diff --git a/PhyObj/PhyObj.cc b/PhyObj/PhyObj.cc
index 9658a0b..e63f156 100644
--- a/PhyObj/PhyObj.cc
+++ b/PhyObj/PhyObj.cc
@@ -41,7 +41,7 @@ PhyObj::Geom::Geom(PhyObj::GeomType type, refptr< vector<float> > args)
 
 
 /********** PhyObj functions **********/
-void PhyObj::load(unsigned char *data, unsigned int size)
+void PhyObj::load(const unsigned char *data, unsigned int size)
 {
     string str((char *) data, size);
     stringstream istr(str, ios_base::in);
diff --git a/PhyObj/PhyObj.h b/PhyObj/PhyObj.h
index ee846c9..f735514 100644
--- a/PhyObj/PhyObj.h
+++ b/PhyObj/PhyObj.h
@@ -28,7 +28,7 @@ class PhyObj
         };
 
         /* Methods */
-        void load(unsigned char *data, unsigned int size);
+        void load(const unsigned char *data, unsigned int size);
         size_t getNumGeoms() { return m_geoms.size(); }
         refptr<Geom> getGeom(int i) { return m_geoms[i]; }