diff --git a/lib/delphi/src/Thrift.Protocol.pas b/lib/delphi/src/Thrift.Protocol.pas
index 36509ca..609dfc6 100644
--- a/lib/delphi/src/Thrift.Protocol.pas
+++ b/lib/delphi/src/Thrift.Protocol.pas
@@ -29,6 +29,7 @@
   Contnrs,
   Thrift.Exception,
   Thrift.Stream,
+  Thrift.Utils,
   Thrift.Collections,
   Thrift.Transport;
 
@@ -111,12 +112,6 @@
     function GetProtocol( const trans: ITransport): IProtocol;
   end;
 
-  TThriftStringBuilder = class( TStringBuilder)
-  public
-    function Append(const Value: TBytes): TStringBuilder; overload;
-    function Append(const Value: IThriftContainer): TStringBuilder; overload;
-  end;
-
   TProtocolException = class( TException)
   public
     const // TODO(jensg): change into enum
@@ -292,9 +287,8 @@
     constructor Create( trans: ITransport );
   end;
 
-  IBase = interface
-    ['{08D9BAA8-5EAA-410F-B50B-AC2E6E5E4155}']
-    function ToString: string;
+  IBase = interface( ISupportsToString)
+    ['{AFF6CECA-5200-4540-950E-9B89E0C1C00C}']
     procedure Read( const iprot: IProtocol);
     procedure Write( const iprot: IProtocol);
   end;
@@ -1034,19 +1028,6 @@
   inherited HiddenCreate(Msg);
 end;
 
-{ TThriftStringBuilder }
-
-function TThriftStringBuilder.Append(const Value: TBytes): TStringBuilder;
-begin
-  Result := Append( string( RawByteString(Value)) );
-end;
-
-function TThriftStringBuilder.Append(
-  const Value: IThriftContainer): TStringBuilder;
-begin
-  Result := Append( Value.ToString );
-end;
-
 { TBinaryProtocolImpl.TFactory }
 
 constructor TBinaryProtocolImpl.TFactory.Create(AStrictRead, AStrictWrite: Boolean);