On the manual page:
http://www.php.net/manual/en/language.oop.constructor.php

The following code lacks an "echo" in function C (shown in square brackets).
-------
class A {
  function A() {
    echo "I am the constructor of A.<br>\n";
  }
}
class B extends A {
  function C() {
    [should have echo here?] "I am a regular function.<br>\n";
  }
}
// no constructor is being called in PHP 3.
$b = new B;