_Rule in Leading Case of Lanphier v. Phipos._—In the case of Lanphier _v._ Phipos, 8 C. & P., 478, already cited, Chief Justice Tyndall enunciated the rule as to the degree of skill required of a physician or surgeon, which has been followed by all the courts since then. He said: “Every person who enters into a learned profession undertakes to bring to the exercise of it a reasonable degree of care and skill. He does not, if he is an attorney, undertake at all events to gain the cause, nor does a surgeon undertake that he will perform a cure; nor does the latter undertake to use the highest possible degree of skill, as there may be persons of higher education and greater advantages than himself; but he undertakes to bring a fair, reasonable and competent degree of skill. And in an action against him by a patient, the question for the jury is whether the injury complained of must be referred to a want of proper degree of skill and care in the defendant, or not. Hence he is never presumed to engage for extraordinary skill, or for extraordinary diligence and care. As a general rule, he who undertakes for a reward to perform any work is bound to use a degree of diligence, attention and skill, adequate to the performance of his undertaking; that is, to do it according to the rules of the art; _spondet peritiam artis_. And the degree of skill arises in proportion to the value and delicacy of the operation. But he is in no case required to have more than ordinary skill, for he does not engage for more.” _Physician Must Instruct Patient how to Care for Himself, etc._—A corollary of these rules is, that the physician must give proper instruction to his patient how to take care of himself, how to manage a diseased or injured member, when and how to take any medicines that may be prescribed, what diet to adopt, and that in case the physician fails to give these instructions he is liable for any injuries that result from this failure. Carpenter _v._ Blake, _supra_.