532 
PHYSIOLOGY: S. J. MELTZER 
Proc. N. a. S. 
ARE THE SUPERIOR CERVICAL GANLIA INDISPENSABLE TO 
THE MAINTENANCE OF LIFE} 
By S. J. MkIvTzkr 
Rockefeller Institute for Medical Research 
Read before the Academy, April 26, 1920 
The sympathetic nerve fibres which originate in the thoracic part of 
the spinal cord terminate in the superior cervical ganglia, from which 
separate bundles of nerve fibres go to the various parts of the head. Ex- 
periments with stimulation of the central end of the cervical sympathetic 
nerves revealed that these nerve fibres control various functions localized 
in the head. For instance, to mention the more important ones, the 
contraction and dilatation of the bloodvessels of various parts of the head, 
the constriction and dilatation of the iris and the secretion of various glands. 
Section of the sympathetic nerve showed that some of these innervations are 
in a state of tonus, for instance, the pupils become constricted and the 
bloodvessels of the ear (to be seen best in rabbits) become dilated. By 
means of local application of nicotine to the ganglia which paralyzes 
postganglionic but does not affect preganglionic nerve fibres, Langley has 
shown that some of the postganglionic nerve fibres of the superior cer- 
vical ganglia are simply a continuation of the cervical sympathetic, pre- 
ganglionic nerve fibres, while other postganglionic nerve fibres have their 
origin in nerve cells within the superior cervical ganglia. 
About sixteen years ago we^ showed that epinephrin (adrenalin) which, 
if administered by subcutaneous injection, or by instillation in the con- 
junctival sac, in normal animals, shows no influence upon the size of the 
pupil, produces promptly a dilatation of the pupil and a considerable reduc- 
tion of its responsiveness to light, if the subcutaneous injection or the 
instillation were made in animals in which the corresponding ganglion 
was removed. To obtain this result the subcutaneous injection or instil- 
lation must be made about twenty-four hours in rabbits and forty-eight 
hours in cats and dogs after the removal of the ganglion. Cutting of 
the cervical sympathetic nerves has no such effect. These facts were 
best illustrated in an experiment in which the superior cervical ganglion 
was removed on one side and the sympathetic nerve was cut on the other 
side. A simultaneous instillation of adrenalin in both conjunctival sacs 
caused a dilatation of the pupil on the side in which the ganglion was 
removed, but not on the side in which merely the sympathetic nerve was 
cut. For that reason we designated this pupilary phenomenon as "para- 
doxical." These experiments revealed that in the normal state, and for 
twenty-four hours in rabbits, or for forty-eight hours in cats and dogs, 
after the removal of the superior cervical ganglion, the normal condition 
of the pupil is maintained by influences which take their origin in nerve 
cells within the superior cervical ganglion and not in the spinal cord. 
