diff --git a/ordinary-differential-equations/ode-system.lisp b/ordinary-differential-equations/ode-system.lisp
index 2e0490fbb9f1716097773064524dfd90c1f63981..8426c9a7ad4eae6c0a1fe2755bab52662e86f76f 100644
--- a/ordinary-differential-equations/ode-system.lisp
+++ b/ordinary-differential-equations/ode-system.lisp
@@ -1,8 +1,8 @@
 ;; ODE system setup
 ;; Liam Healy, Sun Apr 15 2007 - 14:19
-;; Time-stamp: <2010-06-30 19:57:28EDT ode-system.lisp>
+;; Time-stamp: <2011-05-04 10:25:19EDT ode-system.lisp>
 ;;
-;; Copyright 2007, 2008, 2009 Liam M. Healy
+;; Copyright 2007, 2008, 2009, 2010, 2011 Liam M. Healy
 ;; Distributed under the terms of the GNU General Public License
 ;;
 ;; This program is free software: you can redistribute it and/or modify
@@ -27,9 +27,13 @@
 	       &key jacobian (scalarsp t) (stepper '+step-rk8pd+)
 	       (absolute-error 1.0d-6) (relative-error 0.0d0))
      &body body)
-  "Environment for integration of ordinary differential equations."
-  ;; Note: the case jacobian=nil is not properly handled yet; it
-  ;; should put a null pointer into the struct that is passed to GSL.
+  "Environment for integration of ordinary differential equations when dependent variables are individually named scalars."
+  ;; Note: If the dependent variables are in a foreign array, it is
+  ;; best to call the ODE functions directly; this macro is just
+  ;; provided as a convenience if they are separate scalars.
+  ;; Note:
+  ;; the case jacobian=nil is not properly handled yet; it should put
+  ;; a null pointer into the struct that is passed to GSL.
   (let ((dep (make-symbol "DEP"))
 	(ctime (make-symbol "CTIME"))
 	(cstep (make-symbol "CSTEP")))