[Gpdd] MISC. - 2 queries

[ROYCE LARSON]

     I've only been involved with the GPDD for a month or so now but have gotten a lot of helpful info and have written in several times. I have two questions that maybe some other newcomers share:
  1.. I have obviously deduced what the Rainbow Bridge is but where did this reference come from? 
  2.. I have also seen DSN referred to (as a helpline for guinea pig troubles?). Is this correct and can someone tell what it is exactly and how to use it?
Thanks so much.

Carl and Bud