Hamlet Soliloquy Glossary: O, what a rogue and peasant slave am I! (2.2.555-612)
pigeon-liver'd and lack gall
Small pigeons are known as doves, and, in the Renaissance, the gentle disposition of the dove was explained by the argument that it had no gall and thus no capacity to feel resentment or to seek revenge. The liver also was seen as the body's storehouse for courage.