The Nervous System. 95 



course of some nerves are enlargements termed ganglia. 

 The nerve ends take the form of loops or bulbs according 

 to their locality, e. g., as loops in muscles, as bulbs in 

 mucous membranes. A nerve fibre retains its individu- 

 ality its entire length, if a nerve is cut across the ends do 

 not unite or grow together, the part away from its source 

 of nutrition dies. 



A. The Brain. The large portion of the brain is known 

 as the cerebrum; this portion is the seat of the intellect. 

 The faculties of reason and memory are derived from 

 the cerebrum. This part of the brain is located under- 

 neath the forehead. From the base of the brain originate 

 the twelve pairs of cranial nerves, some of which go to 

 supply sensation to the ear, eye, tongue, nose, etc. The 

 cerebellum is an organ with the power of co-ordinating 

 muscular movement, that is to say, it controls the mus- 

 cular parts, moves them in the right direction and at 

 the right time. For example, the crossing of the limbs 

 when walking by the intoxicated person shows lack of 

 co-ordination. 



The Pons connects the various other parts of the brain, 

 some of the fibres going to make up the cranial nerves 

 originate here. The Medulla oblongata may be consid- 

 ered as a prolongation of the spinal cord, it forms a 

 pathway for nerve impulses to and from the brain, gives 

 origin to some of the cranial nerves, and contains the 

 centers or headquarters to which the nerves governing 

 the heart, lungs, circulation and part of the digestive 

 tract bring messages and receive orders, thus the nerve 

 centers controlling mastication, swallowing, sucking, 

 vomiting, breathing, coughing, secreting saliva, and the 



