When Capt. Lukas is first seen in the casino, his hair, eyebrows, mustache are all black, with a little gray at the temples. The next day on, the ship, all of his hair is gray.
Moritz refers to the uterus of the arctic worm. Only mammals have uteri.
When Elsa Lübing reads from the Book of Revelation, her Bible is open about 200 pages from the end.
When Smilla's father shows her the X-rays of the worms in the heart, he points out what remains of the liver and lower esophagus, then says "This is the heart, what's left of it". He's actually pointing to an upside-down X-ray of the upper abdomen. The "heart" is actually bowel gas in the intestine.
On the boat while, listening to the tape, Licht tells Smilla that an EEG is monitoring someone's heart. EEGs measure brain waves; EKGs (also called ECGs) measure heart rate and electrical activity.