When personal injury or death is caused to an employee by an accident arising out of and in the course of his employment, of which injury the actual or lawfully imputed negligence of the employer is the natural and proximate cause, he, or in case of death, his personal representative, for the exclusive benefit of the surviving spouse and next of kin, shall receive compensation by way of damages therefor from the employer; provided, that the injury or death was not caused by the wilful misconduct of the employee or was not due to misconduct on his part, as defined in Section 25-5-51.