What is the test for gross negligence in a medical malpractice case?

Duff, J. in Rex v. McCarthy, supra, is reported at p. 754 as follows: “Where the accused, having brought into operation a dangerous agency, which he has under his control (that is to say, dangerous in the sense that it is calculated to endanger human life), fails to take those precautions which a man of ordinary humanity and reasonably competent understanding would take in the given circumstances for the purpose of avoiding or neutralizing the risk, his conduct in itself implies a degree of recklessness justifying the description ‘gross negligence’.”