On this stamp the symbol for medicine is incorrect. The "proper" medical symbol is the staff of Aesculapius (or Aesclepios in Greek) with a single serpent entwined around a cypress branch, not the caducceus of Hermes which is two entwined serpents around Hermes' staff.

     This error and its counterpart, the use of the staff of Aesculapius for the caducceus of Hermes is often made on stamps.