diff --git a/library/HTMLPurifier/Token.php b/library/HTMLPurifier/Token.php
index cfd4bd7e..b1ff93c3 100644
--- a/library/HTMLPurifier/Token.php
+++ b/library/HTMLPurifier/Token.php
@@ -3,7 +3,7 @@
 /**
  * Abstract base token class that all others inherit from.
  */
-class HTMLPurifier_Token
+abstract class HTMLPurifier_Token
 {
     /**
      * Line number node was on in source document. Null if unknown.
diff --git a/library/HTMLPurifier/Token/Tag.php b/library/HTMLPurifier/Token/Tag.php
index c30b50cb..f65235a9 100644
--- a/library/HTMLPurifier/Token/Tag.php
+++ b/library/HTMLPurifier/Token/Tag.php
@@ -3,7 +3,7 @@
 /**
  * Abstract class of a tag token (start, end or empty), and its behavior.
  */
-class HTMLPurifier_Token_Tag extends HTMLPurifier_Token
+abstract class HTMLPurifier_Token_Tag extends HTMLPurifier_Token
 {
     /**
      * Static bool marker that indicates the class is a tag.