C++ :: Cannot Access Protected Members Of Parent Class

I am doing C++ data structures exercises, and I am still learning some of the more basic concepts. I have a parent class:

template<class T>
class linkedListType {
public:
protected:
int count;
nodeType<T> *first;
nodeType<T> *last;
private:
};

Derived class:

#include "linkedListType.h"
template<class T>
class orderedLinkedList: public linkedListType<T> {
public:
void mergeList(orderedLinkedList<T> &list1, orderedLinkedList<t> &list2) {
first = list1.first;
...
} private:
};

There is more code in my mergeList() function, but I included the line that is giving me problems. The error that my CodeBlocks compiler is giving me is that 'first' was not declared in this scope.

Strangely enough, if I change it to this->first, the error disappears.

1. Why does it not recognise 'first'?
2. Why would this->first work at all? Is the 'this' object a smart pointer?