ORIGINAL: BobCo19-65
If you know you only got one lung and nothing else (which is hard to know), I'd get on it right away. Your only chance on it is to have it bleed out. You WILL be tracking a long ways.
Liver, or lung/liver combo, minimum of five hours. And it should be farily close if not pushed.
If you have questions like these, I'd suggest getting the book "Tracking wounded deer" by John Trout. He is an expert in this stuff.
Excellent advise right there. I haven't had the opportunity to read said book but I want to. Perhaps after I do I will revise my recovery thread. Here's a link for that with some great replies.
http://www.huntingnet.com/forum/tm.aspx?m=1665984