i hate to say it, but i know all about salt rising bread.
1-- joy of cooking has a recipe for it.--at least the older editions did --

2-- as a science project in 8 grade, my son made salt rising bread.. it was a good demonstration of finding help full bacteria, by creating an environment that eleminated harmful bacteria..

3-- it is, to say the least, an aromatic process! but the bread taste good.

i used to bake all my own bread, so my kitchen has yeast spores about. i don't know if you'd be able for find yeast spores handy if there wasn't bread baking done on a regular basis.. but i could be wrong. most grapes have a "haze" on them, it is actually a varity of yeast that grows on the surface, making the fermenting of grapes rather easy.. i don't know what the yeast lives on when its not making bread.