The skill required is not an _absolute_ but a _relative_ qualification; and as such, therefore, always subordinated to whatever conventional standard of professional proficiency we may choose to adopt. Like morals, it may vary with times and places, or, if based upon representative intellects, it is clear that the ideal type selected must be one to which the majority, rather than the minority, of minds approximate [132]. A physician, when called upon to manage a case, is not required to apply the skill and care which could be applied by the perfect ideal physician, for the reason that from the limitation of the human intellect no perfect ideal physician exists in practice, and, from the limitation of human endurance, no perfect ideal physician, even if he existed, could watch a patient unintermittingly. But a physician, when called upon to manage a case, is bound to exercise the skill and vigilance which good and faithful physicians, under the circumstances in which he is placed, would exercise. If called upon in a country town, remote from the great centres of scientific activity, to attend to an exceptional case which requires immediate action, he is not liable if he does not employ those mechanisms which only a residence in such a centre of scientific activity would enable him to procure. On the other hand, a physician living in such a |61| centre is liable for negligence, if, when called upon in such a case, he does not use such mechanism, supposing its application to be advisable [133]. A physician and surgeon is bound to possess the ordinary skill, learning and experience of his profession generally at the time in similar localities, and with similar opportunities for experience [134]. A patient is entitled to the benefit of the increased knowledge of the day. The physician or surgeon who assumes to exercise the healing art is bound to be up to the improvements of the day. The standard of ordinary skill is on the advance; and he who would not be found wanting must apply himself with all diligence to the most accredited sources of knowledge [135].