In these rules Dr. Ewell regards chiefly what conduct the courts of justice will sustain. It is evident that the Doctor is never entitled to run up his bill without any benefit to his patient; where there is no service rendered at all, there can be no claim to compensation. Still it is not necessary that actual benefit has resulted to the patient; it suffices for the claim to the fee that measures have been taken with a view to such benefit. Even when no physical advantage can reasonably be hoped for from the visit, the consolation it affords the patient and his friends may render those who are to bear the expense fully willing that it should be often repeated and, of course, charged on the bill. Provided care be taken that they understand the situation, no injustice is done them. "_Scienti et consentienti non fit injuria_" is a good moral maxim. II. We have said that the rights conferred on the physician by the state are conditioned on his performing certain duties. He owes the same duties to his patients in virtue of the contract, explicit or implicit, that he makes with them by taking the case in hand. Under ordinary circumstances, neither the state nor the patients can oblige him to exercise his profession at all; but, if once he has taken a case in hand, he can be justly held not to abandon it till he has given his patient a fair opportunity of providing another attendant; even the fear of contagion cannot release him from that serious obligation. The duties arising from the physician's twofold contract, with the state and with his patients, are chiefly as follows: 1. He must acquire and maintain sufficient knowledge of his profession for all such cases as are likely to come in his way. No Doctor has the right to attempt the management of a case of which he has not at least ordinary knowledge. In matters of special difficulty, he is obliged to use special prudence or ask for special consultation. The courts justly hold him responsible for any serious injury resulting from gross ignorance; in such cases they will condemn him for malpractice. I would here remark that, in an age in which the science of medicine is making such rapid progress, every Doctor is in duty bound to keep up with the improvements made in general practice, and in his own specialty if he has one. 2. A second duty is that of proper diligence in treating every single case. Many a patient suffers injury to health or even loses his life in consequence of a Doctor's neglect. Gross negligence is an offence that makes him punishable by the court, if it results in serious injury. But even if such injury cannot be juridically proved, or has been accidentally averted, the moral wrong remains and is to be settled with the all-seeing Judge. Still, in ordinary ailments, no one is obliged to take more than ordinary trouble.