightfully admitted as evidence, and we think it was, then it shows clearly by its terms a recognition by the parties of the right to have the survey made, after the settlement, and adjustment of all other matters was made under the original contract. This method was a construction by the parties as between themselves of the terms of the original contract. The terms of the settlement certificate not only provided for extending the time for the survey, but the subsequent conduct of the parties, in selecting surveyors and meeting at the mine to survey the coal and determine the acreage, all goes to show ratification of this feature of the agreement. As we said in Sherman v. Dental Mfg. Co., 202 Pa. 446, “ the parties themselves thus gave a practical demonstration of their mutual understanding of the agreement, which neither one can now be allowed successfully to dispute.” It is true that one of the defendants tried to break the force of this acquiescence in the arrangement for the survey by stating that he did not regard himself as called upon, under the contract, to make the survey and calculation. But this objection does not seem to have been made until after a dispute as to the method of the calculation had arisen. We see no error in the refusal by the court below to attach any weight to the testimony of a conversation between one of the defendants and the attorney for the purchasers, at the time the contracts were signed, to the effect that the price per acre fixed for the coal was a mere *546formality. Even if the testimony was deemed sufficient in itself to go to the jury to vary the terms of the written contract, it certainly should not have been submitted for that purpose after the contract had been expressly recognized and ratified by the settlement certificate of September 27, 1899. There is no merit in the contention that the court below should have given binding instructions for the defendants on the ground that the surveys were not properly made. That was for the jury. The facts were fully developed by the testimony, and there was ample from which the jury might find whether or not there was a deficiency in the amount of available coal contracted for. Defendants had no survey made, and presented nothing to impeach the correctness of the figures of plaintiff’s witnesses. The matter was properly submitted to the jury, and that body evidently used some discrimination, for the verdict was very much smaller than would have been justified by the evidence.

Our examination of the whole case leads us to the conclusion that it was fully and fairly tried upon the merits, and the judgment is affirmed.