The short answer is the neutral and ground are normally connected in exactly one place: at the main disconnect, which is usually close to the meter. Most main panels have a screw or jumper so you can easily tie the ground and neutral together. What you don't want to do is to create a ground loop, where ground and neutral are connected together at multiple places some distance apart. So if you're adding a subpanel to an existing main panel, don't bond the ground and neutral, but confirm they're properly grounded at the main.
As for what they did in the fifties, that was before my time. Ole John T can probably answer, I think he passed his PE back in '53.
General rule of thumb: never assume existing house wiring was done correctly. When in doubt, check with the code or a licensed electrician.