One of Sherlock Holmes’s defects – if, indeed, one may call it a defect – was that he was exceedingly loth to communicate his full plans to any other person until the instant of their fulfilment. Partly it came no doubt from his own masterful nature, which loved to dominate and surprise those who were around him. Partly also from his professional caution, which urged him never to take any chances. The result, however, was very trying for those who were acting as his agents and assistants.
The Hound of the Baskervilles
‘No, Watson; I fear that I could not undertake to recognize your footprint amid all the footprints of the world. If you seriously desire to deceive me you must change your tobacconist; for when I see the stub of a cigarette marked Bradley, Oxford Street, I know that my friend Watson is in the neighbourhood.'
Death on the Moor
The more outre and grotesque an incident is the more carefully it deserves to be examined, and the very point which appears to complicate a case is, when duly considered and scientifically handled, the one which is most likely to elucidate it.