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HUMAN PHYSIOLOGY 



The Sympathetic Nervous System. — The sympathetic nervous system 

 consists of a series of ganglia connected with each other and with the cen- 

 tral nervous system through some of the spinal and cranial nerves, especially 

 the vagus (tenth cranial). The sympathetic system, both in the frog and 

 man, controls the muscles of the digestive tract and blood vessels, the 

 secretion of gland cells and all functions which have to do with life processes 

 in the body. 



Functions of the Cerebrum. — In general, the functions of the 

 different parts of the brain in man agree with those functions 

 we have already observed in the frog. T'he cerebrum has to do 

 with conscious activity, that is, thought. It presides over what 

 we call our thoughts, our will, and our sensations. Each part 

 of the area of the outer layer of the cerebrum is given over 

 to some one of the different functions of speech, hearing, 

 sight, touch, movements of bodily parts. The movement of 

 the smallest part of the body has its definite localized center in 

 the cerebrum. Experiments have been performed on monkeys, 



