Jonathan tells the captain that Max might have yellow fever and that if anyone finds out, the ship could be quarantined. But yellow fever is spread by mosquitoes, and isn't contagious between humans.
In this episode Jennifer plays a countess that grew up around Madrid. In the doctor's office, the captain speaks one word of Spanish that she appears to not understand, but when confronted in the Captain's office, she speaks a couple of sentences fluently.
President Theodore Roosevelt's picture is on the counterfeit plate. He's never been on any US bills.
Near the end of the episode, Jonathan and the captain are fighting near the ships railing, the captain goes overboard. He can clearly be heard, vowing revenge on Jonathan. After that much of a drop, he wouldn't be able to be heard clearly.