This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
If a contract under seal is incomplete on its face, and some of its terms must be supplied by extrinsic evidence of the oral agreement of the parties, it is clear that such a contract cannot be said to be under seal. The principle is carried so far that even if blanks are purposely left in a sealed instrument and such blanks are, after delivery of the instrument, filled by one having parol authority to fill them, the instrument is without effect as an instrument under seal.1 This rule is very generally recognized where the instrument is so incomplete before the blanks are filled as to be without legal effect,2 but it is denied in some states where the instrument is merely incomplete before the blanks are filled, but is not wholly inoperative.3 The cases thus far discussed are those in which the contract is required by law to be under seal, and hence the real question is as to the validity of the contract as a sealed contract, since the oral contract, even if complete, does not comply with the requirements of the law. If, however, the contract is one which is valid if not under seal, it is not merged in a subsequent contract under seal if the latter is incomplete or invalid.4 Accordingly the validity of a prior simple contract is not affected by a subsequent defective contract under seal.
1See Sec. 1123.
2 See Sec. 1189.
3See Sec. 1189.
4 See Sec. 1354.
1 Hibblewhite v. M'Morine, 6 M. & W. 200 (disapproving Texira v. Evans, which is referred to in the opinion of the court in 1 Anst. 228) ; Ingram v. Little, 14 Ga. 173; 58
Am. Dec. 549; Mickey v. Barton, 194 Ill. 446; 62 N. E. 802; People v. Organ, 27 Ill. 27; 79 Am. Dec. 391; Basford v. Pearson, 9 All. (Mass.) 387; 85 Am. Dec. 764; Clark v. Butts, 73 Minn. 361; 76 N. "W. 199; Williams v. Crutcher, 5 How. (Miss.) 71; 35 Am. Dec. 422; Blacknall v. Parish, 6 Jones. Eq. (N.