 This included a lavish use of heroin and morphia that may have constituted mercy killing, but he probably cared for his patients in the way he thought best.An editorial in a medical journal following the case suggested that the publicity it caused might hamper medical discretion, claiming the use of opiates in terminal cases was essential.Devlin's formulation of the double effect principle has been approved by the House of Lords and generally by many other legal and medical commentators, as it is in line with the legal doctrine of causation, that the disease which was beyond treatment was the true cause of death.