Chullin 105: Handwashing Between Meat and Milk; Salt

We learn about washing the hands around food.  The first time that we wash is mayyim emtz'iyim, washing during the meal.  Rav Nachman explains that we are not required to wash between courses of a meal unless a cooked meat dish and cheese are both being served. In that case, which is seemingly forbidden, washing between dishes is necessary.

To elucidate, the Rashbam teaches that Rav Nachman is describing the difference between a meal consisting of two doses of meat or milk, where no washing is needed, and a meal where a milk dish is followed by a meat dish, where washing would be required.  A milk dish would never be permitted to follow a meat dish.  Rabbeinu Tam suggests that Rav Nachman is talking about a meat dish that follows a milk dish.  We learn that as long as no actual meat or mil products are consumed, only when there is the "taste" of meat or milk in a dish, there is no need to wash our hands.  If actual cheese is being eaten after meat was eaten, we would be required to separate the two by washing.  The Rema accepts the Rashbam's position and it is still Halacha to wait a significant amount of time between eating meat and milk dishes.

The second type of washing is Mayyim acharonim, washing after the meal.  Rav Yehuda ben Rabbi China explains that this is essential because the melach sodomit, salt, could blind you if left on your fingers.  Abaye adds that this type of salt mixed with ordinary salt would pose serious medical danger.

Steinsaltz notes that this seems to refer to Magnesium Chloride (MgC12) which is found in the Dead Sea.  Both of these elements can be mixed with Sodium Chloride (NaCl), ordinary salt, which is produced in Sodom near the Dead Sea.  These are poisonous substances which could infect the eye of someone who inadvertently rubbed his or her eye with the dangerous material.