[In an ejectment suit of Groover against Niles, the plaintiff derived written title to the property in dispute from one Gamp, to whom defendant had conveyed by deed. Defendant offered to testify that the deed from him to Gamp was never delivered. Plaintiff objected, on the ground that Gamp was dead, and this contract was the cause of the present action. The court held the witness incompetent. The case having resulted adversely to the defendant, this ruling formed the substantial assignment of error.]