ON THE GANGLIONS AND SYMPATHETIC NERVES. 507 



rior is united to the ganglion only by loose cellular tissue. 

 Haase first made this observation, which has since been con- 

 firmed by Prochaska and Scarpa. The anatomists who pre- 

 ceded them thought that the two roots of the nerve concurred 

 in the formation of the ganglion. 



The membrane of the spinal ganglions, furnished by the 

 dura mater, appears more firm, more dense, and more solid 

 than that of the other ganglions. The ganglion itself is so 

 closely enveloped, that it appears very hard. The pulpy sub- 

 stance envelopes the medullary filaments more loosely than in 

 the others, and is more distinct and more easily separable. 



The medullary fasciculi having entered by the posterior or 

 internal extremity of the ganglion, divide into three, four, or 

 five white filaments. They diverge at first from each other, 

 then converge towards the other extremity. These filaments 

 unite with each other, so that each departing cord is formed of 

 filaments which probably come from several entering cords. 

 However, the number, the tenuity, and the confusion of the 

 filaments are not very great. The spinal ganglions have a sim- 

 ple texture compared with the others. 



The nervous fasciculi, collected together after leaving the 

 ganglion, unite intimately, at the distance of hardly two lines, 

 with those of the anterior root, to form the common trunk of 

 the spinal nerves: a trunk which itself has only a length of 

 one or two lines before dividing into the anterior and posterior 

 branches. 



The common trunk of each spinal nerve, at a little distance 

 from the ganglion, furnishes a simple branch, often double, 

 rarely triple, which goes towards the ganglion near the sym- 

 pathetic nervous trunk, and joins it in such a manner as to 

 establish the most intimate connexion between the nerves of 

 the spinal marrow, the spinal marrow itself, and the great 

 sympathetic nerve. Anatomists, and especially physiologists, 

 have frequently discussed the question, whether the branch of 

 communication comes from this or the other root. I have 

 seen, as well as Scarpa and Wutzer, that the simple or double 

 branch comes from the common inextricable trunk, and that, 

 when it can be traced, it is found to come from both roots. 



