[Veterinary hematoscopy in late antiquity]

The classical humoral theory was no unfounded abstraction. On the contrary, it was based on phenomena which led to the recognition of the nature of the most important of the four humors: the blood of sick people differed from that of healthy persons. Examples from the works of the Greek and Roman veterinarians of the period from the 3rd to the 5th centuries A.D. are given, that hematoscopy was also performed by veterinarians. Bloodletting was not only a routinely applied preventive measure or a panacea, but also a prerequisite for hematoscopy, and thus a part of diagnostic.