DISEASES OF THE NERVOUS SYSTEM. 



By W. H. Haebaugh, V. S. 

 [Revised in 1904 by Leonard Pearson, B. S., V. M. D.] 



The nervous system is the distinguishing feature of animal life; 

 without it there can be no intelligence, no instinct, no sensibility, no 

 perception; in fact, existence would be nothing more than vegetable 

 life. 



The senses — touch, taste, sight, hearing, smell — all depend on the 

 nervous system. Motion depends on it. A muscle can not contract 

 without receiving the stimulus from the nervmis system. For exam- 

 ple, if a nerve passing from a nerve center to a muscle is severed, the 

 particular muscle that is supplied by the cut nerve is paralyzed. 



The nervous system is often studied in two divisions — the cerebro- 

 spinal division and the sympathetic division. 



The cerebrospinal division consists of the brain and spinal cord, 

 nerves, and ganglia. The nerves of this division convey the impulses 

 of motion and sensation, and supply all parts which are under the 

 control of the will. For example, the voluntary muscular tissue 

 includes all the muscles which act as the will directs. Another 

 example, if anything comes in contact with any part of the skin, the 

 impression is immediately perceived. All the special senses belong 

 to this division. 



The sympathetic division consists of nerves and ganglia. The mus- 

 cular tissue, which acts independently of the will — as, for example, the 

 stomach, intestines, womb, blood vessels, ducts, etc. — is called invol- 

 untary muscular tissue, and receives nervous stimulus from the sym- 

 pathetic division. 



The brain, spinal cord, and the ganglia are the central organs of the 

 nervous system. The nerves conduct the nervous influence. The 

 nerves terminate differently according to their function. The termi- 

 nations are called end organs. The terminal end organs in the skin 

 and other parts endowed with sensation receive the impressions, which 

 are conveyed to the brain, where they are appreciated. They are so 

 sensitive that the most gentle zephyr is perceived. They are so abun- 

 dant that the point of the finest needle can not pierce the skin with- 

 out coming in contact with them, and the sensation of pain is instantly 

 conveyed to the brain. The terminal end organs of the nerves that 

 supply the muscles are different, as they give the impulse which is 



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