What Was The Role of David Herold

[RJNorton]

Regarding the little "prescription" package Powell held while talking to William Bell...has it ever been determined what really was in the package, if anything?

Also, regarding Mike Kauffman's explanation that Herold was sent by Powell to tell the others to delay the attacks...as far as I can tell, there can only be two sources that could possibly have this information: (1) a statement by Herold or (2) a statement by Powell. Is it possible Powell told Eckert this, and that is the source Mike Kauffman used?