Light micrograph of a section through an eye from a developing fetus. From right to left, this view shows the cornea, part of the iris, the developing lens (rounded area left of centre), the retina (upper and lower centre), and the cavity between the lens and retina, the vitreous body. The developing lens has a surface population of cells that progressively multiply and elongate into long lens fibres that make up the substance of the lens. Magnification x50 when printed at 10 cm.