Umbilical cord still attached at 6 weeks?

My baby had his cord still attached after one week and the Dr. put this silver stuff around it to help it fall off. I thinks she said it was called silver nitrate. It was bright silver and looked like metal and supposedly it help the tissue to heal quicker and the cord to fall off. 3 days later it was completely gone. Call her Dr. a.s.a.p and ask for silver nitrate. They'll know what you're talking about. You can also do an internet search to get some more info on it. The best thing to do is leave it and have the Dr apply that substance and allow it to fall of naturally. It won't be long. Oh yea...they told me not to use alcohol for any reason and that after the silver nitrate it would fall off. They said to just clean it with water until then.