[2] George Griffith, a teacher at Harrow, encouraged and aided him in the pursuit of natural science, a taste for which, especially geology, he had acquired from his mother.

The research work which he began there contributed in an important degree to his election as a Fellow of Trinity in 1874; and also gave him the material for a series of papers (published as a monograph in 1878) on the Elasmobranch fish, which threw new light on the development of several organs in the Vertebrates, in particular of the uro-genital and nervous systems.

This book displayed a vigorous scientific imagination, controlled by a logical sense that rigidly distinguished between fact and hypothesis, and it quickly won wide recognition, both as an admirable digest of the numberless observations made with regard to the development of animals during the quarter of a century preceding its publication, and as a work of original research.

Balfour's reputation was now such that other universities became anxious to secure his services, and he was invited to succeed Professor George Rolleston at Oxford and Sir Wyville Thomson at Edinburgh.

Balfour and the guide Johann Petrus were killed, probably on 19 July 1882, attempting the ascent of the Aiguille Blanche, Mont Blanc, at that time unscaled.