Ideas about biology and the human body were very different in 1651 than they are in the twenty-first century. One important figure who shaped ideas of the time was Galen, who developed humoral theory (also known as humorism or Galenic theory). Many people (including medical practitioners) used this theory to explain a number of maladies and bodily functions, as well as differences between the sexes. Galen explained that, because of the different balances of the humors (blood, phlegm, black bile, and yellow bile), women were generally “colder and wetter” and men were generally “hotter and dryer." Also, medical experts following Galen believed that women’s bodies were the inverse of men’s. They “described the uterus as an inverted penis, and the ovaries as female testicles that remained inside the body because the female lacked sufficient heat to push them out."