144 | ANTHROPOLOGY. 
be carefully divided, the latter will be found equally apparent. The creat 
distinction depends on the occurrence of numerous ganglions, both on the 
principal cords as well as on their branches; each ganglion is invested with 
a firm capsule, which is continuous with the sheath of the afferent and effe- 
rent nerves. ‘This capsule is surrounded by areolar tissue and blood-vessels; 
the latter ramify on and pierce the capsule; the internal surface of the latter 
is vascular, and may, on the larger ganglions, be separated as a vascular 
membrane from the external fibrous layer, and is analogous to the pia mater 
on the cerebro-spinal axis. The mass of a ganglion is composed of a plexus 
of nervous filaments, with a variable quantity of vesicular or grey neurine: 
the afferent nerves divide into numerous fibrille, which pass in the most 
varied directions, and re-unite most probably in different combinations, the 
interstices being filled with capillary vessels and grey neurine. Whether 
the efferent nerves consist of those filaments only which composed the affe- 
rent, or whether additional fibres are added to these in the ganglion, it is, 
in the present state of our knowledge, difficult if not impossible to deter- 
mine. ‘The only material difference to be observed between the structure 
of the ganglions of the sympathetic and those of the cerebro-spinal system 
is, that the latter appear in general to be less red and vascular, and to con- 
tain less of the vesicular or grey neurine; the interlacement of white fibres 
is more obvious in them, and constitutes the greater portion of each, par- 
ticularly of the spinal ganglions. 7 
Pl. 188, fig. 18, upper part of the great sympathetic nerve: ’, uppermost 
cervical ganglion; *’, branches from it to the accessory nerve; **, junc- 
tions with the cervical nerves; *, branch of the vagus; °, upper branch of 
the first cervical ganglion; °, communicating threads to Jacobson’s nerve; 
*, threads to the otic ganglion; *, threads to the oculomotor; °, threads to 
the vidian nerve; “, spheno-palatine ganglion with its branches; “, pharyn- 
geal and carotid branches of the first cervical ganglion; ”, glosso-pharyn- 
geal nerve; *, pharyngeal plexus; ", long or superior cardiac nerve; ™, a 
cardiac nerve from the vagus; *, middle cervical ganglion; *, its upper 
branches, one of which unites with the first cervical ganglion or with the 
main trunk, two others with the cervical nerves; *, middle cardiac nerve; 
” its connecting threads, with the pharyngeal branch of the tenth pair; 
* inferior cervical ganglion; *, its connexion with the brachial plexus; 
*° branches passing into the vertebral canal with the vertebral artery; 
** branches connecting it with the middle cervical ganglion, of which one 
passes before, the other behind the subclavian artery; ”, lowest cervical 
ganglion; *, union of the tenth pair with the cardiac plexus; ”, plexus at 
the arch of the aorta; “, plexus between the trachea and the pulmonic 
artery; *, tracheal branches penetrating into the lungs; “”, pulmonic 
plexus (from the tenth pair) and the connexion with the cardiac plexus; 
* anterior, “, posterior cardiac plexus; ***, two thoracic ganglions ; 
**35 branches to the descending aorta; *, connexion of a thoracic ganglion 
with an intercostal nerve; “, great splanchnic nerve. Jig. 14, lower por- 
tion of the sympathetic nerve: *"', three thoracic ganglions, with their 
roots proceeding from the spinal nerves; **, branches descending to the 
830 
