The next sentences following your quote are also hilarious: > ...then, I account it high time to get to sea as soon as I can. This is my substitute for pistol

The next sentences following your quote are also hilarious: > ...then, I account it high time to get to sea as soon as I can. This is my substitute for pistol and ball. With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship. The humor gives Ishmael an everyman quality. Unlike Cato's grand "philosophical flourish", Ishmael "quietly" takes to the sea. Simultaneously, Ishmael has the mind of a poet, such as when he refers to taking to sea as his response to wanting to shoot himself or someone with "pistol and ball." Melville is basically saying that men, like Ishmael, go to sea so they won't go postal.