Protected variable vs protected function

Hi,

When extending a class, I can override a protected function of the base class, and other functions of the base class will then use the function from my derived class.

class TestSlave extends TestMaster {
    protected function printInternal() {
        System.println( "Slave" );
    }
    public function initialize() {
        TestMaster.initialize();
    }
}

class TestMaster {
    protected function printInternal() {
        System.println( "Master" );
    }
    public function print() {
        printInternal();
    }
}

However this seems to work only for functions. For member variables, I have to declare them public for this to work, like in the example below. If I'd declare _text as protected in this example, the compiler will tell me "Attempting to override protected variable from a parent class.".

class TestSlave extends TestMaster {
    var _text = "Slave";
    public function initialize() {
        TestMaster.initialize();
    }
}

class TestMaster {
    var _text = "Master";
    public function print() {
        System.println( _text );
    }
}

Is there any sense behind this difference between functions and variables? Can I achieve this for a variable without making it public?