Rambam - 1 Chapter a Day

These are the places in the human body which do not incur impurity because of a baheret: the inside of the eye, the inside of the ear, the inside of the nose, the inside of the mouth, the folds of the stomach, the folds of the neck, under the breasts, the armpits, the underside of the foot, a nail, the head and the chin where hair grows, and open boils and burns.

All of these surfaces do not become impure because of blemishes, nor can they be combined with blemishes. A blemish cannot expand into them; they are not considered as healthy flesh in the midst of a blemish, nor does the absence of tzara'at on them prevent a person whose entire body is afflicted from being placed in that category. These concepts are derived from Leviticus 13:2 which speaks of a blemish being "on the skin of one's flesh." None of the above surfaces can be considered as revealed flesh. Some of them are not flesh and some are flesh, but they are covered and not revealed.

The red portions of the lips are considered as "hidden places" and cannot incur impurity from blemishes.

When all the hair of the head and the chin fell off or a boil or a burn developed a scab, they may incur impurity due to a baheret, as we explained. Blemishes on these surfaces are not combined with each other, nor can a blemish on ordinary skin expand into them, nor are they considered as healthy flesh in the midst of a blemish. The absence of tzara'at on them does, however, prevent a person whose entire body is afflicted from being placed in this category.

When there is a baheret next to the head, the eye, the ear, or the like or next to a boil or a burn, it is pure. This is derived from Leviticus 13:3: "And the priest shall see the blemish in the flesh of the skin." Implied is that the entire area immediately outside the blemish must be ordinary flesh that is fit for the blemish to spread into.

The following are beharot that are pure:

a) A gentile who had a baheret and converted.

b) A baheret existed on a fetus and then the infant was born.

c) A baheret existed in a crease of a person's flesh and then it was revealed.

d) A baheret existed on the head and/or the chin where hair grew, and then all the hair fell off and the baheret was revealed.

e) There was a baheret on ordinary skin, either a boil or a burn formed on its place, and then they healed, and became like ordinary skin. Even though the initial and ultimate condition of the skin is susceptible to impurity, since it was pure in the interim, it remains pure.

In all the above instances, if the shade of the blemish changes, whether the whiteness becomes stronger or weaker, it should be given an initial examination. What is implied? A gentile had a baheret that was white like the membrane of an egg. After he converted, it became white as snow. Or originally, it was white as snow and after he converted, it became like the membrane of an egg, it should be given an initial examination. Similarly, when an infant is born, the creases of a person's skin straighten, a person's head or chin become bald, or a boil or a burn heal, if the shade of these blemishes change, they should be given an initial examination. If not, they are considered pure.

Until a person has been deemed impure, all questionable situations regarding blemishes are considered as pure except for the two questionable situations we mentioned already. When, however, a person has been deemed impure, a questionable situation is considered as impure.

What is implied? Two people came to a priest, one had a baheret the size of a gris and the other, one the size of a sela. He had both of them isolated. At the end of the week, they both had blemishes the size of a sela and it was not known which blemish increased in size, they are both considered pure. Not only does this apply with regard to two people, it also applies with regard to two blemishes on the body of one person. Even though a blemish on this person's flesh definitely increased, since it is not known which blemish increased, he is deemed pure until the identity of the blemish for which he will be deemed impure is known.

Once a person has been deemed impure, any questionable situation is also considered impure. What is implied? Two people came to a priest. One had a baheret the size of a gris and the other, one the size of a sela. He had both of them isolated. At the end of the week, they came to the priest and they both had blemishes that were larger than a sela. They are both deemed impure. If they both shrank to the size of a sela and thus the increase receded from one of them, since it is not known which one originally had the blemish of this size, they are both impure until both their blemishes recede to the size of a gris. This is what is meant by the statement when a person has been deemed impure, a questionable situation is considered as impure.

Similar concepts apply when a person had a baheret and there was white hair within it that had existed before the baheret and other hair that was turned white by the baheret and the priest does not know how to distinguish between the hair that existed before the baheret and that which was turned white. If the doubt arose while the person was in isolation, he is pure. If the doubt arose after he was definitively deemed impure, he remains impure even if one of the hairs fell off and he does not know which fell off, the hair that was sign of impurity or the other hair.

When a person comes to a priest and he sees that he needs to be isolated or that he should be released from the inspection process and before he isolates him or releases him, signs of impurity erupt, he should be deemed definitively impure. Similarly, if he saw that he had signs of impurity and before he deemed him definitively impure and told him: "You are impure," those signs of impurity disappeared, the stringent ruling should not be delivered. Instead, if he is coming for his initial examination or at the end of the first week, he should be isolated. If he is coming after the conclusion of his second week or after he has been released from the inspection process, he should be released.