"All that's old shall be new again."

Galen was physician to the Roman Emperor Marcus Aurelius. He remains most famous for his codification of Hippocrates's 'four humors' as personality traits (a concept later adopted by Adler in his 'Four Lifestyle Theory'). Galen's investigations were however, far more wide ranging.

He was the first to identify the brain-mind relation, the basic working structure of the eye and ear, as well as distinguishing differences between motor and sensory nerves (i.e., so-called affective  and effective impulses). Did you know? Galen is credited with investigating increased physiological activity amongst lovers.

The next time you are nearby your lover check to see whether your pulse races and pupils dilate!