diff --git a/src/reagent/ratom.cljs b/src/reagent/ratom.cljs
index 51cb189..8f50bb8 100644
--- a/src/reagent/ratom.cljs
+++ b/src/reagent/ratom.cljs
@@ -325,14 +325,12 @@
 ;;;; reaction
 
 (defprotocol IDisposable
-  (dispose! [this]))
+  (dispose! [this])
+  (add-on-dispose! [this f]))
 
 (defprotocol IRunnable
   (run [this]))
 
-(defprotocol IReaction
-  (add-on-dispose! [this f]))
-
 (defn- handle-reaction-change [this sender old new]
   (._handle-change this sender old new))
 
@@ -455,13 +453,6 @@
             (._run this false)))))
     state)
 
-  IReaction
-  (add-on-dispose! [this f]
-    ;; f is called without arguments when Reaction is no longer active
-    (if-some [a (.-on-dispose-arr this)]
-      (.push a f)
-      (set! (.-on-dispose-arr this) (array f))))
-
   IDisposable
   (dispose! [this]
     (let [s state
@@ -476,7 +467,13 @@
         (.on-dispose this s))
       (when-some [a (.-on-dispose-arr this)]
         (dotimes [i (alength a)]
-          ((aget a i))))))
+          ((aget a i) this)))))
+
+  (add-on-dispose! [this f]
+    ;; f is called with the reaction as argument when it is no longer active
+    (if-some [a (.-on-dispose-arr this)]
+      (.push a f)
+      (set! (.-on-dispose-arr this) (array f))))
 
   IEquiv
   (-equiv [o other] (identical? o other))
diff --git a/test/reagenttest/testratom.cljs b/test/reagenttest/testratom.cljs
index fec6b84..bf83036 100644
--- a/test/reagenttest/testratom.cljs
+++ b/test/reagenttest/testratom.cljs
@@ -248,7 +248,9 @@
           res (rv/atom nil)
           cns (rv/make-reaction #(reset! res @c)
                                 :auto-run true)]
-      (rv/add-on-dispose! b #(reset! disposed true))
+      (rv/add-on-dispose! b (fn [r]
+                              (is (= r b))
+                              (reset! disposed true)))
       (rv/add-on-dispose! c #(reset! disposed-c true))
       (rv/add-on-dispose! cns #(reset! disposed-cns true))
       @cns