Was Paul Morphy a slow player? In Milan Vidmar's book Goldene Schachzeiten he writes that the brilliant Paul Morphy was known to be an extraordinarily slow player, who would probably have had a hard life if time control were part of the chess battle.

I was shocked to read this because earlier I had always read that Morphy was an exceptionally fast player. Can anyone explain this controversy with access to reliable sources?
My item here does not "explain the controversy", but for a contemporary tournament comment concerning Morphy, see top of page 90 here: https://archive.org/details/bookoffirstameri00fisk

From the First American Chess Congress book, quoting an article in The Chess Monthly:


  Mr. Morphy is rapid in his moves and quick in his combinations, his
  time on any move never having reached a quarter of an hour; Mr.
  Paulsen is exceedingly slow, some of his moves having occupied more
  than an hour and several in succession having exceeded thirty minutes.


On page 246 and 248, specific listings of moves longer than 5 minutes for two of the Morphy-Paulsen games are given, and a similar comment on page 255.