THE CERVICAL SYMPATHETIC TRUNK 5 US 
turn about the cells, and wherever several are grouped together 
they run parallel to each other in small compact bundles. They 
do not give in any way the appearance of the intercellular 
network. 
By way of summary we may say that the fine myelinated fibers 
entering the ganglion through the sympathetic trunk are pre- 
ganglionic elements and form by their ramifications a compli- 
cated intercellular plexus of fine unmyelinated fibers. The 
other branches of the ganglion consists of many unmyelinated 
and a few myelinated fibers. These all represent the axons of 
Fig. 12 Three cells from the ganglion cervicale superius of a dog in which 
the sympathetic trunk had been cut 58 days before the dog was killed. The fine 
fibers of the intercellular plexus are absent. Pyridine silver. 800. 
the cells in the ganglion and take no part in the formation of 
the intercellular plexus. They are the postganglionic fibers of 
Langley. 
SYNAPSES IN THE SUPERIOR CERVICAL GANGLION 
Where are the synapses on the paths through the superior cervica 
ganglion located? Langley (00), using his method of paralyzing 
the endings of preganglionic fibers by nicotine, has shown that 
the fibers of the sympathetic trunk, destined for the superior 
cervical ganglion, come from the upper thoracic white rami and 
run without interruption through the upper thoracic ganglia. 
