My dear Sprigge,

Since it was you who first instructed me in the existence of the brain disease which forms the motif of this story, and furnished me with such illustrations of its working as enabled me to write the story, I am in honour bound to make the most public acknowledgment possible of this fact.

I therefore beg to inscribe your name on the title page of this volume in grateful recognition of an obligation which is not by any means discharged by such recognition. I am also moved to do so in remembrance of another kind of work in which I have been so fortunate as to have your invaluable collaboration.