The oldest and st method, then, of describing differences in personality was to (36) people according to (37) . Such a system is called a Typology. A famous example of this method was (38) forth in Greece about the year 400B. C. A (39) named Hippocrates theorized that there were four (40) , or humors, in the body: blood, (41) bile (胆汁), black bile, and phlegm (粘液). (42) to each humor, there (43) a definite type of personality. A person in whom all four humors were in perfect balance had a harmonious personality. (44) Someone with too much yellow bile was irritable and easily angered. (45) . An oversupply of phlegm caused a human being to he slow and unfeeling. Other features of people, such as their faces and figures, have also been used to classify personality. (46) .