Midrash su Levitico 13:15

6) (Vayikra 13:15) ("And the Cohein shall see the living flesh and he shall declare him tamei. The living flesh is tamei; it is leprosy.") What is the intent of this? I might think that limb tips that were revealed (by recession of the nega from them) rendered one tamei (by reason of impeding complete blossoming) only after the (complete) blossoming of a confirmed michyah in the beginning (i.e., before quarantine, as per the verse). Whence do I derive (that he is tamei) after blossoming of the same at the end of the first week (of quarantine), at the end of the second week, after exemption (at the end of the second week by reason of its remaining the same in appearance); after blossoming of confirmed white hair in he beginning, at the end of the first week, at the end of the second week, after exemption; after blossoming of confirmed spreading at the end of the first week, at the end of the second week, after exemption? (Whence do we derive that revelation of limb tips by recession of the nega renders all of these tamei? [Note: Chapter 4:6 discusses rendering one tahor]) From "And the Cohein shall see the living flesh and he shall declare him tamei. The living flesh is tamei" — to include all (of the above instances).

7) I might think that if one came all white (and he were quarantined, and no further signs of tumah appeared in him) and his limb tips were revealed after exemption — (I might think) that he were tamei; it is, therefore, written "it (is tamei") (to exclude the above). I would then exclude him, but I would not exclude one who came all white, whose limb tips were revealed either in confirmation or in quarantine. It is, therefore, written "it is tamei; it is leprosy," but he above is not tamei but tahor.