Deduce You Say (1956) ****

Daffy is Dorlock Homes, a famous detective "deducting" his taxes and trying to catch a dangerous killer. It's a great parody of Sir Conan Doyle's novels, with Porky Pig as "Watkins". Imaginative backgrounds, funny jokes and a memorable closing line ("Elementary, my dear Watkins, elementary", says Dorlock when asked in what school he's learned his craft).