The eye's spherical lens, and boiling an eye to dissect it
The pupil centred in a spherical lens that gathers all images; a dissection method
Two notes on the eye occupy this folio. The first sets the pupil at the centre of the lens, which has the form of a portion of a sphere and, being spherical, takes in all the images of objects and sends them through the pupil to the place where vision is formed. The second gives a dissection method: to open the eye without spilling its humor, boil the whole eye in egg white until hard, then cut egg and eye across so the lower half loses nothing. A large diagram shows a hatched spherical eye with radiating lines and, at the right, a small eyeball on its axis.
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The spherical lens gathers all images to the pupil
The pupil sits in the middle of the lens, which has the form of a portion of a sphere and receives the pupil at the centre of its base. Being part of a sphere, this lens takes in all the images of objects and sends them, through the pupil, inside to the place where vision is formed.
Boiling the eye in egg white to dissect it
In the dissection of the eye, to see it well inside without spilling its humor, put the whole eye into egg white and boil it. Once it is hard, cut the egg and the eye across, so that the lower half spills nothing. The block carries the diagram label 'n e'.
Diagram of the spherical eye and its rays
A large drawing in the lower half shows a hatched spherical eye crossed by radiating lines, with a small eyeball set on an axis to the right. It illustrates how the spherical lens of the text gathers rays from objects toward the pupil.