“ It had been his intention to reserve them for mature revision, but an attempted piracy compelled him to hasten their publication, and they appeared in 1894 under the title of The Ascent of Man. Their object was to vindicate for altruism, or the disinterested care and compassion of animals for each other, an important part in effecting “the survival of the fittest,” a thesis previously maintained by Professor John Fiske. ”

“ In 1877 he became lecturer on natural science in the Free Church College, which enabled him to combine all the pursuits for which he felt a vocation. His studies resulted in his writing Natural Law in the Spiritual World, the argument of which was that the scientific principle of continuity extended from the physical world to the spiritual. Before the book issued from the press (1883) , a sudden invitation from the African Lakes Company drew Drummond away to Central Africa. ”