Zevahim 22: Talmudic Science (again); Also, the Elders of the South

Liquid that can complete the volume of 40 se'ah of water needed for a mikveh also would work to fill the basin in the Temple. The question then is which substances meet this definition of the liquids that can indeed complete the water of a mikveh or the kiyor. Plus, a discussion of the insects that "develop from water" - and the quesiton of science in the Talmud. Also, with regard to impurity that invalidates the kohen for the service, must it come from a dead body? What about a creepy-crawlie? (or reverse the cases, for that matter) Plus, the distinction between those who bring about atonement as compared to those who achieve atonement.