Cell Lysing Detergent

[Rick Bright]

I have a DNA extraction method that calls for Nonidet P-40 as the lysing
agent.  However, I cannot find a source in Fisher, Sigma, or Pharmacia. 
Does anyone have a source or catalog number for this detergent.

Also, is there a particular reason why one would use Nonidet P-40 over
SDS or Triton X-100 for lysing blood cells?  Are there particular
applications where one agent is better than others, or are do they serve
the purpose equally well for all applications?

I appreciate your assistance.

Rick Bright
rbright at mnw.net