Joseph McKenna

“ As we deduce from the duty of Di Donato his employment to have been in interstate commerce, we have no occasion to consider what presumptions might be indulged if his employment were not thereby established, whether for or against intrastate commerce. ”

“ Industrial Accident Comm'n, supra, Di Donato's duty had other purpose than the prevention of a disaster to a particular train. It had purpose as well to the condition of the tracks and their preservation from disorder and obstructions. This service and the other service cannot be separated in duty and responsibility. It is to be remembered that not only the remedy of one employee is involved in a particular duty but that other employees and other remedies are to be considered as well and the defenses to them, and that behind them are the respective powers that may have ordained them. ”

“ The service of a flagman concerns the safety of both commerces and to separate his duties by moments of time or particular incidents of its exertion would be to destroy its unity and commit it to confusing controversies. ”