He accepted an offer to give substitute lectures at Harvard on history, for a professor who had gone abroad for his health. This he continued, speaking for any absentee on any subject, and tutoring rich laggards for a consideration. Good boys, low on phosphorus, used to get him to start their daily themes, and those overtaken in the throes of trigonometry he often rescued from disgrace.
Darwinism was in the saddle. Asa Gray was mildly defending it. Agassiz stood aloof, clinging to his early Swiss parsonage teachings, and the Theological Department marched in solid phalanx and scoffed and scorned. Yale, always having more theology than Harvard, threw out challenges. Fiske had saturated himself with the ideas of Darwin and Wallace, and his intellect was great enough to perceive the vast and magnificent scope of "The Origin of Species." He prepared and read a lecture on the subject, all couched in gentle and judicial phrase, but with a finale that gave forth no uncertain sound.
The Overseers decided to ask Fiske to amplify the subject and give a course of lectures on the Law of Evolution.
The subject grew under his hands and the course extended itself into thirty-five lectures, covering the whole field of natural history, with many short excursions into the realms of biology, embryology, botany, geology and cosmogony.
Fiske was made assistant librarian at a salary of one thousand dollars a year. It was not much money, but it gave him a fixed position, with time to help the erring freshman and the mentally recalcitrant sophomore handicapped by rich parents. For seven years Fiske held this position of assistant librarian, and hardly a student at Harvard during those years but acknowledged the personal help he received at the hands of John Fiske. Knowledge consists in having an assistant librarian who knows where to find the thing.
Fiske's thirty-five lectures had evolved into that excellent book, "Outlines of Cosmic Philosophy." The public were buying it.
Evolution was fast taking its place as a fixed fact. And John Fiske was moving into public favor on the flood-tide. There were demands for his lectures from various schools, colleges and lyceums, throughout the United States.
He resigned his position so as to give all his time to writing and speaking. And Harvard, proud of her gifted son, elected him an Overseer of the University, which position he held until his death. John Fiske died in Nineteen Hundred One, suddenly, aged fifty-nine.
ext to the originator of a great thought is the man who quotes it," says Ralph Waldo Emerson. Next to the discoverer of a great scientific truth is the man who recognizes and upholds it. The service done science by Fiske is beyond calculation. Fiske was not a Columbus upon the sea of science: he followed the course laid out by others, and was really never out of sight of a buoy. He comes as near being a great scientist, perhaps, as any man that America has ever produced.