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

In Jones v. Livox Quarries Ltd., [1952] 2 Q.B. 608, Denning, L.J., said at page 165: Although contributory negligence does not depend on a duty of care, it does depend on foreseeability. Just as actionable negligence requires the foreseeability of harm to others, so contributory negligence requires the foreseeability of harm to oneself. A person is guilty of contributory negligence if he ought reasonably to have foreseen that, if he did not act as a reasonable, prudent man, he might be hurt himself; and in his reckonings he must take into account the possibility of others being careless.