I have heard, Mr. Holmes, that you can see deeply into the manifold wickedness of the human heart.

Living, as I do, in an educated and scientific atmosphere, I could not have conceived that the first principles of zoology were so little known. Is it possible that you do not know the elementary fact in comparative anatomy, that the wing of a bird is really the forearm, while the wing of a bat consists of three elongated fingers with membranes between?

Circumstantial evidence is occasionally very convincing, as when you find a trout in the milk, to quote Thoreau's example.

I have already explained to you that what is out of the common is usually a guide rather than a hindrance.

For the one and only time I caught a glimpse of a great heart as well as of a great brain.

Data!data!data!" he cried impatiently. "I can't make bricks without clay.

One forms provisional theories and waits for time or fuller knowledge to explode them. A bad habit, Mr. Ferguson, but human nature is weak. Sherlock Holmes speaking with Dr. Watson.