62 PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



cells of the cerebrum. From these battery cells there 

 go wires, converging to the hallway and forming there 

 a great cable of wires going out of the door ; these are 

 the white fibers converging and forming the medulla, and 

 going out of the skull as the cord. Before going out, 

 however, certain wires are sent out from the cable to 

 all the offices in the building; these are the cranial 

 nerves going to the head and face, and especially to the 

 sense organs. The cable starts out now to communi- 

 cate with the whole country, but protected by an arch- 

 way ; this is the cord protected by the vertebral column. 

 As it goes, the cable gives out wires to adjacent and 

 even distant regions; these are the spinal nerves. These 

 must go to every State, county, and city, and terminate 

 in intelligence offices and in executive or police offices; 

 these are the sense organs and the muscles. Suppose 

 also the alcoves are all named as States and the bat- 

 teries all numbered. 



Now, suppose anything to occur in any place. The 

 intelligence office reports the fact to the head center. 

 The State, county, city, neighborhood, is at once known, 

 and the command immediately goes out to the execu- 

 tive office and determines appropriate action. 



Application. — Let us now apply this idea and show 

 how it explains the phenomena: 



i. Cut the cord high up in the neck. The whole body 

 is paralyzed to both consciousness and volition, but not 

 to reflex function, for that is in the gray matter of the 

 cord, which we are not now considering. Prick the foot 

 and it will jerk, but the prick is unfelt and the jerk is in- 

 voluntary. Meanwhile all the parts of the face are unpar- 

 alyzed. The patient sees and speaks as usual, because 

 the nerves controlling these come out from the medulla. 



2. Cut the cord in the middle of the back. Now the 

 upper parts of the body, including the arms, etc., feel 



