Index: toltcl/pkgIndex.tcl
===================================================================
--- toltcl/pkgIndex.tcl	(revision 6d7c032b63bb775a1309be7a7c2053d3f174d7a2)
+++ toltcl/pkgIndex.tcl	(revision 981139106730e900a39e66a1fb0c15e72d3fbeda)
@@ -3,12 +3,18 @@
 proc LoadToltcl { version dir } {
   global tcl_platform
-  
-  set suffix [info sharedlibextension]
-  if {$tcl_platform(platform) eq "unix"} {
-    set name libtoltcl${version}[info sharedlibextension]
-  } else  {
-    set name toltcl.dll
+ 
+  set _version [ string map [ list "." "" ] $version ]
+  if {[info exist ::env(USE_TOLTCL_$_version)]} {
+    puts "requested to load Toltcl from $::env(USE_TOLTCL_$_version)"
+    load $::env(USE_TOLTCL_$_version)
+  } else {
+    set suffix [info sharedlibextension]
+    if {$tcl_platform(platform) eq "unix"} {
+      set name libtoltcl${version}[info sharedlibextension]
+    } else  {
+      set name toltcl.dll
+    }
+    load [file join $dir $name] Toltcl
   }
-  load [file join $dir $name] Toltcl
 }