Human Physiology. 

 CHAPTER II. 



BRAIN AND NERVES. 



The Brain Form and Structure The Ganglionic Nervous System Mode 

 of Nervous Action Complexity and Mystery Origin of Nerves 

 The Brain the Organ of the Mind Has each Faculty of the Mind a 

 distinct Organ? 



THE brain of man does not differ much in appearance from the 

 brains of other animals. You have a soft substance, with little 

 more consistence than cream ; white in its interior, and gray, 

 or ash colour, on the exterior. It is held in place by delicate 

 membranes, and the surface is increased by convolutions, as 

 shown in Fig. 18. The brain is a double symmetrical organ, 

 each portion on one side of the head having its counterpart on 

 the other, so that injury or paralysis of one side does not 

 necessarily suspend its functions. 



The best idea of the general structure of the human brain is 

 given by a longitudinal section through its centre as shown in 

 Fig. 27. The upper and whiter portion is the cerebrum, 21 



FIG. 27 LONGITUDINAL SECTION OF THE BRAIN. 



Inner surface of left hemisphere and divided cerebellum, showing the 



arbor vitse. 



