He was the Anthony N. Brady Professor and chairman of the department of pathology at the Yale School of Medicine.
[6] He was internationally noted for his work in cancer research which led to breakthroughs in tissue transplantation.
[7] In the 1950s and 1960s he gained public prominence as a very vocal skeptic of then-new theory that there was a connection between smoking and lung cancer.
[8][9] In 1957 he testified to a Congressional committee investigating the health effects of smoking that the apparent association between smoking and lung cancer was purely statistical and that there was no evidence that the one caused the other.
He later wrote that "The evidence from both approaches, statistical and experimental, does not appear sufficiently significant to me to warrant forsaking the pleasure of smoking.