diff --git a/Cantera/src/transport/TransportBase.h b/Cantera/src/transport/TransportBase.h
index 31feb3247..489ada4c6 100755
--- a/Cantera/src/transport/TransportBase.h
+++ b/Cantera/src/transport/TransportBase.h
@@ -153,6 +153,9 @@ namespace Cantera {
             const doublereal* state2, doublereal delta, 
             doublereal* fluxes) { err("getMolarFluxes"); }
 
+        virtual void getMassFluxes(const doublereal* state1,
+            const doublereal* state2, doublereal delta, 
+            doublereal* fluxes) { err("getMassFluxes"); }
 
         /**
          * Thermal diffusion coefficients [kg/m/sec].