256 THE NATURE AND TREATMENT OF 



each side of the spine to various parts of the body, and their ter- 

 minations are called " sentient, " this being the seat of sensation. 



The most important nerve, however, for our consideration, is 

 the sympathetic. It is supposed by some writers to be in itself 

 a complete nervous system. It originates in a branch issu- 

 ing from the base of the brain, and communicates with every 

 other nervous filament of the body. The connection takes 

 place in the following manner : The sympathetic nerve has at 

 various points a number of gangliform plexuses ; from these, 

 thread-like filaments arise, which radiate and connect with sim- 

 ilar ganglions found on the cerebral and spinal nerves. On 

 these divergent filaments we have other ganglionic structures, 

 which send branches to the liver, spleen, kidneys, etc. 



The sympathetic nerves of one side amalgamate with those 

 of the opposite, and this is their mode of communication. 



The nerves of the sympathetic system possess a certain de- 

 gree of power in exciting muscular contractions, as well as 

 sympathetic actions, in the various parts to which they are dis- 

 tributed. Carpenter has observed, that by " irritating a branch 

 of the sympathetic nerve immediately after the death of an 

 animal, contractions may be excited in any part of the alimentary 

 canal, from the pharynx to the rectum, according to the trunks 

 which are irritated ; in the heart, after its ordinary movements 

 have ceased, in the aorta, vena cava, and thoracic duct, in the 

 ductus choledochus, uterus, fallopian tubes, vas deferens, and 

 vesiculae seminales, etc. It is probable that the sympathetic 

 system not only thus brings the organic functions into relation 

 with the animal, but that it also tends to harmonize the former 

 with each other, so as to bring the various acts of secretion, 

 nutrition, etc., into mutual conformity." 



There are several orders of sympathetic nerves ; some pass' 

 into the parenchyma of the organic viscera ; and others are 

 distributed on the outer coats of arteries, continuing through- 

 out their minute capillary structures into the papillae. By this 

 arrangement the harmony between the internal, external, and 

 remote parts is perpetuated. 



Correct knowledge regarding the sympathetic relations pe- 



