622.35  Party made witness.
  The oral evidence of the maker against whom the unwritten contract is sought to be enforced shall be competent to establish the same.
[C51, §2413; R60, §4010; C73, §3667; C97, §4628; C24, 27, 31, 35, 39, §11288; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §622.35]