/ 9791041985265 MToxicology (τοξικὸν poison, and λόγος discourse, ) is that branch of medical science which treats of the nature, properties, and effects of poisons. It appears scarcely possible to give any definition of a poison which will bear a critical examination; insomuch that some have preferred to deal with the evil effects of any substance, that is poisoning, rather than with the substance itself, the so-called poison. Most medicines are poisonous in improper doses; and even common salt (chloride of sodium) has caused death. Dr. Guy defines a poison to be any substance which, when applied to the body externally, or in any way introduced into the system, without acting mechanically, but by its own inherent qualities, is capable of destroying life. A cherrystone may cause death by becoming arrested in the vermiform appendix, and thus producing peritonitis; boiling water may cause death also; but neither are poisons: the one acting mechanically, the other by its heat merely.