Aristotle ( Î ` Ï Î Ï Ï Î Ï Î Î '' Î Ï ) ( 384 -- 322 BCE ) and Erasistratus ( 304 -- 258 BCE ) were some of the first people to try out experiments on living animals . Aristotle ( Î ` Ï Î Ï Ï Î Ï Î Î '' Î Ï ) ( 384 â `` 322 BCE ) and Erasistratus ( 304 â `` 258 BCE ) were among the first to perform experiments on living animals .