424 THE NERVOUS SYSTEM 



Diseases of the nervous system. — Nerves. The sheaths which 

 inclose the axis cylinder may become the seat of inflammation. 

 The result is intense pain and various forms of nervous disease, 

 according to the extent and nature of the inflammation. Among 

 diseases of this nature are included all forms of neuritis, tooth- 

 ache, etc. 



Spinal cord. — Injuries to the spinal cord or the introduction 

 of certain forms of bacteria may result in the destruction of the 

 whole or part of this organ. The result is paralysis of the 

 parts supplied by the affected portion. Such diseases are usually 

 slow in action and often incurable. 



Brain. — Anything which affects the nerve cells of the brain, 

 such as pressure, narcotics, worr^-, lack of work or sleep, etc., is 

 boimd to result in disturbed mental action. Such influences may 

 result in sleeplessness, hysteria, lack of self-control, irritability, 

 and even in total loss of control or insanity. Interference with 

 the blood supply and pressure may produce fits or apoplexy. In 

 short, so sensitive is the brain to external influences that its encase- 

 ment in the bony cranium is none too strong a protection for this 

 delicate structure and any interference with its structure is attended 

 Tsdth serious results. 



Alcohol and the Nervous System. 



Stages in intoxication. — It is a fact known to everyone 

 that alcohol in any quantity affects the nervous system 

 almost immediately. It is noticeable that moderate quan- 

 tities have apparently a stimulating eifect upon the various 

 centers of speech, thought, and action. The winebibber 

 becomes exhilarated, his speech flows more rapidly, his wit 

 appears keener, and he is conscious of a sense of freedom 

 from restraint. If the amount of alcohol is increased con- 

 tinuously, this stage of apparent stimulation is soon followed 

 by excessive exhilaration. The subject becomes still more 

 talkative and his freedom from restraint manifests itself 



