For ten minutes or more he sat there motionless, hot tears boiling up from his eyes and falling silently between his fingers. Then at last he rose nervously from his seat, and reached down a volume from the shelf behind him. It was Prang's "Treatise on the Physiology of the Brain." He turned it over hurriedly for a few pages, till he came to the passage he was looking for. "Ah, I thought so," he said to himself, half aloud: "'Premonitory symptoms: facial distortions; infirmity of the will; inability to distinguish muscular movements.' Let's see what Prang has to say about it. 'A not uncommon concomitant of these early stages'--Great heavens, how calmly the man talks about losing your reason!-'is an unconscious or semi-conscious tendency to produce a series of extraordinary facial distortions. At times, the sufferer is not aware of the movements thus initiated; at other times they are quite voluntary, and are accompanied by bodily gestures of contempt or derision for passing strangers.' Why, that's what must have happened with that boy this morning! 'Symptoms of this character usually result from excessive activity of the brain, and are most frequent among mathematicians or scholars who have overworked their intellectual faculties. They may be regarded as the immediate precursors of acute dementia.' Acute dementia! Oh, Hetty! Oh, heavens! What have I done to deserve such a blow as this?" He laid his face between his hands once more, and sobbed like a broken-hearted child for a few minutes. Then he turned accidentally towards his tumbled manuscript. "No, no," he said to himself, reassuringly; "I can't be going mad. My brain was never clearer in my life. I couldn't have done a piece of good work like that, bristling with equations and figures and formulas, if my head was really giving way. I seemed to grasp the subject as I never grasped it in my life before. I never worked so well at Cambridge; this is a discovery, a genuine discovery. It's impossible that a man who was going mad could ever see anything so visibly and distinctly as I see that universal principle. Let's look again at what Prang has to say upon that subject." He turned over the volume a few pages further, and glanced lightly at the contents at the head of each chapter, till at last a few words in the title struck his eye, and he hurried on to the paragraph they indicated, with feverish eagerness. As he did so, these were the words which met his bewildered gaze.