CHAPTER X.

THE SPECIAL SENSES 177

_The Production of Sensations--Variety of Sensations--General Sensibility--Pain and its Function--Special Sensation, Touch, Taste, Smell, Sight, and Hearing--The Hand, the Organ of Touch--The Sense of Touch--Delicacy of Touch--Sensation of Temperature and Weight--The Tongue the Organ of Taste--The Nerves of Taste--The Sense of Taste, and its Relations with the other Senses--The Influence of Education on the Taste--The Nasal Cavities, or the Organs of Smell--The Olfactory Nerve--The Uses of the Sense of Smell--The Sense of Sight--Light--The Optic Nerve--The Eyeball and its Coverings--The Function of the Iris--The Sclerotic, Choroid, and Retina--The Tears and their Function--The Movements of the Eyeball--The Function of Accommodation--The Sense of Hearing and Sound--The Ear, or the organ of Hearing--The External, Middle, and Internal Ear._