374 
P. R. BILLINGSLEY 
TABLE 2 
AND S. W. 
Branch to the vagus nerve 
RANSON 
ane Aone NUMBER OF eAcatin © DIAMETERS OF MYELINATED FIBERS 
MILLIMETERS MILLIMETER 1.5 to 3.3 rm 3.3 to 4.5m 4.5 to 6.6 
per cent per cent per cent 
I 0.0029 18 5939.25 67 28 5 
I 0.00027 11 39604. 25 100 
5 0.0019 1 510.45 100 
IV 0.0018 0 
V 0.0021 97 45547 .75 100 
VI 0.0018 0 
1X 00068 0 
one instance as many as four of these twigs were found. In all 
other cases there was only one. 
In two cases there was no branch to the nodose ganglion, but 
instead a short branch was given off to the superior laryngeal 
branch of the vagus just after it had left the ganglion, and seemed 
in these cases to replace the usual branch. 
In table 2 we see that the area of the cross-section of the 
branch or branches of communication between the superior cervi- 
cal ganglion and the vagus nerve was very much less in Cats II 
and IX than in the others. In these cases it is probable that an 
additional communicating branch was overlooked when the dis- 
section was made. Irrespective of this variation in size, there 
was a great variation in the number of myelinated fibers; one 
nerve contained ninety-seven of them and another nerve of about 
the same size contained none. There was an equally great 
variation in the number per square millimeter. In most cases 
all of the fibers measured 1.5 to 3.34, but in one nerve there 
were some fibers between 3.3 and 6.64. A comparison of tables 
1 and 2 shows no essential difference between the myelinated 
fiber content of the branches to the cervical nerves and that to 
the vagus. 
The depressor nerve (7) is sometimes a branch of the superior 
laryngeal nerve. It follows the sympathetic trunk and vagus 
nerve through the neck into the thorax. Not uncommonly the 
fibers of this nerve run to the superior cervical ganglion and leave 
