May 16:
(1) (1845) Russian biologist and zoologist Ilya Ilyich Mechnikov was born. He is credited for discovering macrophages, which are essential for the body’s innate immune system.
(2) (1988) A report by the Surgeon General of the United States C. Everett Koop states that nicotine’s addictive properties are similar to those of heroin and cocaine.
(3) (2013) Human stem cells are successfully cloned in a lab.