I look upon a good physician, not so properly as a servant to nature, as one, that is a counsellor and friendly assistant, who, in his patient's body, furthers those motions and other things, that he judges conducive to the welfare and recovery of it; but as to those, that he perceives likely to be hurtful, either by increasing the disease, or otherwise endangering the patient, he thinks it is his part to oppose or hinder, though nature do manifestly enough seem to endeavour the exercising or carrying on those hurtful motions.