diff --git a/Cantera/src/thermo/ThermoPhase.h b/Cantera/src/thermo/ThermoPhase.h
index 3d5ddb577..b1f844c51 100644
--- a/Cantera/src/thermo/ThermoPhase.h
+++ b/Cantera/src/thermo/ThermoPhase.h
@@ -1,3 +1,5 @@
+//HI
+
 /**
  *  @file ThermoPhase.h
  * Header file for class ThermoPhase, the base class for phases with