And the priest shall look on the disease in the skin of the flesh: and when the hair in the disease is turned white, and the disease in sight is deeper
than the skin of his flesh, it is a disease of leprosy: and the priest shall look on him, and pronounce him unclean.
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George Leo Haydock
Flesh. These two signs indicated the species of leprosy called volatile, or impetigo, (Menochius) resembling a scab, which did not penetrate the flesh or bones, as our leprosy or elephantiasis does. (Vales.; Chap. xix.)
Separated from society. Hebrew, "he shall contaminate him. "See ver. 11. (Haydock)
Some assert, that the physician was first to be consulted. But none but the priests could declare them unclean, or set them at liberty. After they had pronounced sentence, the lepers might apply for medicines to others.