of the chest in breathing, speaking, and expression. 287 
direct experiment, and the induction from anatomy, arise very 
nearly together. Their origins are not in a bundle, or fasci- 
culus, but in a line or series, and from a distinct column of the 
spinal marrow. Behind the corpus oliv are, and anterior to that 
process which descends from the cerebellum, the corpus resti- 
forme, a convex strip of medullary matter, may be observed, 
and this convexity, or fasciculus, or virga, may be traced 
down the spinal marrow, betwixt the sulci, which give rise 
to the anterior and posterior roots of the spinal nerves. 
This portion of medullary matter is narrow above where 
the pons V arollii overhangs it. It expands as it descends; 
opposite to the lower part of the corpus olivare it has reached 
its utmost convexity, after which it contracts a little, and is 
continued down the lateral part of the spinal marrow. 
From this track of medullary matter on the side of the 
medulla oblongata, arise in succession from above downwards, 
the portio dura of the seventh nerve : the glosso-pharyngeus 
nerve : the nerve of the par vagum : the nervus ad par vagurn 
accessorius ; the phrenic, and the external respiratory nerves. 
It is probable that the branches of the intercostal and lum- 
bar nerves, which influence the intercostal muscles and the 
muscles of the abdomen in the act of respiration, are derived 
from the continuation of the same cord or slip of medullary 
matter. Nor will it escape observation, that the nerves called 
phrenic and external respiratory, though coming out with 
the cervical nerves, do, in all probability, take their origin 
from the same portion of the medulla spinalis with the ac- 
cessory nerve. 
The intercostal nerves, by their relations with the medulla 
oblongata, are equal to the performance of respiration, as it 
