Abstract Eysenck has summarized the history of the Galen theory of personality types and, while changing the theory from a categorical to a dimensional model, has suggested that it might be operationalized in terms of his factors of Extraversion and Neuroticism. The descriptors that Eysenck provides (and which are commonplace in everyday language) include not only traits, but states as well. This led us to predict that these personality types should evince different patterns and ranges of moods (states) and thus necessitates a crucial test of this ancient typology, specifically in the operationalized form suggested by Eysenck. In a preliminary test of this, Howarth (1988a) demonstrated that expected mood differences among the four types—Melancholic, Sanguine, Phlegmatic, and Choleric—did indeed emerge, suggesting the need for the formulation of the more crucial test over time. In order to test this possibility, 39 representatives of the four groups were selected from a total of 467 persons who had taken the Eysenck Personality Questionnaire. They then completed the Howarth Mood-Adjective Checklist (HMACL) over a 10-day period. Their responses were anlyzed using multiple discriminant functions and it was shown that the four types were clearly discriminable in a meaningful manner. Thus, our empirical investigation supports this classical theory of personality as herein defined both on the trait and on the state side.