ON THE GANGLIONS AND SYMPATHETIC NERVE. 515 



coccix, and above by the fifth and sixth pairs and by the brain, 

 constitute an elliptic periphery which embraces all the system 

 of ganglions and plexuses, and into which several cerebral 

 nerves penetrate, particularly the eight pair. 3d. The branch- 

 es or conducting plexuses would transmit sensation and voli- 

 tion, if they were perfect conductors; but they -may be consid- 

 ered as semi-conductors, and theganglio'ns as isolating bodies. 



There results from this two nervous systems and two spheres 

 of nervous activity: 1st, the animal sphere, in which the im- 

 pressions are perceived, where the volitions determine motion; 

 2d, the vegetative sphere, where the nervous activity is distri- 

 buted slowly, continually, and obscurely. In this system, the 

 impressions determine motion, without being propagated to 

 the animal centre. In the state of disease, however, the com- 

 municating cords and plexuses become conductors, the gan- 

 glions cease to be .isolating, the impressions are perceived, 

 and the motions are influenced by the animal centre. 



According to Reil also, in the magnetic sleep, the separa- 

 tion of the two nervous centres disappears, and the epigastric 

 nervous centre, the centre of the vegetative sphere, becomes 

 a distinct sense. 



Autenreith considers the sympathetic nerve as arising from 

 the brain and spinal marrow, but becoming more and more 

 independent in proportion as it is separated by plexuses and 

 ganglions, the reddish or grayish substance of the sympathetic 

 nerves conducting impressions and irritations with more diffi- 

 culty than the white. 



Weber has collected together many anatomical and physio- 

 logical arguments, to demonstrate that the sympathetic nerve 

 constitutes a particular system, which, independent of the 

 brain, has its centre within itself. 



Wutzer has observed; as well as Bichat and others, that the 

 mechanical irritation of the sympathetic nerve does not pro- 

 duce any appreciable effect; whilst a more powerful irritant, 

 as galvanism, determines pains and convulsions. 



Broussais considers also the intercostal nerve as a peculiar 

 system, a particular sensitive centre, which transmits impres- 

 sions to the animal sensorium, and consequently determina- 



