LECTURE X 

 THE NERVOUS SYSTEM 



554. All the actions of the living body are governed, more or less, 

 by the nervous system, which consists of two distinct portions — the 

 cerebrospinal, and the sympathetic or ganglionic. The brain is the 

 great centre of the nervous system, and the special senses, such as 

 smell, taste, etc., are connected with and controlled by it. Two of 

 these special organs — i.e., the eye and the ear — will be noticed in this 

 lecture. 



555. The Cerebro-spinal system (Plate XXXVII., A to D) em- 

 bodies the brain, the spinal cord, and the nerves given off from each. 

 Those from the spinal cord are for sensation and motion, whilst 

 from the brain, as already indicated, there arise the nerves of special 

 sense. 



556. The Sympathetic or Ganglionic system (Plate XXX VII. , 

 E), that of the nerves of organic life, are not immediately under the 

 influence of the will, and are made up of a double chain of knots or 

 ganglia. They run through the length of the body, on each side of 

 the back-bone, and give off fibres to control the involuntary move- 

 ments of the internal organs, such as the heart and bloodvessels, 

 respiratory and digestive organs, etc., these fibres having free com- 

 munication with the spinal nerves. 



557. The Nerve Tissue itself is composed of both a fibrous and 

 a cellular structure. The latter (grey substance) is found in the 

 outer portions of the convolutions of the brain, and in the middle of 

 the spinal cord and the ganglionic nerve centres, while the fibrous 



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