diff --git a/Source/NSGCString.m b/Source/NSGCString.m
index f3d98bc30..7f3bef8b0 100644
--- a/Source/NSGCString.m
+++ b/Source/NSGCString.m
@@ -128,6 +128,20 @@
   return (unichar) _contents_chars[index];
 }
 
+- (NSString*) substringFromRange: (NSRange)aRange
+{
+  NSGMutableCString *s;
+
+  if (aRange.location > _count)
+    [NSException raise: NSRangeException format:@"Invalid location."];
+  if (aRange.length > (_count - aRange.location))
+    [NSException raise: NSRangeException format:@"Invalid location+length."];
+  s = [[NSGMutableCString alloc] initWithCapacity:aRange.length+1];
+  [s setCString:_contents_chars+aRange.location length:aRange.length];
+  [s autorelease];
+  return (NSString *)s;
+}
+
 // FOR IndexedCollection SUPPORT;
 
 - objectAtIndex: (unsigned)index