Yosef Karo, Shulchan Aruch — 42: Laws of Treifot of the gall bladder
“ If the gall bladder is Nirsakh to a different place, it's kosher (Mordekhai p"at and A"V long v.) . (And see below Siman 46) . 2 If it was removed by action or it's missing, it's treif.3 If the gall bladder is missing, he tears the liver in a crosshatch pattern and tastes it with his tongue. If he tastes bitterness it's kosher, but if he doesn't taste bitterness, he roasts it on embers and tastes it and if it contains a bitter taste it's kosher, and if not it's treif. ”
