The mocking song and his boastful appearance led to calling Dr. Eisenbart (Ironbeard) a quack. Unmeritedly his name became a symbol for rough cures with bad success. In fact he was an expert in his profession who was in advance of his time and had helped many sick people. His daring operations created a sensation among his contemporaries. He was a joyful roue, too, who cleverly knew to gain the favour of the crowd.
The mocking song could possibly be created by his colleagues with less success.
[A little bit more understandale, I think]

Haruo (ex Liland?) - dont ask Babelfish, ask me, or Wolfgang, or Susanne (skw). We spek dem German gooder.