Such a measure of care, prudence, and assiduity as persons of unusual prudence and discretion exercise in regard to anyand all of their own affairs, or such as persons of ordinary prudence exercise in regardto very important affairs of their own. Railway Co. v. Rollins. 5 Kan. 180; Litchfield v.White, 7 N. y. 438. 57 Am. Dec. 534: Rev. Codes N. Dak. 1S99,