Find Incremental Dialog Box

  The Find Incremental dialog box lets you search an
  ASCII text message for the text you specify.  The search
  is performed as you enter each character.

  In the Pattern entry box, type the text you want to search
  for.  If you want to find only exact matches of text, including
  upper and lower case letters, click on the Case Sensitive
  Searches option.

  Mail will start at the beginning of the message and search
  forward.

  Click on the Next button to search forward through the
  message for the next occurrence of the text, or click on
  the Previous button to search backwards for the previous
  occurrence.  Click on the Cancel button to cancel the search.