_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._ CHAPTER XI. THE VOICE 227 _Voice and Speech--The Larynx, or the Organ of the Voice--The Vocal Cords--The Laryngoscope--The Production of the Voice--The Use of the Tongue--The different Varieties of Voice--The Change of Voice--Its Compass--Purity of Tone--Ventriloquy._ {8} CHAPTER XII. THE USE OF THE MICROSCOPE IN THE STUDY OF PHYSIOLOGY 236 _The Law of Tissues--Necessity of the Microscope--Different kinds of Microscopes--Additional Apparatus--Preliminary Studies--The Study of Human Tissues--Tissues of the Inferior Animals--Incentives to Study._ APPENDIX. POISONS AND THEIR ANTIDOTES 247 GLOSSARY 252 {9} LIST OF ILLUSTRATIONS