554 
ON THE NERVES AND BLOODVESSELS 
pora olivaria) by many filaments, which unite and form a cord 
of considerable size, and escapes from the cranium with the 
ninth and eleventh accessory pairs of Willis. In attentively ex¬ 
amining the pneumogastric of the ox at its origin, we see dis¬ 
tinctly that the roots of the eleventh or accessory pair mingle 
with those of the tenth, or pneumogastric, before these pene¬ 
trate into the nervous ganglion which is constantly found in 
the horse and the ox at the origin of the par vagum; and 
that these two pairs of nerves, the tenth and the eleventh, after 
having escaped from this ganglion, as well as from the spinal 
cord, remain intimately united for the space of six or seven 
centimetres (between two and three inches). 
The pneumogastric, after having separated from the eleventh 
])air, sends some fibres to the guttural ganglion, while some 
pharyngeal and other branches go to the cephalic artery; but it 
particularly furnishes two superior laryngeal nerves: an anterior, 
and the larger of the two, and which often supplies a pharyngeal 
branch; and a posterior nerve, smaller and longer. But that 
which is peculiar to the ox is the two anastamosing branches, 
with the recurrent and the pharyngeal, viz., the posterior one, 
the smaller and longer one, with a branch which seems to come 
from the recurrent. This anastomosis has a plexous character 
at the upper part of the first cartilages of the trachea above and 
behind the larynx. The superior laryngeal trunk, the larger of 
the two, unites itself with the recurrent, or inferior laryngeal, by 
means of a branch coming from the latter, and which passes 
under the thyroid cartilage for the purpose of uniting with the 
superior and anterior laryngeal nerve. The anastomosis of these 
three branches, destined for the larynx, forms a plexus situated 
at the back of that organ, and under the lateral origin of the 
trachea, whence springs a retrograde cord, which abuts on the 
inferior surface of the oesophagus, and ramifies there. 
Each principal cord of the two pneumogastrics follows the 
course of the jugular vein in company with the trisplanchnic 
nerve. Having arrived at the inferior cervical ganglions, the 
vagal nerves separate from the trisplanchnics. Both of them 
furnish branches to the trachea and to the cardiac plexus, but 
the right pneumogastric particularly sends a considerable branch 
to the auricles of the heart. 
There likewise, at this situation, emanate from these nerves 
the inferior laryngeal or recurrent nerves, right and left. 
The two pneumogastrics then go to form the bronchial plexus. 
They each receive, in this place, a trisplanchnic branch coming 
from the plexus, which surrounds the inferior cervical ganglion, 
and sometimes springs from the ganglion itself, as we saw in 
