diff --git a/lib/BlockDb.js b/lib/BlockDb.js
index a64ae66..426f4c9 100644
--- a/lib/BlockDb.js
+++ b/lib/BlockDb.js
@@ -151,7 +151,7 @@ console.log('[BlockDb.js.137:data:]',data); //TODO
       });
   };
 
-  BlockDb.blockIndex = function(height, cb) {
+  BlockDb.prototype.blockIndex = function(height, cb) {
     var rpc  = new RpcClient(config.bitcoind);
     rpc.getBlockHash(height, function(err, bh){
       if (err) return cb(err);