Thomas Henry Huxley was a biologist and educator in the England of 19th century. He was called "Darwin's Bulldog" due to his support of Charles Darwin's theory of evolution.
Being a good friend of his, the First Doctor attended one of his speeches at the Royal College of Surgeons in 1968, bringing with his Ian Chesterton, Barbara Wright and Vicki Pallister. Later, Huxley helped the team fight a colony of Zarbi in the underground of the city. (COMIC: Prisoners of Time)