diff --git a/src/unpacked_node.h b/src/unpacked_node.h
index 044d76a3..34b6fd6a 100644
--- a/src/unpacked_node.h
+++ b/src/unpacked_node.h
@@ -39,7 +39,7 @@ namespace MEDDLY {
 #define ALLOW_SET_FROM_DDEDGE
 #define ALLOW_SET_FROM_POINTER
 
-// #define USE_STRUCT
+#define USE_STRUCT
 
 // ******************************************************************
 // *                                                                *