Conversation so far:
When did the Silver Age of the Batman comics start?
The Silver Age of the Batman comics started as the series continued during the rise in popularity of mystery and romance comics
What was the first comic book that Joker was in during the silver age of Batman comics?
In 1951, Finger wrote an origin story for the Joker in Detective Comics #168
What was the Joker's appearance during the Silver Age era of Batman comics as introduced in the Joker's origin story?
The origin introduced the characteristic of the Joker's disfigurement the result of a fall into a chemical vat.

Question: What was something else new about the Joker that was introduced?
Self-contained rewrite: What was something else new about the Joker that was introduced besides his disfigurement being the result of a fall into a chemical vat?