Love Potion

The philtrum (Latin philtrum, Greek philtron, 'love potion'), is a medial cleft common to many mammals, extending from the nose to the upper lip, and, together with a glandular rhinarium and slit-like nostrils, is believed to constitute the primitive condition for mammals in general.  For humans and most primates, the philtrum survives only as a vestigial medial depression between the nose and upper lip.  The human philtrum, bordered by ridges, is also known as the infranasal depression, but has no apparent function.