None of the exceptions taken in this case can be sustained.
1. The defendant called two experts as witnesses, and then proposed to ask each of the experts called by the plaintiffs *144whether he considered his judgment as good as that of the two called on the other side. This question was properly excluded by the court. It was in effect an attempt to introduce the opinion of witn esses as to the value of the evidence of the defendant’s witnesses. It is not the province or duty of a witness to make such comparisons. He is to testify what -he knows, and the jury are to weigh the evidence.
2. It has been repeatedly decided in this commonwealth, that, when a claim is made upon the insolvent estate of a deceased person, founded upon a debt secured by mortgage, the creditor may prove his whole debt against the administrator, if he will give up his security ; but if he elects to retain his security, its value must be ascertained and deducted, and he can only prove the remainder. The value of the mortgaged property may for this purpose be fixed by consent of parties, or ascertained by a sale; or it may be determined by the jury before whom the cause is tried, who will then render a verdict for the amount due after deducting the estimated value of the security. The latter course was adopted in this case; and it is fully justified by authority. Amory v. Francis, 16 Mass. 308. Hooker v. Olmstead, 6 Pick. 481. Towle v. Bannister, 16 Pick. 255. In each of these ¿oses a similar course of procedure was approved by this court.
3. As the debt was not contingent, although payable in instalments, some of which were not due, the ■whole was properly allowed to be proved. This necessarily follows from the fact that all the liabilities of the estate of the deceased insolvent are to be ascertained once for all, in order to a just and equal distribution of the assets. If the creditor owning a debt, debitum in prcesenti, solvendum in futuro, were not permitted to prove it, he would be forever debarred from any participation in the estate. Aldrich v. Campbell, 4 Gray, 286.
4. The refusal of the court to grant a new trial is not the subject of exceptions. The presiding judge certifies that most of the grounds taken in support of that motion were not founded in fact. The trial proceeded by consent of parties, and it is too late, after a verdict, to object to defects in the declaration which might have been cured by amendment, if the objection *145had been seasonably taken. Gen. Sts. c. 129, §§ 11,12, 34, 41, 42, 79.
5. If the defendant has through accident or misapprehension allowed payments which she made after the decease of the intestate, and which she might have recovered back, to be deducted without objection from the plaintiffs’ claim, her only remedy is by an application to the superior court for a new trial or a correction of the verdict, if sufficient reason for either can be shown to exist. We cannot correct, on a bill of exceptions, an error to which no exception was in fact taken at the trial.
Exceptions overruled.