Di Salas

“The relations between us in those latter days were peculiar. He was a man of habits, narrow and concentrated habits, and I had become one of them. As an institution I was like the violin, the shag tobacco, the old black pipe, the index books, and others perhaps less excusable. When it was a case of active work and a comrade was needed upon whose nerve he could place some reliance, my role was obvious. But apart from this I had uses. I was a whetstone for his mind. I stimulated him. He liked to think aloud in my presence. His remarks could hardly be said to be made to me--many of them would have been as appropriately addressed to his bedstead--but none the less, having formed the habit, it had become in some way helpful that I should register and interject. If I irritated him by a certain methodical slowness in my mentality, that irritation served only to make his own flame-like intuitions and impressions flash up the more vividly and swiftly. Such was my humble role in our alliance.”
― Arthur Conan Doyle, Adventure of the Creeping Man