The reddish version of the snow-white [nega appears] like wine mixed with snow. The reddish version of the lime-[colored nega] is like blood mixed with milk. These are the words of R’ Yishmael. R’ Akiva says: The red version of both of them is [the color of] wine mixed with water, except that [the red tinge] of snow is bright whereas that of lime is duller.

These four appearances combine with one an- other to make tahor, to confirm, or to confine: to confine that which remains the same at the end of the first week; to make tahor that which remains the same at the end of the second week; to confirm that which develops living skin or white hair, either initially, at the end of the first week, at the end of the second week, [or] after being declared tahor; to confirm that which develops an expansion [either] at the end of the first week, at the end of the second week, [or] after being declared tahor; to confirm someone who turns completely white after being declared tahor; to make tahor someone who turns completely white after being confirmed or confined. These are the appearances of negaim upon which depend all negaim.