Beaver extinction in part for the production of castoreum, which was used as an analgesic, anti-inflammatory, and antipyretic. Castoreum was described in the 1911 British Pharmaceutical Codex for use in dysmenorrhea and hysterical conditions (i.e. pertaining to the womb), for raising blood pressure and increasing cardiac output. The activity of castoreum has been credited to the accumulation of salicin from willow trees in the beaver's diet, which is transformed to salicylic acid and has an action very similar to aspirin. Castoreum continues to be used in perfume production. Castoreum can be used as an enhancer of vanilla, strawberry and raspberry flavorings.
Castor and Pollux a blow from his spear—but not before Castor called out to warn Pollux. In the ensuing brawl, Pollux killed Lynceus. As Idas was about to kill Pollux, Zeus, who had been watching from Mt. Olympus, hurled a thunderbolt, killing Idas and saving his son. Returning to the dying Castor, Pollux was given the choice by Zeus of spending all his time on Mount Olympus or giving half his immortality to his mortal brother. He opted for the latter, enabling the twins to alternate between Olympus and Hades. The brothers became the two brightest stars in the constellation Gemini ("the twins"):