HTML definition, HyperText Markup Language: a set of standards, a variety of SGML, used to tag the elements of a hypertext document. It is the standard protocol for formatting and displaying documents on the World Wide Web. See more.
A toxicologist is a scientist or medical personnel who specializes in the study of symptoms, mechanisms, treatments and detection of venoms and toxins; especially the poisoning of people. To work as a toxicologist one should obtain a degree in toxicology or a related degree like biology, chemistry or biochemistry. Bachelor's degree programs in toxicology cover the chemical makeup of toxins and their effects on biochemistry, physiology and ecology.
Toxicity is a measure of the poisoning strength of a chemical. Chemicals that are only weakly toxic require large doses to cause poisoning. Strongly toxic chemicals only need small doses to cause poisoning. Toxicologists often use animal tests to determine whether small or large doses of a particular chemical cause toxicity. One such test measures the dose of a chemical that causes death to 50% of the animals being tested. This test is called the Lethal Dose 50 (LD 50). There is a tendency to think of chemicals in terms of those which are poisonous or toxic and those which are harmless.