According to Galen , these elements were used by Hippocrates in describing the human body with an association with the four humours : yellow bile ( fire ) , black bile ( earth ) , blood ( air ) , and phlegm ( water ) .
Galen said these elements were used by Hippocrates to describe the human body . The elements are linked to the four humours : phlegm ( water ) , yellow bile ( fire ) , black bile ( earth ) , and blood ( air ) . )