More on Sick as a Dog from Infoplease:

• Sick as a Dog - Sick as a Dog (See Similes.) Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894 Related ...
• Identification Marks: None (Rysopis) - Starring Jerzy Skolimowski, Elzbieta Czyzewska, Tadeusz Minc, Andrzej Zarnecki, Jacek Szczek
• Dog-sick - Dog-sick Sick as a dog. We also say “Sick as a cat.” The Bible speaks of dogs ...
• Dictionary of Phrase and Fable: D - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "D"
• Dictionary of Phrase and Fable: S - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "S"