diff --git a/Doc/Devel/internals.html b/Doc/Devel/internals.html
index d24869d10..94a82519d 100644
--- a/Doc/Devel/internals.html
+++ b/Doc/Devel/internals.html
@@ -42,6 +42,7 @@
 <li><a name="i7" href="#7">7. Debugging SWIG</a>
 <ul>
 <li><a name="i7.1" href="#7.1">7.1 Debugging DOH Types The Hard Way</a>
+<li><a name="i7.2" href="#7.2">7.2 Debugging DOH memory allocation problems</a>
 </ul>
 </ul>
 
@@ -1179,6 +1180,34 @@ Either <br>
 
 </ul>
 
+<a name="7.2" href="#i7.2">
+<h3>7.2 Debugging DOH memory allocation problems</h3>
+</a>
+
+<p>
+The DOH objects are reference counted and use pools for memory allocation.
+The implementation is in <tt>memory.c</tt>. When there are memory corruption problems,
+various memory allocator tools are normally used to diagnose problems. These can be used
+on SWIG and can be very useful. However, they won't necessarily find use of stale DOH objects,
+that is, DOH objects
+that are used after they have been deleted. This is because the DOH memory allocator
+grabs a chunk of memory from the C memory allocator and manages the usage internally.
+Stale DOH object usage can be checked for by defining <tt>DOH_DEBUG_MEMORY_POOLS</tt> in 
+<tt>memory.c</tt>. If an attempt to use an object is made after the reference count is
+zero, an assertion is triggered instead of quietly re-using the stale object...
+</p>
+
+<blockquote>
+<pre>
+swig: DOH/memory.c:91: DohCheck: Assertion `!DOH_object_already_deleted' failed.
+</pre>
+</blockquote>
+
+<p>
+This can be memory intensive as previously used memory in the pool is not re-used so is
+only recommended for diagnosing memory corruption problems.
+</p>
+
 <hr>
 Copyright (C) 1999-2010 SWIG Development Team.
 
diff --git a/Source/DOH/memory.c b/Source/DOH/memory.c
index 5197c34d8..e366f88e7 100644
--- a/Source/DOH/memory.c
+++ b/Source/DOH/memory.c
@@ -21,9 +21,7 @@ char cvsroot_memory_c[] = "$Id$";
 #endif
 
 /* Checks stale DOH object use - will use a lot more memory as pool memory is not re-used. */
-/*
-#define DEBUG_MEMORY_POOLS
-*/
+#define DOH_DEBUG_MEMORY_POOLS
 
 static int PoolSize = DOH_POOL_SIZE;
 
@@ -87,10 +85,10 @@ int DohCheck(const DOH *ptr) {
   register char *cptr = (char *) ptr;
   while (p) {
     if ((cptr >= p->pbeg) && (cptr < p->pend)) {
-#ifdef DEBUG_MEMORY_POOLS
+#ifdef DOH_DEBUG_MEMORY_POOLS
       DohBase *b = (DohBase *) ptr;
-      int already_deleted = b->type == 0;
-      assert(!already_deleted);
+      int DOH_object_already_deleted = b->type == 0;
+      assert(!DOH_object_already_deleted);
 #endif
       return 1;
     }
@@ -121,7 +119,7 @@ DOH *DohObjMalloc(DohObjInfo *type, void *data) {
   DohBase *obj;
   if (!pools_initialized)
     InitPools();
-#ifndef DEBUG_MEMORY_POOLS
+#ifndef DOH_DEBUG_MEMORY_POOLS
   if (FreeList) {
     obj = FreeList;
     FreeList = (DohBase *) obj->data;
@@ -132,7 +130,7 @@ DOH *DohObjMalloc(DohObjInfo *type, void *data) {
     }
     obj = Pools->ptr + Pools->current;
     ++Pools->current;
-#ifndef DEBUG_MEMORY_POOLS
+#ifndef DOH_DEBUG_MEMORY_POOLS
   }
 #endif
   obj->type = type;