450 



SYMPATHETIC NERVE. 



many of the glands : they have been seen by 

 Liulwig on the nerves of the kidney ; also by 



Fig. 296. 



Fourth thoracic ganglion of Rabbit ; showing the course 

 of the fibres contained in the communicating branch 

 after reaching the sympathetic. 



A B, main cord of sympathetic ; A, cephalic, 

 B, pelvic extremity; c, communicating trunk; g, 

 gang-Home corpuscles; a, portion of the fibres in 

 the communicating' branch passing towards the 

 pelvic extremity ; b, ditto passing towards the 

 head. (Magnified 70 diameters.) 



Pappenheim on the nerves distributed to the 

 supra-renal capsules. Schaffner* has also ob- 

 served ganglionic corpuscles from which 

 nerve-tubes proceeded, in the substance of 

 the lymphatic glands. Small ganglia have 

 also been described by Remak as occurring 

 on the nerves distributed to the bronchi : 

 they have also been observed by Kolliker. 

 The latter observer believes that he has seen 

 nerve-tubes arise from them. 



From the observations of Purkinje* it 

 would appear that numerous fibres of the 

 sympathetic pass to the cerebro-spinal mem- 

 branes. In the dura mater of the cranium he 

 describes the nerves as most abundant in the 

 neighbourhood of the trunks of the three 

 meningeal arteries. Most of them accom- 

 pany the vessels ; but there are also others 

 which leave them and ramify in the mem- 

 brane. In the pia mater of the cerebellum 

 the nerves which branch separately from the 

 arteries are not so numerous as in the pia 

 mater of the cord. The nerves in the pons 

 and cerebrum belong exclusively to the ar- 

 teries : no trace of nerve-fibres was seen in 



* Vcrmischte Bcobachtungen in Henle und 

 Pfeuffer's Zeitschrift, band vii. p. 177. 

 t Miiller's Archiv. 1845. 



the choroid plexuses. Around the vena 

 Galeni magna they form a dense plexus which 

 passes into the tentorium cerebelli, and seems 

 to belong to it rather than to the venous 

 system. The nerves in the pia mater of 

 the cord unite with those of the cerebellum 

 and pons. In the pia mater of the spinal 

 cord the nerves are more abundant than in 

 any other part of the cerebral membranes ; 

 they run singly or in bundles of two and 

 three ; others contain from thirty to fifty fila- 

 ments. Sometimes fibres leave the bundles, 

 forming loops and returning to the same or to 

 a different bundle. The largest bundles are 

 situated near the anterior spinal artery, which 

 they entwine; and some pass from this into 

 the process of the dura mater in the anterior 

 fissure, and form loops in the same. Other 

 large bundles, running mostly in a longitudinal 

 direction, are situated near the ligamentum 

 dentatum and posterior median line of the 

 cord. Near the origins of the spinal nerves 

 the bundles of sympathetic fibres are not 

 so numerous and are also smaller. Some of 

 these fibres spring from the cerebro-spinal 

 nerves, and enter with the arteries through 

 the intervertebral foramina. In the perito- 

 neum nerve-fibres have been described by 

 Bourgery* as existing in considerable num- 

 bers. They have also been observed by 

 Luschka.-f- Nerve-fibres are also abundant 

 in the periosteum, both that which invests the 

 shafts of the bones and the articular extremi- 

 ties of the same, as shown by the observations 

 of Pappenheim.J They are chiefly situated 

 in the outer part of the membrane, and either 

 run in company with the vessels or are situ- 

 ated upon them. They terminate in loops. 

 Nerves also exist, according to the same 

 author, in the cellular tissue which surrounds 

 the ligaments, penetrating these along with 

 the arteries, and terminating in a series of 

 plexuses and loops. In the tendons they are 

 also sometimes present. Wherever (accord- 

 ing to Pappenheim) vessels pass to ligaments 

 or tendons, nerves pass also. 



DEVELOPMENT. In the cow's embryo of 

 8i lines in length, the gangliated cord of the 

 sympathetic in the thorax was observed, by 

 Kiesselbach , on either side of the spinal 

 column in the form of a thick cord, presenting 

 numerous inequalities. In the pig's embryo, 

 eight lines in length, it presents, according to 

 Valentin, the same aspect. It seems, at this 

 period, to consist of a series of small ganglia 

 placed almost in juxta-position to each other, 

 the interval between the individual ganglia 

 not being very distinct. In another embiyo, 

 measuring about thirteen lines in length, Bis- 

 choff found the gangliated chain distinctly 

 formed, not only in the thoracic, but also in 



* Comptes rendus, 1845, p. 566. 



f Luschka, die JStructur des Serosen Haute des 

 Menschen, quoted in Canslatt's Jahresbericht. 



J Miiller's Archiv. 1843. 



Disser. Syst. Histor. Formationisac Evolution! 

 Ncrvi Sympathies : Munich, 1835 ; quoted in 

 ]5ishoffs Entmkelung und gcschichte, French 

 Translation. 



