Human and comparative anatomy, physiology, and hygiene . id. It occupies thefore part of the eye, behind the cornea. (Fig. 62.) Q. What is the aqueous humor ? Where is it situated ? 195. The crystalline humor lies in the central partof the eye. It is oval, dense, and composed of layerslike an onion. (Fig. 62.) Q. Describe the crystalline humor. 196. The vitreous humor occupies the larger andback portion of the eye. (Fig. 62.) Q. What is said of the vitreous humor 1 197. The iris is a curtain across the eye, before thecrystalline humor. It has an opening in the centre,called the pupil. The iris
Human and comparative anatomy, physiology, and hygiene . id. It occupies thefore part of the eye, behind the cornea. (Fig. 62.) Q. What is the aqueous humor ? Where is it situated ? 195. The crystalline humor lies in the central partof the eye. It is oval, dense, and composed of layerslike an onion. (Fig. 62.) Q. Describe the crystalline humor. 196. The vitreous humor occupies the larger andback portion of the eye. (Fig. 62.) Q. What is said of the vitreous humor 1 197. The iris is a curtain across the eye, before thecrystalline humor. It has an opening in the centre,called the pupil. The iris gives the blue, black, orgray color to the eye. (Fig. 62.) Q. Where is the iris situated ? What is the opening in thecentre called ? What does the iris give ? 84 ANATOMY, PHYSIOLOGY, AND HYGIENE. 198. The eye of a bee or fly is composed of manythousand facets, each of which has a nerve, so that it isan independent eye. Hence a bee or fly can see in alldirections without turning the head. (Fig. 63.) Q. What is said of the eye of a bee or fly ? Fig. Fig. 63. The compound eye of a fly or bee. 1. The facets, or lenses,without hairs. 2. The same with hairs. 3. The conical form of thefacets shown. 199. The coats give form to the eye; the humorschange the direction of the rays of light that pass to theretina; the iris regulates the quantity of light that entersthe eye. (Fig. 62.) Q. What is the use of the coats of the eye 1 The humors ?The iris ? 200. The muscles of the eye are six in are small, and produce the movements of this organ. Q. How many muscles has the eye, and what is their use f 201. The eye is protected from too great light, particles THE EYES. 85 of dust, and other substances by the eyebrows, eyelids,and eyelashes. Q. What parts protect the eye 1 202. The tears also afford protection by keeping the eyemoist, as well as aiding the removal of particles of matter. Q. What is the use of tears ? 203. Vision is improved by practice, like the othersenses ; bu
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectanatomycomparative
