CHARACTERISTICS OF DIFFERENT POISONS Classification.—Poisons may be classified in many different ways, e.g., according to their chemical composition, to their action on the body, to their physical characters, etc.
The following is a convenient and simple classification.
I. Corrosive Poisons are those which destroy by direct action the tissues with which they come in contact. They are the mineral acids such as sulphuric, hydrochloric, nitric acids, etc ; the caustic alkalies such as caustic soda, caustic potash, ammonia, etc.; carbolic acid ; metallic poisons such as corrosive sublimate, zinc chloride, silver nitrate. These latter will be considered under irri tant poisoning. It should be remembered that corrosive poisons in diluted condition lose their corrosive effect and become irritants.
2. Irritant Poisons.—These poisons by their direct action on the mucous membrane set up inflammation. Examples are : oxalic acid and its soluble salts; arsenic compounds, antimony compounds; most of the metallic poisons in solution; phosphorus, bromine, iodine, boracic acid, etc.
3. Systemic Poisons which act on the nervous system or other important organs such as the heart, liver, lungs or kidneys without having any special irritant or corrosive effect. This group includes the majority of poisonous substances such as the vegetable poisons or their alkaloids, hydrocyanic acid, its salts, chloral, chloroform, alcohol, ether, hypnotic drugs such as veronal, sulphonal, etc. Also liver poisons such as those causing toxic jaundice, tetrachlorethane, trinitrotoluene, picric acid, etc., and renal poisons such as can tharides, turpentine, etc.
4. Gaseous Poisons such as chlorine, carbon-monoxide and coal gas, carbon-dioxide, etc.
5. Poisonous Foods such as mushrooms, shell fish and food con taminated with dangerous pathogenic bacteria.