cellio | daf bit: Temurah 7

(Today's daf is 8 but doesn't summarize well.)

This tractate begins with a discussion of exchanging animals that have been consecrated for other animals. This is forbidden by the torah but, if done anyway, takes effect, so there is discussion of the details. The mishna teaches: kohanim are allowed to exchange animals that belong to them and so are Israelites, but priests cannot exchange a sin-offering or guilt-offering. Why not? Because those offerings belong to the one who brings them until they are slaughtered, so before then they do not belong to the kohein and therefore he can't exchange them for different animals. So what about firstlings, which kohanim take possession of earlier (without slaughter)? This is complicated and controversial. (7b mishna, 8 g'mara on firstlings)

I'm having trouble following the argument on 8. Sorry.