In a healthy person the violence necessary to prove fatal ought to be greater than in one diseased, and pathological conditions may be found _post-mortem_, which were pre-existent to the injury, _e.g._ degeneration of blood-vessels, aneurysm, valvular disease of the heart, phthisical cavities which may have bled, gastric ulcer which may have ruptured. Such conditions might influence the findings of a jury, as, for example, it is not always possible to form the opinion that death has been directly due to violence when signs of injury are slight; a man may receive a blow on the head while in the act of falling in a fight, and _post-mortem_ a cerebral hæmorrhage be found with diseased vessels, when it would be difficult to say with certainty that the hæmorrhage was directly caused by the blow or preceded it. 2. Indirect Fatal Complications.--In English law if death follow injury inflicted by a person within a year and a day, the assailant may be tried and punished; beyond that time the person is not held responsible for the death. The infective processes mentioned above may supervene at any time during the course of wounds with fatal result. Further, as a result of altered conditions left by injuries which in themselves have not proved fatal, and from the immediate effects of which the person has recovered, fatal complications may follow, _e.g._ a person may have received an abdominal wound which after healing may become the seat of hernia which may strangulate; or an injury to the spinal cord, which may cause death at a late date from bedsores and exhaustion. Septic Processes.--These may cause death at an early date according to their nature and virulence and the power of resistance of the person. In such cases the original injury need not have been dangerous to life. In other cases the infection may persist after the wound has healed, as infective endocarditis might conceivably do. Surgical Operations.--Should a surgical operation be considered necessary for the treatment of the injury or in order to save life, and the person dies after it, the prisoner will be held responsible for the death. This holds good if the operation has been done in good faith and performed with reasonable skill and care. If, however, it can be shown that the operation was unnecessary, or performed unskilfully and death resulted, the prisoner would not be held responsible unless it can be proved that the injury apart from the operation could have caused death, when the jury might convict. Where from improper treatment of an injury an operation is called for because of the improper treatment and the person dies, the prisoner would not be held responsible. The main points to be considered in reference to surgical operations for criminal injuries are: (1) The operation must be absolutely necessary. (2) The operator must have acted with reasonable skill and care.