*1 Rashi(Ex09-09a) simply translates it as boils (Ex09-09a).
   But the root SHACH means PIT, LOW etc.
   So a natural connection is that BOILS create
   abcesses in the skin which look like pits
   Here we use a derivation from the ROOT


*2 Rashi (Ex09-09b) explains the Biblical phrase
   BOILS THAT SPROUT BUBBLES to refer to pussy boils
   Hence the Talmuds inference that Egyptian boils were
   dry and itching inside the skin but pussy outside.

   The root Beth-Ayin-Hey seems to mean a BUBBLE LIKE
   APPEARANCE and can refer to
   -----------------------------------------------
   Isa64-01 Fire BUBBLING (STEAMING) Water
   Isa30-13 A MULTI-CRACKED high wall
   Ovad1-04 Its treasured places are MULTI-CRACKED
   -----------------------------------------------
   The bubbles and cracks have a BUBBLE LIKE appearance
   This would also be a fitting description of BOILS.

   Hence by using this OTHER VERSE we are justified in
   explaining other verses with EGYPTIAN BOILS as meaning
   PUSSY BOILS. See the Rashi on Dt28-27a (*10)

   THe idea of naming items by their APPEARANCE occurs
   in all languages. Consider the English metaphors
   ------------------------
   brainSTORMING of ideas
   SURFING       the web
   ------------------------

   Other examples may be found at
   http://www.RashiYomi.com/naming-8.htm

*3 We can approach this using two techniques
   -- OTHER VERSES
   -- COMMON ROOT MEANINGS

   First we look at OTHER VERSES
   We already showed that the CONTEXT of Dt28-27 refers to
   -------------------------------------------------------
   EGYPTIAN BOILS, hemmoroids and GARAV that are incurable
   -------------------------------------------------------

   Thus the VERSE shows that GARAV means boils
   (Dt28-27a)

   A more advanced analysis can be obtained using
   Rashis 2 letter theory as modified by me where
   the 3rd letter also has a meaning

   The root of GARAV is DRAGGING (GRR) INSIDE (BI) and
   would refer to a PSORAISIS like condition where
   there was constant itching and an urge to SCRATCH
   (SCRATCH = A DRAGGING MOTION). Other terms for
   PSORAISIS also focus on scratching.

   To analyze this root GRAV we show that GARAR does
   mean to DRAG. Here are some verses
   ----------------------------------------------
   1Kings7-9  Dragged(Cut) by Saws
   Jer30-22   a Dragging storm(Tornado)
   Lv11-07    the throat that DRAGS the food down
   -----------------------------------------------

*4 We again can use 2-4 techniques here.

   INFERENCE FROM A VERSE
   ----------------------
   Dt28-27 states that GOD STRIKES WITH EGYPTIAN BOILS
           WITH HEMORROIDS GARAV AND CHERES THAT CANT
           BE HEALED

   Thus the context shows that CHARES means a DISEASE,
   probably a skin disease

   INFERENCE FROM ROOTS
   --------------------
   Cheres means CLAY UTENSILS or CLAY FRAGMENTS. CLAY
   because of its soft nature was frequently used to
   SCRATCH. Thus the root CHERES refers to the SUBSTANCE
   used for SCRATCHING. Thus CHERES would probably refer
   to a PSORAISIS like condition where there was itching

   NAMING BY SUBSTANCE
   -------------------
   At http://www.RashiYomi.com/naming-8.htm we give several
   examples of items named by SUBSTANCE, what they are made
   of. For example
   ------------------------------------------------------
   GLASSES  What you see with
   LINOLEUM A type of floor
   IRON     A type of garment fixing device
   ------------------------------------------------------
   In each case the item is named by its substance.

   OTHER VERSE INFERENCES
   ----------------------
   Having established that CHERES refers to PSORAISIS
   we can then transfer this meaning to Lv21-20. This
   is in fact what Rashi does on Lv21-20.

   We can also infer from the OTHER VERSE Ex09-09 that
   EGYPTIAN BOILS can be DRY INSIDE BUT PUSSY OUTSIDE

*5 The proper procedure here is to identify what is
   clear and what is not clear. We first use the
   technique of VERSE INFERENCE

   VERSE INFERENCE
   ---------------
   Ex09-09 the EGYPTIANS received a plague of BOILS
           that sprout PUSS

   Dt28-27 God will strike with EGYPTIAN BOILS with
           GARAV and CHARES

   Lv21-20 If a person has a GARAV or YALEFETH

   The net effect of the above 3 verses is that YALEFETH
   is probably like GARAV which appears to be like
   EGYPTIAN BOILS which is a PSORAISIS condition.


   ROOT INFERENCE
   --------------
   The root of YALEFETH is not clear. I would suggest it
   comes from Lamed-Pay-Tauv which means to ENTANGLE as in
   -------------------------------------------
   Ju16-29 Samson ENTANGLED his arms on the pillars
   Ruth3-8 The man ENTANGLED when he discovered the woman
   Job6-18 The rivers ENTANGLE their paths
   -------------------------------------------

   In all these verses LAFETH seems to mean a DOUBLING OVER
   NON STRAIGHT PATH.

   Thus YALEFETH would refer to an ENTANGLING DISEASE

   In fact PSORAISIS is known for this: It can come and go
   in periods. It is also known for its persistence(It
   entangles the person his whole life(It is also incurable)

   The above analysis on root is conjectural. It is not the
   SOURCE OF MEANING. Rather the proper approach is that
   the source of meaning is the inference from the other
   verses. The analysis of root meaning is then given
   afterwards as a conjecture. We however are sure of
   the meaning from the OTHER VERSES.

   Rashi himself mixes several levels of inference together
   - Rashi uses other verses which are clear
   - Rashi uses root meanings which are conjectural
   - Rashi cites advanced talmudic analysis *11

   Again: The proper procedure is to identify the meaning
   from the other verses. The other statements can then
   be taken as more conjectural.

*10 Beth-Ayin-Hey can also mean to seek. But Hebrew uses
    the word PLOW to refer to SEEKING. Hence to BUBBLE
    could also mean to SEEK.

    The common denominator to PLOWING A THOUGHT and
    BUBBLING A THOUGHT is to look at it from several
    angles and make several breakthrus. The PLOWED
    mental terrain metaphorically looks like a BUBBLED
    water surface

*11 The Talmud goes into the type of PSORAISIS involved.
    - It is clear from Ex09-09 that EGYPTIAN BOILS are
      pussy outside

    - It is clear from Dt28-27 that CHERES, a SCRATCHING
      disease is DRY (Which is why you scratch)

    - Thus the Talmud states that BOILS are
      -- pussy outside
      -- dry inside

    - The Talmud conjectures that CHERES which means CLAY
      which is what people scratch with refers to a
      PSORAISIS which is
      -- dry inside
      -- dry outside

    - The Talmud also conjectures that GARAV which we
      said means a DRAGGING FEELING INSIDE refers to
      any PSORAISIS that is DRY INSIDE (The talmud also
      gives rules when GARAV means DRY INSIDE BUT PUSSY
      OUTSIDE and when it means DRY INSIDE AND DRY
      OUTSIDE).

    This of course is advanced analysis. A proper discussion
    would require a discussion of PSORAISIS. I simply brought
    this down to show how Rashi spanned the SIMPLE MEANING
    based on other verses as well as the ADVANCED MEANING
    based on subtle root meanings