Besides the teacher-apprentice system, medical knowledge handed down in the family was another important way to train practitioners. It usually occurred between father and son, or other relatives and kin. In such an educational system the father unselfishly passed his knowledge to his son or other family members. Since they lived together, the student was imperceptibly influenced by what he saw and heard. Consciously or unconsciously he got the knowledge of medicinal herbs and formulas, and how to receive patients, all of which contributed to his study.
Xu’s family was the most famous family of practitioners for generations in the Northern Dynasty （386—589）. In seven generations, 12 celebrated practitioners emerged from this family.
