To a great mind, nothing is little.
Verified
designobservationperceptionawarenessdetailsSource: A Study in Scarlet, Arthur Conan Doyle, 1887
Spoken by Sherlock Holmes in 'A Study in Scarlet' (1887); the credit line in the corpus ('Sherlock Holmes, via Conan Doyle') correctly separates character from author. I am confident of the novel; I cannot pin the chapter from memory. Note that it is a fictional character's line, not Doyle speaking in his own voice.