When anyone attains to over a century at the time of their death it is inevitable that there should be few, even of near contemporaries, who can attest to the personal qualities that marked the individual in the full vigour of his career, but this deficiency is less marked with respect to H. N. Ridley, since he retained so much of his vigour and particularly his mental zest until almost the closing years of his life and, moreover, he fortunately left a personal record that has been invaluable in reconstructing the beginnings of his career. The writer is also indebted to his widow and to Mr I. H. Burkill, who succeeded Ridley as Director of the Botanic Gardens, Straits Settlements, from 1912 to 1925, for help in relation to the earlier years. Henry Nicholas Ridley was born on 10 December 1855 at the period when plant physiology under the influence of Dutrochet, Leibig and Boussingault was beginning to affect the general approach to the study of plants, and when Hofmeister had conclusively shown the nature of the sexual process in phanerogams and had given an impetus to the study of the life history of plants. Thus Ridley grew up in a period of great intellectual activity but, above all, in its influence on the young men—the
Origin of Species
appeared when he was four years old. By the time Ridley was a student this had become a vitalizing influence in botanical thought and outlook, which gave a new significance to the study of modes of dispersal of seeds and fruits and to the geographical distribution of plants, that had a lifelong effect on Ridley’s concepts and interests.