The Valley of Fear Act 2, Scene 3 and 4

From the text:

“Dear me, Watson, is it possible that you have not penetrated the fact that the case hangs upon the missing dumb-bell? Well, well, you need not be downcast; for between ourselves I don’t think that either Inspector Mac or the excellent local practitioner has grasped the overwhelming importance of this incident. One dumb-bell, Watson! Consider an athlete with one dumb-bell! Picture to yourself the unilateral development, the imminent danger of a spinal curvature. Shocking, Watson, shocking!”

He sat with his mouth full of toast and his eyes sparkling with mischief, watching my intellectual entanglement. The mere sight of his excellent appetite was an assurance of success; for I had very clear recollections of days and nights without a thought of food, when his baffled mind had chafed before some problem while his thin, eager features became more attenuated with the asceticism of complete mental concentration. Finally he lit his pipe, and sitting in the inglenook of the old village inn he talked slowly and at random about his case, rather as one who thinks aloud than as one who makes a considered statement.

“A lie, Watson—a great, big, thumping, obtrusive, uncompromising lie—that’s what meets us on the threshold! There is our starting point. The whole story told by Barker is a lie. But Barker’s story is corroborated by Mrs. Douglas. Therefore she is lying also. They are both lying, and in a conspiracy. So now we have the clear problem. Why are they lying, and what is the truth which they are trying so hard to conceal? Let us try, Watson, you and I, if we can get behind the lie and reconstruct the truth.