A marrow bone of a corpse or a marrow bone of sacrificial animals: [if] one touches them either closed or punctured, he is tamei. A marrow bone of a neveilah or a marrow bone of a sheretz: [if] one touches them when they are closed, he is tahor; [if] they are punctured at all, they convey tumah through contact. How do we know that the same applies to carrying? Because Scripture states (Leviticus 11:39-40): He who touches . . . and he who carries . . . — whatever comes within the scope of [tumah through] contact comes within the scope of [tumah through] carrying; whatever does not come within the scope of [tumah through] contact does not come within the scope of [tumah through] carrying.

The egg of a sheretz in which an embryo has been formed is tahor; [if] it has been punctured even slightly, it is tamei. A mouse that is half flesh and half earth: [If] one touches the flesh, he is tamei; [if he touches] the earth, he is tahor. R’ Yehudah says: Even [if] he touches the earth opposite the flesh, he is tamei.