260 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



39), where the fibres from and to the brachial segment 

 of the cord of a dog enter the cortex, contractions of 



certain muscles of the fore- 

 leg must follow. If we 

 stimulate the region A (Fig. 

 39), which is connected with 

 the sensory or motor ganglia 

 of the eyes, motions of the 

 latter must be produced. It 

 is, moreover, evident that if 

 we injure the spot D in the 

 cortex we must get some- 

 what different after-effects 

 from those produced when 

 A is injured. In the former 

 case we must expect motor 

 disturbances in the use of 



FIG. 39. CEREBRAL HEMISPHERES t h e fore-leg, in the latter dis- 

 OF A DOG. , ^ , . . 



A, optical region; D, brachial region; tUrbattCCS Of V1S1OH. 

 G, region of the hind-leg. (After Jj- J f COUrSC, HOt tO 



Munk.) 



be expected that the distri- 

 bution of segmental fibres on the cortex follows min- 

 utely the arrangement of the ganglia in the spinal 

 cord. Displacements of elements occur in the cerebral 

 hemispheres during the process of growth. This is 

 indicated by the formation of folds formed on the 

 surface. It is possible that not all the segmental 

 ganglia send fibres directly to the hemispheres, and it 

 is possible that certain ganglia are connected with the 

 cortex at more than one spot or region. From the 



