Opinion by

When an employee, after having the opportunity of becoming acquainted with the risks of his situation, accepts them, he cannot complain if subsequently injured by such exposure. By contracting for the performance of hazardous duties, he assumes such risks as are incident to their discharge from causes open and obvious, the dangerous character of which causes he has had *113opportunity to ascertain. On the other hand, where there are special risks in an employment of which the employee is not, from the nature of the employment, cognizant, or which are not patent in the work, it is the duty of the employer specially to notify him of such risks, and on failure of such notice, if he is hurt by exposure to such risks, he is entitled to recover from the employer in all cases where the employer either was cognizant or ought to have been cognizant of the risks: Wharton on Negligence, sec. 206. It may be, as the defendant’s counsel argue, that the defendant was not bound to provide a rope by which the machine at which the plaintiff worked could be quickly stopped. If the plaintiff had accepted service knowing that there was no such provision for his safety it might well be argued that the injury he received was within the scope of the danger which both parties contemplated as incidental to the employment. But having provided it, there was an implied obligation on the defendant not to aggravate the plaintiff’s risk by an omission to keep it in the condition in which under all the circumstances the plaintiff had a right to expect that it would be kept. Perhaps, if the defendant had removed the rope and the plaintiff had continued in his employment with knowledge of the increased risk, it could be urged that he accepted it; but it cannot be asserted that he accepted the risk of its becoming rotten and unfit for the purpose for which it was obviously intended. The principle has been thus stated: “ If a person undertakes to do an act or discharge a duty by which the conduct of another may properly be regulated and governed, he is bound to perform it in such a manner that those who are rightfully led to a course of conduct or action on the faith that the act or duty will be properly performed, shall not suffer loss or injury by reason of his negligence.” It is not too much to say that, presumably, the plaintiff entered and remained in the defendant’s employment in the faith that this appliance would be kept in reasonably safe condition. The learned trial judge correctly stated the duty of the defendant and the principle underlying it hi the following instructions: “ But the question is, did this defendant, having adopted this means of stopping the engine, it seeming to be the fact that there was no engineer at the engine continuously, did he, having adopted that means, and thereby certifying that that was a *114proper means, and we will assume for the purposes of this case that it was, exercise due care in seeing that that appliance was kept in order ? ” There was ample evidence to warrant the submission of this question to the jury, and to sustain their finding that if the rope had been in proper condition the machine could and would have been stopped before the injuries for which they awarded damages were caused.

This brings us to the question as to the liability of the defendant for the increased or additional injuries sustained by the plaintiff in consequence of the negligently defective condition of the appliance provided for stopping the machine, assuming that the plaintiff’s hand was caught in the rolls without negligence on his part or that of the defendant. Without entering into a discussion of the perplexing doctrine of proximate cause and its application to this case we affirm the proposition of the plaintiff’s counsel that, under the facts necessarily implied in the verdict, the proximate cause of these additional or increased injuries for which a recovery was permitted was the negligence of the defendant in maintaining an insufficient and unsafe appliance for the stopping of the machine in the event of the occurrence of such an accident, which under the circumstances it was the defendant’s duty to know might occur. Although this negligence was not the primary cause of the accident it was the efficient cause of the injuries. Though the plaintiff might have lost the use of his hand by the accident, there was evidence to warrant a finding that he would not have lost the use of his arm if the defendant had exercised due care. It was an accident likely to occur in the use of such a machine, and although it be conceded that it was not preventable it does not follow that the employer is not responsible for the consequences which were preventable by the exercise of ordinary care on his part. The difficulty in determining at what precise point the negligence of the defendant became the efficient cause, and of drawing the line between the injuries attributable to accident and those attributable to the defendant’s negligence was not so great in the present case as to be an insurmountable objection to the plaintiff’s recovery. There was evidence from which the jury could determine this dividing line with reasonable certainty. The difficulty was not greater than in apportioning damages among those severally *115liable- for tbe proportion of injury caused by the turning of mine water, culm, sawdust or the like in a flowing stream. The argument ab inconvenienti is not of sufficient force to hold each liaable for the whole injury, much less for not holding them liable at all. Neither is it of sufficient force to relieve this defendant from responsibility. As was said in Gould v. McKenna, 86 Pa. 297, “The difficulty of separating the damage from each cause may be great, but it does not change the nature of the tortious act of the defendant or relieve him from liability.” See also Little Schuylkill Nav. Co. v. Richards, 57 Pa. 142, Seely v. Alden, 61 Pa. 302, Bradford v. Downs, 126 Pa. 622, Gallagher v. Kemmerer, 144 Pa. 509, Nitro-Phosphate Co. v. London Docks Co., L. R. 9 Ch. D. 503, and Workman v. R. R. Co., 32 L. J. Q. B. 279.

It is unnecessary to discuss the several assignments of error in detail. The controlling questions raised by them have been touched upon. The case was well tried and there is no error in the record for which the judgment should be disturbed.

Judgment affirmed.