diff --git a/modules/ripple_data/protocol/ripple_SerializedTypes.cpp b/modules/ripple_data/protocol/ripple_SerializedTypes.cpp
index 24771669f4..349c0242a2 100644
--- a/modules/ripple_data/protocol/ripple_SerializedTypes.cpp
+++ b/modules/ripple_data/protocol/ripple_SerializedTypes.cpp
@@ -466,7 +466,7 @@ bool STPathSet::isEquivalent (const SerializedType& t) const
     return v && (value == v->value);
 }
 
-bool STPath::hasSeen (const uint160& uAccountId, const uint160& uCurrencyID, const uint160& uIssuerID)
+bool STPath::hasSeen (const uint160& uAccountId, const uint160& uCurrencyID, const uint160& uIssuerID) const
 {
     for (int i = 0; i < mPath.size (); ++i)
     {
diff --git a/modules/ripple_data/protocol/ripple_SerializedTypes.h b/modules/ripple_data/protocol/ripple_SerializedTypes.h
index 2c01a4f47c..9ceb76bb1a 100644
--- a/modules/ripple_data/protocol/ripple_SerializedTypes.h
+++ b/modules/ripple_data/protocol/ripple_SerializedTypes.h
@@ -1241,7 +1241,7 @@ public:
     {
         mPath.clear ();
     }
-    bool hasSeen (const uint160& uAccountId, const uint160& uCurrencyID, const uint160& uIssuerID);
+    bool hasSeen (const uint160& uAccountId, const uint160& uCurrencyID, const uint160& uIssuerID) const;
     //  std::string getText() const;
     Json::Value getJson (int) const;