Seen here: a drawing of an alembic vessel.
What is an alembic vessel? Alembic vessels were used to distill liquids in order to extract certain components. Alembics consisted of two vessels connected by a tube; the vessels were made of either pottery or glass. (Imagine boiling sea water in one vessel, waiting for the condensation to drip through the tube and dry, and then collecting the remaining salt in the second vessel.) Alembics were also used to distill alcohol.
This is the only illustration in both volumes of 10a 131. I’m wondering why the scribe felt it necessary to sketch something which must have been familiar to many physicians.
For a lovely, in-depth piece about alembic vessels, see Fordham University’s digital exhibition on Medieval London here.