Boil, to
To boil, as in Genesis 25:29, signifies to heap up, referring to the first state of the natural man who is regenerating where doctrinals are heaped together in his memory. (Arcana Coelestia 3316)
In Exodus 9:31, this signifies truth in the exterior, natural part of man. (Arcana Coelestia 7600, 7604)