P is dead if and only if P's heart and lungs aren't fuctional.
P is dead if and only if no part of P's brain is functional.
P is dead if and only if P's cerebral cortex isn't functional. The respirator was invented and perfected. The first heart transplant was performed. The Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death published its report in the Journal of the American Medical Association . What Did and Didn't Follow.