322 S. W. RANSON AND P. R. BILLINGSLEY 
carotid nerve remains unchanged and contains as many myelin- 
ated fibers as the nerve of the opposite side. Measurements 
show that fibers of all sizes from 1.5 to 7u are present, showing 
that there has not occurred a dropping out of the fibers of a 
particular size. In fact, figure 3 represents an internal carotid 
nerve after the complete degeneration of the sympathetic trunk 
below the superior cervical ganglion of the same side, but illus- 
trates perfectly well the normal structure of the nerve. 
Fig. 3 From asection of the nervus caroticus internus in the cat. Osmic acid. 
x 425. 
One must also consider the possibility of these myelinated 
fibers being contributed through the rami connecting the superior 
cervical ganglion with the upper cervical and certain of the cranial 
nerves. Against this assumption are the observations that can 
be made on serial sections through the superior cervical ganglion 
and ‘the internal carotid nerve after degeneration of the trunk. 
