# File lib/action_mailer/vendor/tmail-1.2.3/tmail/net.rb, line 106
    def mime_encode_text( body )
      self.body = NKF.nkf('-j -m0', body)
      self.set_content_type 'text', 'plain', {'charset' => 'iso-2022-jp'}
      self.encoding = '7bit'
    end