53-4-9. Mistake of fact defined.
Mistake of fact is a mistake not caused by the neglect of a legal duty on the part of the person making the mistake and consisting in:
(1)An unconscious ignorance or forgetfulness of a fact, past or present, material to the contract; or
(2)Belief in the present existence of a thing material to the contract which does not exist, or in the past existence of such a thing which has not existed.
Source: CivC 1877, §888; CL 1887, §3512; RCivC 1903, §1206; RC 1919, §821; SDC 1939, §10.0312.