“...while the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty.”

“Who knows, Watson? Woman's heart and mind are insoluble puzzles to the male.”

“Is he not the celebrated author of The Dynamics of an Asteroid, a book which ascends to such rarefied heights of pure mathematics that it is said that there was no man in the scientific press capable of criticizing it?”

“The weak man becomes strong when he has nothing, for then only can he feel the wild, mad thrill of despair.”

“By a man's finger-nails, by his coat-sleeve, by his boots, by his trouser-knees, by the callosities of his forefinger and thumb, by his expression, by his shirt-cuff — By each of these things a man's calling is plainly revealed. That all united should fail to enlighten the competent inquirer in any case is almost inconceivable. You know that a conjurer gets no credit when once he has explained his trick; and if I show you too much of my method of working, you will come to the conclusion that I am a very ordinary individual after all.”

“As a rule, the more bizarre a thing is the less mysterious it proves to be. It is your commonplace, featureless crimes which are really puzzling, just as a commonplace face is the most difficult to identify.”

“It is a question of cubic capacity," said he; "a man with so large a brain must have something in it.”