How did Galen improve Hippocrates' theory of the 4 humors?

Galen built upon Hippocrates' theory of the four humors by incorporating his own observations and anatomical studies, emphasizing the role of the body's organs and their functions in relation to health. He introduced the concept of the "pneuma," or vital spirit, which connected the humors to the body's physiological processes. Additionally, Galen categorized the humors not only by their qualities (hot, cold, wet, dry) but also by their corresponding organs, thereby creating a more comprehensive understanding of how imbalances could affect health and disease. This integration of anatomy and physiology marked a significant advancement in medical theory.