GENERAL PLAN OF DISTRIBUTION. 529 



lion or voluntary motion, but of that organic sympathy or sen- 

 sation, and those organic movements, which, to the knowledge 

 of every one, exists in the viscera of the abdomen, susceptible 

 of being but little influenced by the will, and which are 

 mainly concerned in the great processes of digestion, circu- 

 lation, and nutrition. Hence, from its manner of distribution, 

 the sympathetic has been called the nervous system of organic 

 life. The general, though not exclusive route of distribution 

 of its branches is along the outer surface of the arteries. At 

 the roots of the greater vessels, the nerves are collected in 

 such numbers, occasionally intermixed with ganglia, as to 

 form plexuses, which take the names of the arteries ; as the 

 hepatic, the gastric, mesenteric plexus, &c. For this reason 

 the sympathetic has been called by some, the vascular system 

 of nerves. The term of sympathetic, which is the more gene- 

 rally used, appears to be derived from the fact of this system 

 associating the different organs in separate sets or apparatuses, 

 so that they are enabled to work together in their healthy 

 condition, to the certain fulfilment of a common object. Thus 

 we have the stomach, the liver, the pancreas, the intestines, 

 and possibly the spleen, forming a combination for the purposes 

 of digestion ; the kidneys, the ureters, and the bladder, 

 for the removal of the urine : and this association is main- 

 tained through the agency of the different central plexuses or 

 ganglia, from which branches are sent to supply these different 

 organs. 



The sympathetic nervous system not only emits branches of 

 communication to the cerebro-spinal, but likewise receives 

 filaments from the latter in return, which are intermingled 

 with and distributed to the organs along with its own parti- 

 cular class of nervous fibres. This is especially the case in 

 regard to the neck, the thorax, and the pelvis, where the 

 voluntary and involuntary movements, though each at times 

 exercised alone, are nevertheless much mixed and inter- 

 mingled. 



But the viscera of the abdomen in which voluntary cerebral 

 power of all other parts can be least exerted, receive their 

 VOL. ii. 45 



