What standard of care must a physician bring to his task?

55 The standard of care that a physician must bring to his task was expressed by Sopinka J. in ter Neuzen v. Korn[2] in the following words (at para. 33): It is well settled that physicians have a duty to conduct their practice in accordance with the conduct of a prudent and diligent doctor in the same circumstances. In the case of a specialist, such as a gynaecologist and obstetrician, the doctor’s behaviour must be assessed in light of the conduct of other ordinary specialists, who possess a reasonable level of knowledge, competence and skill expected of professionals in Canada, in that field. A specialist, such as the respondent, who holds himself out as possessing a special degree of skill and knowledge, must exercise the degree of skill of an average specialist in his field: [authorities omitted]. The Plaintiff’s Case