אדם כי יהיה בעור בשרו, none of the verse in the chapters following may be interpreted in the way he sound when read superficially as the phenomena described do not correspond to any skin diseases we are familiar with, and are not subject to medical treatment. What applies to the human skin applies in the same degree to stains on clothing which are described her as well as to manifestations of “mildew” or something similar breaking forth from the walls of houses. The only criteria which we can apply to what is spelled out in these chapters 12-15 are those laid down by our sages of the Midrash, the Talmud, etc, all of which date back to the instructions received orally from Moses.

כי יהיה בעור בשרו, according to tradition, a reference to a skin irregularity on the skin of (surrounding) the beard or the head. Compare verse 29. The Torah had to use the expression

שאת to describe an elevation of the skin in the area afflicted. This is not an actual elevation but an optical impression, i.e. it is not as white as for instance בהרת. We know that בהרת represents the highest purest degree of the colour “white.” This is clear from Job 37,21 בהיר הוא בשחקים, ”although it is brilliantly bright in the sky.” This colour described as שאת is somewhat עמוקה, “deeper,” in the sense of “a lower degree of” בהרת the most brilliant kind of white.

ספחת, a word which is subordinate to שאת,or subordinate to the word בהרת.[something subject to disagreement in Negai-im. Ed.] This is based on Samuel I 2,36 ספחני אל אחת הכהונות “please assign me to one of the priestly duties.” Clearly, the word is used in a subordinate mode

לנגע צרעת, the area where the affliction surfaces is white skin as we know from Exodus 4,6 מצורעת כשלג, “encrusted with snowy white scales.” As we know snow is white.

ומראה הנגע עמוק, white.

ועמוק אין מראה, it is not the same kind of white as the other kinds of scales on the skin mentioned thus far.

צרעת היא, definitive, beyond doubt. The afflicted person has to remain in isolation until cured when he or she will offer bird-offerings.

ומחיית בשר חי, with a patch of undiscoloured flesh not like fully ripened skin but raw, like a piece of flesh in the middle of the afflicted scab.

שחין, our sages explained this as like the infected hot area of an injury on the flesh’s skin. There is another type of שחין, the result of a burning of the skin by fire.

נתק, the name applied to these kinds of scabs in the area where the hair grows.

ושער שחור אין בו והסגיר, if there had been black hair the person would be ritually completely pure and does not need to be isolated even for further examination purposes. This is spelled out clearly in verse 37.

פחתת, the word describes a kind of inflammation which eats away at the affected area.