The ninth perek of Massekhet Ḥullin begins on today’s daf. Entitled HaOr ve-HaRotev – “the skin and the meat juice,” this perek does not belong in Massekhet Ḥullin, based on its contents. In fact, the topics covered in this chapter actually relate to issues of tum’ah ve-tahara – ritual purity and defilement – and would be most appropriately discussed in one of the tractates in Seder Taharot. Nevertheless, it is included in Massekhet Ḥullin since the topics that appear here are practically related to issues that are clarified in this tractate, since activities such as ritual slaughter, removing the animal’s hide and cutting the animal apart all raise potential issues of ritual defilement.
All food items that become ritually defiled by contact with a dead body can potentially defile other food and drink (this is referred to as tum’at okhlin), but only if they are the size of an egg. The Mishna teaches that in the event that meat is not of sufficient size, it can be supplemented by other parts of the animal that are not ordinarily considered food. Thus, if the meat is the size of an egg if it is supplemented by the animal’s skin or congealed meat juice or bones, tendons, lower section of the horns or upper section of the hooves, then it will be susceptible to ritual defilement and it will defile other food or drink, as well.
A different type of ritual defilement discussed in the Mishna is tum’at neveila. A neveila is an animal that was killed by a predator or died on its own. Such an animal is ritually defiled and will defile others if it is minimally the size of an olive. In contrast with tum’at okhlin, the Mishna teaches that tum’at neveila requires that the meat be the size of an olive, and cannot be supplemented with the animal’s skin or congealed meat juice or bones, tendons, horns or hooves.