CONTENTS. 7 



Venous Blood Respiratory Labor Impurities of the Air Dust 

 Carbonic Acid Effects of Impure Air Nature's Provision for 

 Purifiying the Air Ventilation Animal Heat. 



CHAPTER IX. 



PAGE 



THE NERVOUS SYSTEM 148 



Animal and Vegetative Functions Sensation, Motion, and Volition 

 The Structure of the Nervous System The White and Gray Sub- 

 stances The Brain Its Convolutions The Cerebellum The Spi- 

 nal Cord and its System of Nerves The Anterior and Posterior 

 Roots TJie Sympathetic System of Nerves The Properties of Nerv- 

 ous Tissue Excitability of Nervous Tissues The Functions of the 

 Spinal Nerves and Cord The Direction of the Fibres of the Cord 

 Reflex Activity and its Uses The Functions of the Medulla Oblon- 

 gata and the Cranial Ganglia The Reflex Action of the Brain. 



CHAPTER X. 



THE SPECIAL SENSES 177 



The Production of Sensations Variety of Sensations General Sensi- 

 bility 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 t/ie 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 Func- 

 tion The Movements of the Eyeball The Function of Ac- 

 commodation 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 Ihe 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 Ventnloquy. 



