THE SYMPATHETIC SYSTEM 303 



2. Physiologically. The physiological relation is best indi- 

 cated by examples. A great many, if not all, the sympathetic 

 ganglia seem to receive their power to generate nerve force from 

 the cerebro-spinal system; there can be no proper nutrition of the 

 parts animated by cerebro-spinal fibers without the associated ac- 

 tion of vaso-motor sympathetic fibers 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 sympathetic 

 system, an increased amount of blood is thereby sent to the sali- 

 vary 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 considering secre- 

 tion, digestion, circulation, respiration, etc., serves to emphasize 

 their connection. 



