Over the recent decades, we have seen an explosion in scientific knowledge, and medical technology has made it difficult for individuals to keep up with the current advancement. This explosion has established the need for sub specialization.
Historically, the practice of medicine went through historical phases. In Mesopotamia, there were two types of doctors: Asu, the scientific doctor, and Asipu, the temple healer. Both were treating people, dentists, and veterinarians.(1) Egyptian medicine was as advanced with some specialization.(2)