[New materials on the history of veterinary medicine in Bulgaria]

Several tens of ritual plates are preserved in Bulgaria on which elements of glorification are found of god Mithras who gained popularity particularly in the 1st-IIIrd century in the regions of Thrace and today's North Bulgaria, then provinces of the Eastern Roman Empire. Mithras seemed to be respected by slaves, soldiers, and merchants alike, but was also an exemplar to the Roman emperors, being considered by them as Sol invictus or Deo invicto. The central scene in all plates is that of Mithras tauroctonus (Mithras, the killer of bulls). This scene is likewise of interest to veterinarians as it shows that in such early epoch the people that lived within the territory of Bulgaria of today used a method for the felling of large animals, the elements of which--fixing the head and bending it backwards, fastening the thorax with a belt or another loop, loading the animal's back--are still existing and are used in a number of modern methods of felling (that of Hess, the Caucasian way of felling, the Chinese one of Dou-Chan-Than, etc.) Besides, the people of ancient time knew that ruminants have an incomplete upper dentition. They skilfully employed this to bring animals that had to be felled into an unusual nonphysiologic posture. Not sooner than 16 centuries prior to the preformists (the spermists) they supported the concept that the testes were the source of life.