“I am sorry to hear this,” said he. “I only know Mr. Holmes through some business dealings which we have had, but I have every respect for his talents and his character. He is an amateur of crime, as I am of disease. For him the villain, for me the microbe. There are my prisons,” he continued, pointing to a row of bottles and jars which stood upon a side table. “Among those gelatine cultivations some of the very worst offenders in the world are now doing time.”

“It was on account of your special knowledge that Mr. Holmes desired to see you. He has a high opinion of you and thought that you were the one man in London who could help him.”

The little man started, and the jaunty smoking-cap slid to the floor.

“Why?” he asked. “Why should Mr. Holmes think that I could help him in his trouble?”