How can I call member variables of a class within a static method?

I am using some method to autoload helper files with functions. The only problem I am having now, is how to call the variables in that class.

Because I am not instantiating it as an object, $this won't work. But what will?

class some_helperclass {

var $some_variable  = '007';

public static function some_func()
    {
    //return 'all ok';
    if (self::some_variable !== FALSE)  
    {
       return  self::ip_adres;
    }
}

I can call the function from anywhere now with the help of spl_autoload_register().

some_helperclass:: some_func();