Nick's tie is tight when he's first seen with Flo, and then loose at the end the same scene.
A man running for his life from a lion has a big grin on his face.
At the end, when Nick (Humphrey Bogart) calls for Caesar to be sent into the ring, he calls to John Ridgely, "Tex, let him in!" But Ridgely's character is named Arch, not Tex.