Class instantiation within another class?

Can anyone point out the problem with this logic: include class#1 include class#2 $class1 = new class1; $class1->method(); And within class1's "method" call, it does a "$class2 = new class2" I've not been able to get this to work, and am wondering if there is a fundamental limitation to making use of one class from within another. Essentially, I don't think it is recognizing the 2nd class, and this shows up when i attempt to do a "class2->method()" call. (Says no such beast exists). If, on the other hand, I instantiate both classes first, and then pass class2 as a parameter to class1 in the constructor, I have no problem accessing class2's methods... I'd thought it was something perhaps with the "global" declaration, but haven't been able to figure out how to "global"ly declare the class itself, prior to instantiation. Any ideas? Thomas