• General entities are a somewhat arcane way of "including text".

• Similar things can now be accomplished by use of the XInclude last-call draft[1].

• But if you insist, you can declare them:

  <!ENTITY mystuff "Here's some replacement text">

  and then use it:

  <p>After this I'll get my text: &mystuff;</p>

  but it requires putting the declaration into the "internal subset of the document type declaration"--which we aren't going to dig too deep into.

[1] http://www.w3.org/TR/xinclude/