Patrick O'brian said this quote

“ Valuable and ingenious he might be, thought Jack, fixing him with his glass, but false he was too, and perjured. He had voluntarily sworn to have no truck with vampires, and here, attached to his bosom, spread over it and enfolded by one arm, was a greenish hairy thing, like a mat - a loathsome great vampire of the most poisonous kind, no doubt. ‘I should never have believed it of him: his sacred oath in the morning watch and now he stuffs the ship with vampires; and God knows what is in that bag. No doubt he was tempted, but surely he might blush for his fall?’No blush; nothing but a look of idiot delight as he came slowly up the side, hampered by his burden and comforting it in Portuguese as he came.‘I am happy to see that you were so successful, Dr Maturin,’ he said, looking down into the launch and the canoes, loaded with glowing heaps of oranges and shaddocks, red meat, iguanas, bananas, greenstuff. ‘But I am afraid no vampires can be allowed on board.’‘This is a sloth,’ said Stephen, smiling at him. ‘A three-toed sloth, the most affectionate, discriminating sloth you can imagine!’ The sloth turned its round head, fixed its eyes on Jack, uttered a despairing wail, and buried its face again in Stephen’s shoulder, tightening its grip to the strangling-point. ”