ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 719 



2. Pupillo-dilator to the Gasserian ganglion, in the ophthalmic 

 branch and long ciliary nerves to dilator fibers of the iris. 



3. Motor to Miiller's smooth muscle of the orbit and Tenon's 

 capsule. 



4. Secretory to sweat-glands. 



If you irritate the cervical portion of the sympathetic, the eye- 

 ball is projected by a contraction of the smooth, muscular fibers of 

 the capsule of Tenon; the pupil dilated. The recti muscles push 

 the eyeball inward. The vasomotor nerves, constrictors, and dila- 

 tors are in the cervical sympathetic, and when it is irritated the 

 blood-vessels of the ear, conjunctiva, iris, tongue, epiglottis, and 

 palate are contracted, whilst we have a dilatation of the vessels of the 

 retina, lips, gums, and nasal mucous membrane. 



The cervical sympathetic also acts upon the circulation of the 

 brain and that of the thyroid gland. 



Thorax. The fibers of the thoracic organs arise from the five 

 upper dorsal nerves, go out through the first thoracic ganglion, then 

 go through the annulus of Vieussens to the inferior cervical ganglion, 

 and pass to the heart and lungs, as the cardio-accelerator and the 

 vasoconstrictors of the lungs. 



Abdomen. These fibers come off from the lower six dorsal and 

 upper three lumbar nerves. The great splanchnic nerve is formed 

 by branches from the fifth to the tenth thoracic ganglia, and termi- 

 nates in the semilunar ganglion of the solar plexus and in the 

 superior mesenteric plexus. 



The lesser splanchnic is formed by filaments from the tenth to 

 eleventh thoracic ganglia, and goes to the solar and renal plexus. 

 The splanchnic nerves are the greatest vasoconstrictor nerves in the 

 body, and contain inhibitory fibers of the small intestines. They also 

 contain motor fibers to the intestines. 



Pelvis. The fibers for the pelvis emerge from the cord by the 

 lower dorsal and upper four lumbar nerves, and have their cell-sta- 

 tion in the inferior mesenteric ganglia, from which they run in the 

 hypogastric nerves to the pelvic ganglia. They contain vasoconstric- 

 tors, inhibit the colon, give motor-power to the bladder, uterus, and 

 vagina. 



The mesenteric nerves go to the superior mesenteric ganglion, 

 and then to the hypogastric plexus. The coeliac, the superior mesen- 

 teric, and the hypogastric prevertebral ganglia are united amongst 

 themselves by connections parallel to the sympathetic chain. These 

 ganglia form in some sort a second chain anterior to that which fol- 



