There is a theme of the seaman's notion of luck and the curiosity of the scientists. Dr Amos Jacob brings aboard a preserved hand exhibiting what is described as palmar aponeurosis - and now known as Dupuytren's contracture, named for distinguished surgeon and Maturin's friend Baron Guillaume Dupuytren, a hand with the fingers bent inwards and the fingernails growing through the flesh of the palm. It is stored in the alcoholic spirits of wine to preserve it. Stephen Maturin also brings aboard a narwhal tusk given him by Aubrey from a previous Baltic voyage.