Stowell.] 100 [March 2, 
by lapping, in which animals the prehension of food is impossible after 
section of the N. hypoglossus. Longet’s experiments upon the ento- 
cranial trunk after section demonstrated the presence of excitability 
without sensibility ; Mayo and Magendie proved the presence of sensi- 
bility in the ectocranial nerve. We are forced to accept a mixed function 
in this nerve or to attribute its sensibility to the accessions from the 
myelic nerves. 
The section of the N. hypoglossus destroys movements of the tongue 
without disturbing the tactile or the ‘gustatory sensibility [Longet, Anat- 
omie et Physiologie du Systéme Nerveux, t. ii, p. 266]. 
The sensibility of the hypoglossus seems to be muscular rather than 
mucosal. Since the section of the N. vagus and the N. glosso-pharyn- 
geus is attended by loss of sensibility over the entire surface or dorsum 
of the tongue, although the N. hypoglossus is intact. Panizza’s experi- 
ments, confirmed by later observations, establish the paralysis of the 
pharyngeal muscles involved in deglutition by severing the N. hypo- 
glossus. The vaso-motor function of the N. hypoglossus is seen in the 
dilatation of the vessels of the tongue when the nerve is severed ; it is 
questionable whether the fibres to which this function is referable are 
not received from the myelic or the sympathic nerves. 
The connection of the N. hypoglossus with distinct articulation is 
demonstrated by experiment and confirmed by pathological evidence. 
The prominent role in pronunciation performed by the tongue evinces 
the importance of this nerve in expressing thought by articulate lan- 
guage. 
DESCRIPTION. 
Ectal Origin and Entocranial Relations.—The N. hypoglossus has its ectal 
origin by several (12-16) funiculi along a depression line about 4 mm. lat- 
erad of the ventri-meson, and which marks the dorsal border of the cau- 
dal half of the area elliptica; these funiculi are grouped into two more or 
less distinct bundles which are separated by the first dorsal ramulus of 
the A. cerebellosa caudalis. The cephalic bundle embraces 8-12 funic- 
uli (when the arteriole is represented by two vessels this cephalic bun- 
dle is again divided into two nearly equal portions) ; the caudal bundle 
includes about 6 funiculi, the caudal funiculus having its ectal origin 
at the cephalic border of the ventral root of the first cervical nerve, just 
entad of the A. cerebellosa. 
The ectal origin resembles the ventral root of a myelic nerve. 
Foramen of Exit.—The confluence of these funiculi forms a nerve trunk, 
which takes its exit by the foramen condylare. 
Ectocranial Trunk.—The ectocranial course is immediately caudad, lies 
dorsad of the A. carotidea and entad of the V. jugularis as far as the A. 
occipitalis. The central 5-8 mm. of the ectocranial trunk are intimately 
involved in the gangliform plexus (Fig. Pl. gang.) which is made by 
the interlacing fibres of the associated glosso-pharyngeus, vagus, acces- 
