diff --git a/textile/core.py b/textile/core.py
index d97f827e..045d9c95 100644
--- a/textile/core.py
+++ b/textile/core.py
@@ -56,33 +56,6 @@ def _normalize_newlines(string):
     return out
 
 
-_glyph_defaults = {
-    'quote_single_open':  '‘',
-    'quote_single_close': '’',
-    'quote_double_open':  '“',
-    'quote_double_close': '”',
-    'apostrophe':         '’',
-    'prime':              '′',
-    'prime_double':       '″',
-    'ellipsis':           '…',
-    'ampersand':          '&',
-    'emdash':             '—',
-    'endash':             '–',
-    'dimension':          '×',
-    'trademark':          '™',
-    'registered':         '®',
-    'copyright':          '©',
-    'half':               '½',
-    'quarter':            '¼',
-    'threequarters':      '¾',
-    'degrees':            '°',
-    'plusminus':          '±',
-    'fn_ref_pattern':     '<sup%(atts)s>%(marker)s</sup>',
-    'fn_foot_pattern':    '<sup%(atts)s>%(marker)s</sup>',
-    'nl_ref_pattern':     '<sup%(atts)s>%(marker)s</sup>',
-}
-
-
 class Textile(object):
     halign_re_s = r'(?:\<(?!>)|(?<!<)\>|\<\>|\=|[()]+(?! ))'
     valign_re_s = r'[\-^~]'
@@ -121,6 +94,32 @@ class Textile(object):
 
     doctype_whitelist = ['xhtml', 'html5']
 
+    glyph_definitions = {
+        'quote_single_open':  '&#8216;',
+        'quote_single_close': '&#8217;',
+        'quote_double_open':  '&#8220;',
+        'quote_double_close': '&#8221;',
+        'apostrophe':         '&#8217;',
+        'prime':              '&#8242;',
+        'prime_double':       '&#8243;',
+        'ellipsis':           '&#8230;',
+        'ampersand':          '&amp;',
+        'emdash':             '&#8212;',
+        'endash':             '&#8211;',
+        'dimension':          '&#215;',
+        'trademark':          '&#8482;',
+        'registered':         '&#174;',
+        'copyright':          '&#169;',
+        'half':               '&#189;',
+        'quarter':            '&#188;',
+        'threequarters':      '&#190;',
+        'degrees':            '&#176;',
+        'plusminus':          '&#177;',
+        'fn_ref_pattern':     '<sup%(atts)s>%(marker)s</sup>',
+        'fn_foot_pattern':    '<sup%(atts)s>%(marker)s</sup>',
+        'nl_ref_pattern':     '<sup%(atts)s>%(marker)s</sup>',
+    }
+
     def __init__(self, restricted=False, lite=False, noimage=False,
                  auto_link=False, get_sizes=False, html_type='xhtml'):
         """Textile properties that are common to regular textile and
@@ -200,7 +199,7 @@ def __init__(self, restricted=False, lite=False, noimage=False,
         self.glyph_search_initial[4] = re.compile(r'(\S)"(?=\s|%s|$)' %
                 self.pnct_re_s, re.U)
 
-        self.glyph_replace = [x % _glyph_defaults for x in (
+        self.glyph_replace = [x % self.glyph_definitions for x in (
             r'\1%(apostrophe)s\2',                # apostrophe's
             r'\1%(apostrophe)s\2',                # back in '88
             r'\1%(quote_single_close)s',          # single closing
@@ -904,9 +903,9 @@ def fBlock(self, tag, atts, ext, cite, content):
 
     def formatFootnote(self, marker, atts='', anchor=True):
         if anchor:
-            pattern = _glyph_defaults['fn_foot_pattern']
+            pattern = self.glyph_definitions['fn_foot_pattern']
         else:
-            pattern = _glyph_defaults['fn_ref_pattern']
+            pattern = self.glyph_definitions['fn_ref_pattern']
         return pattern % {'atts': atts, 'marker': marker}
 
     def footnoteRef(self, text):
diff --git a/textile/tests/__init__.py b/textile/tests/__init__.py
index f3ba9858..a12056f8 100644
--- a/textile/tests/__init__.py
+++ b/textile/tests/__init__.py
@@ -590,3 +590,22 @@ def testHTML5(self):
         result = '\t<p>We use <abbr title="Cascading Style Sheets"><span class="caps">CSS</span></abbr>.</p>'
         expect = textile.textile(test, html_type="html5")
         eq_(result, expect)
+
+
+class SubclassingTests():
+    """Test Textile subclassing ability."""
+    def testChangeGlyphs(self):
+        class TextilePL(textile.Textile):
+            glyph_definitions = dict(textile.Textile.glyph_definitions,
+                quote_double_open = '&#8222;'
+            )
+
+        test = 'Test "quotes".'
+        expect = '\t<p>Test &#8222;quotes&#8221;'
+        result = TextilePL().parse(test)
+        eq_(expect, result)
+
+        # Base Textile is unchanged.
+        expect = '\t<p>Test &#8220;quotes&#8221;'
+        result = textile.textile(test)
+        eq_(expect, result)