by John Marshall Harlan, Wabash Railway Company v. McDaniels…
“ And to say, as matter of law, that a railroad corporation discharged its obligation to an employe-in respect of the fitness of co-employes whose negligence has caused him to be injured-by exercising, not that degree of care which ought to have been observed, but only such as like corporations are accustomed to observe, would go far towards relieving them of all responsibility whatever for negligence in the selection and retention of incompetent servants. ”
