(Chapter 12) Footnote 52:

The 1555 edition adds here that the branches of the carotid arteries rest upon these passages or depressions “just as if they had been carved out primarily for that purpose, and the phlegm itself flowed along the arteries. The middle surface of the cuneiform bone where the square depression marked M is located, together with the depressions containing the branches of the sleep arteries, is not porous on its outermost surface or filled like a sponge with foramina; much less does phlegm flow into it and slowly drip through as through a sponge (as is Galen’s opinion), as we learned in the sixth chapter with the account of the entire cuneiform bone.” The reference to Galen is explained in note 47 above.