I shall endeavour still further to prosecute this inquiry, an inquiry I trust not merely speculative, but of sufficient moment to inspire the pleasing hope of its becoming essentially beneficial to mankind.
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.