Animals have served humans in their search for drugs in a number of ways Hormonal substances, such as thyroid (甲状腺) extract, insulin,and pituitary(脑垂体) hormone obtained from the endocrine glands of cattle, sheep, and swine. The use of animals in the production of various biologic products, including serums antitoxins. and vaccines• Animals have served humans in their search for drugs in a number of ways. • Hormonal substances, such as thyroid （ 甲 状 腺 ） extract, insulin, and pituitary（脑垂体）hormone obtained from the endocrine glands of cattle, sheep, and swine. • The use of animals in the production of various biologic products, including serums, antitoxins, and vaccines