Though the law does not define in definite terms what a poison really is, it lays stress on the _malicious intention_ in giving a drug or other substance to an individual. It is a _felony_ to administer, or cause to be administered, any poison or other destructive thing with intent to murder, or with the intention of stupefying or overpowering an individual so that any indictable offence may be committed. It is a _misdemeanour_ to administer any poison, or destructive or noxious thing, merely to aggrieve, injure, or annoy an individual. For a working _definition_ we may state that a poison is a substance which, when introduced into or applied to the body, is capable of injuring health or destroying life. A poison may therefore be swallowed, applied to the skin, injected into the tissues, or introduced into any orifice of the body. II.--SALE OF POISONS; SCHEDULED POISONS The sale of poisons is regulated by various Acts, but chiefly by the Pharmacy Act, 1868, and by the Poisons and Pharmacy Act, 1908. Only registered medical practitioners and legally qualified druggists are permitted to dispense and sell scheduled poisons. They are responsible for any errors which may be committed in the sale of poisons. If a druggist knows that a drug in a prescription is to be used for an improper purpose, he may refuse to dispense it. The practitioner who carelessly prescribes a drug in a poisonous dose is not held responsible, but the dispenser would be if he dispensed it and harmful or fatal consequences followed on its being swallowed. When a dispenser finds an error in a prescription, it is his duty to communicate with the prescriber privately pointing out the mistake. A great responsibility rests on the medical man who does his own dispensing, as there is no one to check his work. If a doctor prescribes a drug with the intention of curing or preventing a disease, but that, contrary to expectation and general experience, it causes illness or even death, no responsibility can rest with the prescriber. It has to be proved that actual injury has been sustained by the complainant before an action for damages can be commenced, and that the plaintiff was free from all contributory negligence.