I would like to know if is possible to inquiry variable values using older blocks.

For example I have

```
contract Simple {
    string32 message public;

    function Simple() {
        message = msg.sender;
    }
}

```

Is it possible to retrieve the value of the message 1 month ago? Is there a method that let me inspect such variable on particular blockheight?

Is there a method that retrieves all different values that are found on the blockchain?

Thank you very much.