The deviation of man from the state in which he was originally placed by nature seems to have proved to him a prolific source of diseases.
Source: An Inquiry into the Causes and Effects of the Variolae Vaccinae, or Cow-Pox.
-- Edward Jenner, (May 17 1749-1823), English physician; He discovered and named the process of vaccination against smallpox, 1796; paved the way for the science of immunology.