Louis Pasteur oversees injections of the child Joseph Meister with “aged” spinal cord allegedly infected with rabies virus. Pasteur uses the term “virus” meaning poison, but has no idea of the nature of the causitive organism. Although the treatment is successful, the experiment itself is an ethical violation of research standards. Pasteur knew he was giving the child successively more dangerous portions.
Pasteur: High Priest of Microbiology, ASM News 61, 1995. p.575 [pdf]