Alas! it is the last hurdle which often floors the rider, and Thomas too was doomed to find the final ordeal an insurmountable one. As he crossed the room some evil chance made him think of the gossip outside and of his allusion to the abstruse substance known as cacodyl. Once let a candidate's mind hit upon such an idea as this, and nothing will ever get it out of his thoughts. Tom felt his head buzz round, and he passed his hand over his forehead and through his curly yellow hair to steady himself. He felt a frenzied impulse as he sat down to inform the examiners that he knew very well what they were going to ask him, and that it was hopeless for him to attempt to answer it.
The leading professor was a ruddy-faced, benevolent old gentleman, with spectacles and a kindly manner. He made a few commonplace remarks to his colleagues with the good-natured intention of giving the confused-looking student before him time to compose himself. Then, turning blandly towards him, he said in the mildest of tones-"Have you ever rowed in a pond?"
Tom acknowledged that he had.
"Perhaps, on those occasions," the examiner continued, "you may have chanced to touch the mud at the bottom with your oar."
Tom agreed that it was possible.
"In that case you may have observed that a large bubble, or a succession of them has risen from the bottom to the surface. Now, of what gas was that bubble composed?"
The unhappy student, with the one idea always fermenting on his brain, felt that the worst had come upon him. Without a moment's hesitation or thought he expressed his conviction that the compound was cacodyl.
Never did two men look more surprised, and never did two generally grave savants laugh more heartily than did the two examiners when they realized what the candidate had answered. Their mirth speedily brought him back to his senses. He saw with a feeling of despair that it was marsh gas which they had expected--one of the simplest and commonest of chemical combinations. Alas! it was too late now. He knew full well that nothing could save him. With poor marks in botany and zoology, such an error in chemistry was irreparable. He did what was perhaps the best thing under the circumstances. Rising from his chair he made a respectful bow to the examiners, and walked straight out of the room--to the great astonishment of the janitor, who had never before witnessed such a breach of decorum. As the student closed the door behind him he looked back and saw that the other professors had left their respective tables and were listening to an account of the incident from one of the chemists--and a roar of laughter the moment afterwards showed that they appreciated the humour of it. His fellow-students gathered round Tom outside in the hope of sharing in the joke, but he pushed them angrily aside and strode through the midst of them and down the University steps. He knew that the story would spread fast enough without his assistance. His mind was busy too in shaping a certain resolution which he had often thought over during the last few months.