I was in the company of our own Calvisius Taurus at Athens when I read this, and I asked how much sense he thought it made. He said: "As an account of what happens when the blood is diffused or concentrated, it is accurate and true. But he has not said why these things happen. The question of cause is still open: why does fear concentrate the blood, and shame scatter it? After all, shame is a sub-category of fear, as the philosophers define it: 'Shame is the fear of deserved blame.' "
Aulus Gellius, Attic Nights 19.6