1) Medical scientist 
• (n.) One versed in toxicology; the writer of a treatise on poisons.
(tok″sĭ-kol´ә-jist) a specialist in toxicology. developmental toxicologist one who specializes in developmental toxicology; see also teratologist.
Tox`i·col'o·gist noun One versed in toxicology; the writer of a treatise on poisons. 
Type: Term Pronunciation: tok′si-kol′ŏ-jist Definitions: 1. A specialist or expert in toxicology.
[n] - one who studies the nature and effects of poisons and their treatment
noun one who studies the nature and effects of poisons and their treatment