Forensic medicine is also called Medical Jurisprudence or Legal Medicine, and includes all questions which bring medical matters into relation with the law. It deals, therefore, with (1) crimes and (2) civil injuries.

1. A crime is the voluntary act of a person of sound mind harmful to others and also unjust. No act is a crime unless it is plainly forbidden by law. To constitute a crime, two circumstances are necessary to be proved—(a) that the act has been committed, (b) that a guilty mind or malice was present. The act may be one of omission or of commission. Every person who commits a crime may be punished, unless he is under the age of seven years, is insane, or has been made to commit it under compulsion.

Crimes are divided into misdemeanours and felonies. The distinction is not very definite, but, as a rule, the former are less serious forms of crime, and are punishable with a term of imprisonment, generally under two years; while felonies comprise the more serious charges, as murder, manslaughter, rape, which involve the capital sentence or long terms of imprisonment.

An offence is a trivial breach of the criminal law, and is punishable on summary conviction before a magistrate or justices only, while the more serious crimes (indictable offences) must be tried before a jury.

2. Civil injuries differ from crimes in that the former are compensated by damages awarded, while the latter are punished; any person, whether injured or not, may prosecute for a crime, while only the sufferer can sue for a civil injury. The Crown may remit punishment for a crime, but not for a civil injury.