diff --git a/lib/bip32.js b/lib/bip32.js
index 3264e76..a7f03a6 100644
--- a/lib/bip32.js
+++ b/lib/bip32.js
@@ -8,9 +8,13 @@ var Random = require('./random');
 var bn = require('./bn');
 var constants = require('./constants');
 
-var BIP32 = function BIP32() {
+var BIP32 = function BIP32(obj) {
   if (!(this instanceof BIP32))
-    return new BIP32();
+    return new BIP32(obj);
+  if (typeof obj === 'string') {
+    var str = obj;
+    this.fromString(str);
+  }
 }
 
 BIP32.prototype.fromRandom = function(networkstr) {
diff --git a/test/bip32.js b/test/bip32.js
index 96f0d33..72e4fa9 100644
--- a/test/bip32.js
+++ b/test/bip32.js
@@ -32,14 +32,14 @@ describe('BIP32', function() {
   var vector2_m02147483647h12147483646h2_public = 'xpub6FnCn6nSzZAw5Tw7cgR9bi15UV96gLZhjDstkXXxvCLsUXBGXPdSnLFbdpq8p9HmGsApME5hQTZ3emM2rnY5agb9rXpVGyy3bdW6EEgAtqt';
   var vector2_m02147483647h12147483646h2_private = 'xprvA2nrNbFZABcdryreWet9Ea4LvTJcGsqrMzxHx98MMrotbir7yrKCEXw7nadnHM8Dq38EGfSh6dqA9QWTyefMLEcBYJUuekgW4BYPJcr9E7j';
 
-
-  it('should initialize the class', function() {
-    should.exist(BIP32);
-  });
-
-  it('should create a bip32', function() {
-    var bip32 = new BIP32();
+  it('should make a new a bip32', function() {
+    var bip32;
+    bip32 = new BIP32();
+    should.exist(bip32);
+    bip32 = BIP32();
     should.exist(bip32);
+    new BIP32(vector1_m_private).toString().should.equal(vector1_m_private);
+    BIP32(vector1_m_private).toString().should.equal(vector1_m_private);
   });
 
   it('should initialize test vector 1 from the extended public key', function() {
@@ -266,6 +266,21 @@ describe('BIP32', function() {
     child2.extendedPublicKeyString().should.equal(vector2_m02147483647h12147483646h2_public);
   });
 
+  describe('testnet', function() {
+    it('should initialize a new BIP32 correctly from a random BIP32', function() {
+      var b1 = new BIP32();
+      b1.fromRandom('testnet');
+      var b2 = new BIP32().fromString(b1.extendedPublicKeyString());
+      b2.extendedPublicKeyString().should.equal(b1.extendedPublicKeyString());
+    });
+
+    it('should generate valid ext pub key for testnet', function() {
+      var b = new BIP32();
+      b.fromRandom('testnet');
+      b.extendedPublicKeyString().substring(0,4).should.equal('tpub');
+    });
+  });
+
   describe('#seed', function() {
 
     it('should initialize a new BIP32 correctly from test vector 1 seed', function() {
@@ -285,21 +300,6 @@ describe('BIP32', function() {
     });
   });
 
-  describe('testnet', function() {
-    it('should initialize a new BIP32 correctly from a random BIP32', function() {
-      var b1 = new BIP32();
-      b1.fromRandom('testnet');
-      var b2 = new BIP32().fromString(b1.extendedPublicKeyString());
-      b2.extendedPublicKeyString().should.equal(b1.extendedPublicKeyString());
-    });
-
-    it('should generate valid ext pub key for testnet', function() {
-      var b = new BIP32();
-      b.fromRandom('testnet');
-      b.extendedPublicKeyString().substring(0,4).should.equal('tpub');
-    });
-  });
-
   describe('#toString', function() {
     var bip32 = new BIP32();
     bip32.fromRandom('mainnet');