diff --git a/src/molecule.cpp b/src/molecule.cpp
index 36239352a3..8e772218c1 100644
--- a/src/molecule.cpp
+++ b/src/molecule.cpp
@@ -110,6 +110,7 @@ Molecule::Molecule(LAMMPS *lmp, int narg, char **arg, int &index) :
   // last molecule if have scanned all args
 
   if (iarg == narg) last = 1;
+  else last = 0;
 
   // initialize all fields to empty