ColdFusion & Polymorphism use

I have an animal object with a method call makeSound(). Then I have a feline object that extends animal with a method called makeSound(). Then I have an object named cat that extends feline with a method called makeSound(). If I instantiate the cat object and call it oCat, I can call oCat.makeSound() and get the cat sound. QUESTION IS, how do I call the makeSound() method in the feline object via the oCat handle? I am told it is possible but I have not been able to find out exactly how. I did read you need to pass a type reference to it but not sure what that means. Would it be oCat.makeSound(feline) ?? -------------- Dan O'Keefe