diff --git a/scheme/opt/flatten.scm b/scheme/opt/flatten.scm
index d373c8e..40a8717 100644
--- a/scheme/opt/flatten.scm
+++ b/scheme/opt/flatten.scm
@@ -114,7 +114,7 @@
 (define (add-cells exp vars)
   (do ((vars vars (cdr vars))
        (cells '() (if (assigned? (car vars))
-		      (cons (make-cell (car vars)) cells)
+		      (cons (make-make-cell (car vars)) cells)
 		      cells)))
       ((null? vars)
        (if (null? cells)
@@ -272,7 +272,7 @@
 ;----------------
 ; Cell manipulation calls.
 
-(define (make-cell var)
+(define (make-make-cell var)
   (make-node operator/set!
 	     (list 'set!
 		   var