For healthy skin, collagen is key: This naturally occurring protein keeps skin smooth and youthful, but our bodies produce less collagen as we get older. The result? Thinner skin, dryness, and more wrinkles.
Definition of BLACK BILE. : a humor of medieval physiology believed to be secreted by the kidneys or spleen and to cause melancholy. ADVERTISEMENT.1681. a humor of medieval physiology believed to be secreted by the kidneys or spleen and to cause melancholy. ADVERTISEMENT. 1681.
yellow bile, and black bile. According to a publication of the Harvard University Press, The Classical. Tradition, the four humours were believed to exist in cycles according to the seasons and. constellations, revealing the strong influence of astrology on the theory.