The plaintiffs allege that they executed two promissory 'notes for $250.00 each, secured by purchase money mortgage. The uncontroverted evidence tends to show that defendant Hutchins discounted or “took up” these notes and now owns the same. They are *644past due. While the plaintiffs allege payment the jury resolved that issue against them.
So then it appears that defendant Hutchins holds two unpaid, past-due notes of plaintiffs which are secured by mortgage lien on land. Therefore there is no reason why the decree of foreclosure should not be affirmed.
While it is true that defendant failed to prove that the feme plaintiff joined in any contract to convey the locus to defendant, this allegation is made as a foundation for defendant’s claim for improvements and has no proper relation to the mortgage indebtedness. However, the notes are negotiable, and for this reason anyone could purchase without giving rise to the defense of voluntary payment. Hence, the absence of valid agreement to purchase does not defeat the defendant’s right to recover on the notes and have a decree of foreclosure to satisfy the amount found to be due thereon.
Among other assignments of error appearing in the record and relied upon by the appellants, is Exception No. 9, which reads: “The Court erred in not defining and explaining the law arising on the seventh issue relating to improvements made by defendant.” We are constrained to hold that this assignment of error is well taken. Among other ways, it is contended the charge fell short of the statute requiring “the judge to . . , state in a plain and correct manner the evidence .... and declare and explain the law arising thereon,” G. S., 1-180, his Honor failed to instruct the jury that the law cast upon the defendant the burden of proof of the issue. The issue read: “In what amount, if anything, is the defendant entitled to recover of the plaintiffs on account of improvements of the house on the 17-acre tract” ? Since the defendant was seeking a monetary recovery of the plaintiffs, it clearly follows that the burden of proving the right to such recovery was upon the party alleging such right and the amount sought to be recovered under this issue was alleged and sought to be proved by the defendant, and therefore the burden of showing the right to such recovery was upon the defendant. “ 'The rule as to the burden of proof is important and indispensable in the administration of justice. It constitutes a substantial right of the party upon whose adversary the burden rests; and, therefore, it should be carefully guarded and rigidly enforced by the Court. S. v. Falkner, 182 N. C., 793, and cases there cited.’ Hosiery Co. v. Express Co., 184 N. C., 478.” Coach Co. v. Lee, 218 N. C., 320, 11 S. E. (2d), 341. This omission in the charge was error.
We have examined the other assignments of error set out in the appellants’ brief but since there must be a new trial on defendant’s claim for improvements, it is not deemed necessary to comment further upon such assignments as they present no new questions of law and are not likely to occur again.
*645For the error mentioned, tbe plaintiffs are entitled to a new trial on 'defendant’s claim for improvements, and it is so ordered.
Partial new trial.