In 1880, Griffith Evans, an army veterinary surgeon in India, made the seminal discovery that blood parasites - then universally considered benign - were pathogenic. Spurned by peers and colleagues, his conclusions from experiments with diseased horses were acknowledged by Koch and Pasteur, but it took many years before his achievement received general recognition.  The son of a farmer near Tywyn, Meirionnydd, Evans was commissioned as a veterinary officer in the Royal Artillery. He was first posted to Canada where, in his spare time, he qualified in medicine. An irrepressible adventurer, he visited North America during the Civil War, meeting Abraham Lincoln and touring the Union front line.  Evans's talent for engagement with people and cultures characterised his life in Canada and in India. During a long and productive retirement in north Wales, he immersed himself in local and national affairs. At his centenary in 1935, Evans received the accolades of his profession, community and family, dying peacefully in his hundredth year. Since that time, his name has faded into obscurity.