I much appreciate the honour of being allowed to supplement your more formal courses of study with regard to mental defectives by a few biographical particulars and personal reminiscences of one who may be designated as the pioneer in their training, and the earliest exponent of the educational principles essential to their mental development. I may add that the principles Séguin laid down some seventy years ago apply to a far wider range than the instruction of imbeciles, and I shall hope to show that his master mind anticipated many of the modern methods which of late years have been accepted by the educational world as recent discoveries. As Mr. Holman well puts it in the opening sentence of his admirable book (1) on Séguin (to which I would at once express my appreciative acknowledgments), “The world has not infrequently had to rediscover its great men after they were dead, though their works lived after them.” The voice of Séguin was indeed, in his own day, at any rate as far as general educational science was concerned, as of one crying in the wilderness, and was even derided by the self-satisfied educationalists of the time. His ideas were indeed in advance of the age in which he lived; but what joy would it have been to him to see a summer school of earnest students of the subject nearest to his heart!