Whenever the coroner, being himself a physician or surgeon, shall conduct a postmortem examination of the dead body of a person who came to his death by violence or casualty, and it shall appear to the county commission that such examination was necessary to ascertain the cause of such person’s death, the county commission may allow the coroner therefor an additional fee, not exceeding twenty-five dollars, to be paid as his other fees in views and inquests; but section 58.560 shall not be construed to apply to any such examination when made by the coroner himself.