3i2 P. R. BILLINGSLEY AND S. W. RANSON 
When arising from the ganglion or from the sympathetic trunk, 
it follows very closely the course of the branch to the superior 
thyroid artery as far as the origin of that artery, and then turns 
laterally to end as stated above. It is undoubtedly identical 
with the branch which Langley says constantly arises as one of 
the two terminal divisions of a nerve from the lower pole which 
runs downward along the truncus sympathicus and common 
carotid artery, the other terminal division being directed along 
the superior thyroid artery (see branch to superior thyroid artery). 
As table 1 shows, the branches from the superior cervical 
ganglion running to the cervical nerves contain relatively few 
myelinated fibers. Some of these contained none, and for such 
branches the area was not computed. In no ease did a branch 
going entirely or in part to the third cervical nerve contain any 
myelinated fibers, but in view of the wide variations in the 
number of such fibers contained in the other branches it is 
doubtful if this is of any significance. The largest number, 
44, was found in the branch to the first cervical nerve in Cat | 
IV. The number per square millimeter in this branch varied 
from 7447 to 251 in the several cats. A study of the table 
makes it apparent that there is no regularity in the distribution 
of the myelinated fibers nor in the relative proportion of myelin- 
ated and unmyelinated fibers. If any particular functional group 
were myelinated one would expect more regularity both in the 
relative and absolute number of these fibers than is apparent in 
the table. The great majority of these fibers did not exceed 
3.3u in diameter. In some of the branches larger fibers were 
present, and in one case 50 per cent had a diameter of 6.6u 
or greater. Are these larger fibers of the same character as the 
smaller ones, or are we dealing here with an occasional admixture 
of fibers of another category? ‘These larger fibers, for example, 
might be sensory and be directed toward the superior cervical 
ganglion. Are the small myelinated fibers preganglionic and 
coming from the cervical nerves, or postganglionic and taking 
their origin in the superior cervical ganglion? These questions 
can best be discussed after the other branches from the ganglion 
have been studied. The table is instructive, however, in showing 
