 He published works of Paracelsus and various Paracelsians but also served as the chief printer of Paracelsus's leading critic Thomas Erastus.In 1570 Perna sent the artist Tobias Stimmer to Como to copy the famous collection of historical portraits in the Giovio Collection.Stimmer's distinctive woodcuts decorate numerous editions of Paolo Giovio, brought out by Perna and Heinrich Petri.