On the Nature of Man is attributed to Polybus, the son in law and disciple of Hippocrates, through a testimony from Aristotle's History of Animals.
The content is based on observation and defended by logical explanations of the causes of each disease in order to readily meet outside criticism.
[3] On the Nature of Man shares the general Hippocratic interest in humorism and in such treatments as bloodletting.
"[4] On the Nature of Man gives first hand accounts and explanations of individual medical cases.
The lasting impact of On the Nature of Man was extremally significant in the field of medicine and was critical to all the teaching in Hippocratic Corpus.