Hullin 121: Check the Knife!

More on items that join with meat to achieve a volume of food that would lead to the imparting of impurity. Including "allal" - which this daf defines (nuchal ligaments?). With a focus on what aspects can join with meat. Also, if a Jew slaughters a non-kosher animal for a non-Jew's consumption (or the converse) -- the implications of that case, as to when impurity would be imparted, or when there would be halakhic complications to begin with.