3O4 THE NERVOUS SYSTEM 



not even of the nerve cells and fibers themselves; in reflex 

 action the afferent impression may be conveyed by a cerebro- 

 spinal fiber and reflected through a sympathetic, or vice 

 versa; when one hand is thrust into hot or cold water the 

 temperature of the opposite hand may be raised or lowered, 

 impressions having been carried to the center by cerebro- 

 spinal and reflected by sympathetic fibers, not only to the 

 immersed hand, but to the other as well ; food is taken into 

 the mouth, impressions are carried by nerves of common 

 sensation to the brain and are reflected through the sympa- 

 thetic system, an increased amount of blood is thereby sent 

 to the salivary glands and an increased secretion supervenes ; 

 one smells savory articles and the mouth waters, etc. 



Examples could be multiplied ad infinitum to establish 

 the cooperation existing between the two systems. What 

 has been incidentally and indirectly said on this point in con- 

 sidering secretion, digestion, circulation, respiration, etc., 

 serves to emphasize their connection. 



