68 General Biology 



2. The optic nerves, running from the optic lobes, crossing each 

 other to form the optic chiasma and passing to the eye on the opposite 

 side of the head. 



3. The Oculomotor, supplying the muscles of the eye. 



4. The Trochlearis ( ), sometimes called the 

 patheticus, supplying the muscles of the eye. 



5. The Trigeminus ( ), or trifacial, a sensory 

 nerve, supplying the sides of the head. 



6. The Abducens ( ), supplying the muscles 

 of the eye. 



7. The Facial, chiefly motor in its action and supplying the sides 

 of the head. 



8. The Auditory, supplying the inner ear. 



9. The Glossopharyngeal ( ), a sensory nerve, 

 supplying the pharynx and tongue. 



10. The Pneumogastric ( ), or vagus, supplying 



the larynx, heart, and stomach. 



THE SYMPATHETIC SYSTEM 



The main trunks of this system consist of a nervous strand on each 

 side of the spinal column (Fig. 337). Throughout the abdominal cavity 

 one may see the chain of minute nerve ganglia, ten in number, which are 

 also connected with the spinal nerves. From these chains of ganglia 

 tiny nerves are given off, supplying the intestine, the kidney, and other 

 abdominal organs. 



Although the sympathetic system is connected with the spinal 

 nerves, it has entirely distinct and separate functions. Microscopically, 

 one finds quantities of neurones, each with its little cell-body, dendrites, 

 ( ) and axon. These are massed in the brain and 



cord, as well as in the ganglia outside of the cord. Some of them carry 

 impulses to the center and some away from it. There are several 

 branches where a vast intermingling of the sympathetic strands is seen, 

 the principal ones being called the coeliac, ( ) or 



solar plexus, supplying the stomach, intestine, liver, pancreas, spleen, 

 and sending fibers to the gonads and kidneys, and the urogenital plexus, 

 supplying kidneys and gonads primarily. 



THE SENSE ORGANS 



If one marks a series of spaces on the volar ( ) 



surface of the fore arm of a human being about a millimeter square, and 



