ON THE GANGLIONS AND SYMPATHTIC NERVE. 511 



little ganglion or arch, in which the two nerves unite, and 

 which furnish some delicate filaments to the environs of the 

 anus. 



The internal branches of the sympathetic nerve are distri- 

 buted, some directly upon the arteries, and form plexuses, the 

 others, in much greater number, reach the median line, and 

 form there, in uniting to those of the opposite side, median 

 plexuses or ganglions (the cardiac and creliac), which commu- 

 nicate with the branches of the pneumo-gastric nerve, which 

 furnish secondary plexuses or ganglions, and terminate in the 

 heart, the aorta, the digestive canal, the urinary and genital 

 organs, but especially in the arteries of these organs. 



808. Rare interruptions, -and perhaps not well observed, 

 in the trunk of the sympathetic nerve, have induced some 

 anatomists to regard- the existence of this trunk as a circum- 

 stance of little importance. There is exaggeration in this 

 opinion. However, its roots are very certainly in the spinal 

 nerves, and not in the vidian nerve and the sixth pair. 



The branches of the sympathetic nerve, differ not only from 

 tfiose of the other nerves, but they differ very much from each 

 other: each ganglion and especially each plexus of branches 

 has its proper or peculiar character. 



The sympathetic nerve has been considered, by Scemmer- 

 ing especially, as the nerve of the arteries: in truth the arteries 

 receive many branches from it; but the muscular tissue of the 

 heart, that of the digestive canal, the mucous membrane of this 

 canal and the .urinary and genital passages, the ligaments, the 

 bones even of the vertebral column, receive filaments from it. 

 It is remarkable that the veins, the lymphatic vessels and 

 glands are deprived of them, as well as the serous membranes. 

 They are found, on the contrary, in the long muscles of the 

 neck, in the intercostals, and the diaphragm. 



809, The spinal ganglions with their nerves, are the first 

 parts of the nervous system that are visible. 



The ganglions and the nervous trunk of the trisplanchnic 

 are apparent in the foetus after the third month. The coeiiac 

 ganglions and the splanchnic nerves, which are in a manner 



their roots, develope themselves a little less quickly than the 

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