Class 'MongoClient' not found

<code>[Jack:~ $] sudo pecl install mongo
pecl/mongo is already installed and is the same as the released version 1.6.14

[Jack:~ $] vi /etc/php.ini
extension=mongo.so

[Jack:~ $] apachectl restart
</code>

<code><?php error_reporting(E_ALL);
ini_set('display_errors', 1);
$mongo = new MongoClient();
</code></code>

<code>Fatal error: Class 'MongoClient' not found in /private/var/www/index.php on line 5</code>

<code>[Jack:~ $] sudo pecl install mongo
pecl/mongo is already installed and is the same as the released version 1.6.14

[Jack:~ $] vi /etc/php.ini
extension=mongo.so

[Jack:~ $] apachectl restart
</code>

<code><?php error_reporting(E_ALL);
ini_set('display_errors', 1);
$mongo = new MongoClient();
</code></code>

<code>Fatal error: Class 'MongoClient' not found in /private/var/www/index.php on line 5</code>