420 



THE NEBVOUS SYSTEM 



development of a function the larger and, more prominent 

 the area has been proved false. 



Third. The interconnection of areas has been shown 

 to be so intimate that, although normally specific areas 

 control specific functions, an injury to one part may affect 

 all the others. 



In other words, the cerebrum is composed of many 

 organs intimately associated with one another and inter- 

 dependent. In general, the left hemisphere controls the 



Vision ;„ -^^ 



Fig. 197 — Diagrams illustrating localization of functions in the cerebrum; /, outer 

 surface of left hemisphere; II, inner surface of same. Motor areas are shaded; 

 Cc, corpus callosum; Fr, frontal lohe; Oc, occipital lohe; Pa, parietal lobe; ito, 

 fissure of Rolando; ^y, Sylvian fissure; fTCi temporal lobe. 



right side of the body and vice versa. The chief motor and 

 sensory areas of the hemispheres are shown in Figure 197. 

 Fiinctions of the medulla. — This is the center of those 

 reflexes which control the respiratory and circulatory 

 organs. When a cut is made anterior to the medulla 

 the animal continues to breathe and the heart to beat 

 for some time after the operation. If, however, the cut 

 is made at the point where the medulla joins the cord or 

 it is destroyed entirely, heart beat and breathing soon 

 cease and rapid death foUows. Other important reflexes 



