diff --git a/websocket-sharp/Net/HttpUtility.cs b/websocket-sharp/Net/HttpUtility.cs
index 23e3b717..1356bf1f 100644
--- a/websocket-sharp/Net/HttpUtility.cs
+++ b/websocket-sharp/Net/HttpUtility.cs
@@ -459,12 +459,6 @@ namespace WebSocketSharp.Net
       _entities.Add ("euro", '\u20AC');
     }
 
-    private static bool isAlphabet (byte b)
-    {
-      return (b >= 65 && b <= 90)
-             || (b >= 97 && b <= 122);
-    }
-
     private static bool isAlphabet (char c)
     {
       return (c >= 'A' && c <= 'Z')