actions of this wonderful organ, we arrive amidst many mysteries, and must admit that perception is not explicable by laws which govern matter. Here spirit takes the light into its own mystic keeping, and leads man through wonders many, and vastly above the comprehension of the superficial.
The Diagram is the same section, though on a less scale than Dr. Franz's. It represents a horizontal section of the anterior part of the head, made in the direction of a line passing through the middle of the anterior aperture of each orbit, to show form of orbit; position of eye-ball; arrangement of muscles; the lachrymal organs; interior structure of globe; course of optic nerve; and formation of the image of an external object on the nervous membrane of the eye by means of the rays of light. The vessels and nerves are omitted.
1 Shows the lateral walls of the orbit.
2 The left eye-ball with five of the six muscles.
3 Is the superior.
4 „inferior.
5 „exterior.
6 „interior.
7 The superior oblique muscle (with its tendon passing through a loop of cartilage), which is affixed to the foremost part of the upper wall of the orbit, where this wall unites with the interior wall.
8 The lachrymal gland.
9 The conjuntiva, covering a portion of the anterior hemisphere of the globe and the interior surface of the eye-lids.
10 Small orifices, through which the tears pass into the lachrymal ducts.
11 A transverse section of the lachrymal ducts.
12 The ophthalmic artery, as it enters the orbit by foramen opticum.
