An employment is terminated: (1) By expiration of its appointed term; (2) By extinction of its subject; (3) By death of the employee; or (4) By legal incapacity of the employee to act as an employee. Source: CivC 1877, § 1150; CL 1887, § 3773; RCivC 1903, § 1469; RC 1919, § 1093; SDC 1939, § 17.0402; SL 2008, ch 276 , § 27.