--- groff-1.21/src/roff/troff/input.cpp	2010-12-31 08:33:08.000000000 +0100
+++ groff-1.21.period/src/roff/troff/input.cpp	2011-03-21 19:31:40.234710613 +0100
@@ -1932,6 +1932,10 @@
 	goto ESCAPE_HYPHEN;
       case '_':
 	goto ESCAPE_UNDERSCORE;
+      case '.':
+	type = TOKEN_SPECIAL;
+	nm = symbol("char46");
+	return;
       case '%':
 	goto ESCAPE_PERCENT;
       case ' ':