144 THE HUMAN BODY. 



4, Each of these masses is in two halves, which are 

 precisely alike. The two halves of the cerebrum and cere- 

 bellum are partly separate. The two halves of the pons 

 and the medulla are united. 



5, The surface of the cerebrum and cerebellum, instead 

 of being smooth, is divided into ridges, with furrows be- 

 tween them. These ridges are called the convolutions of 



Fig. 54. 



HALF OP THE BRAIN, AND UPPER END OF THE SPINAL CORD, WITH THE NERVES 

 COMING FROM THEM. 1. Cerebrum. 2. Cerebellum. 3. Pons Varolii. 4. Medulla 

 oblongata. 5. The Eyeball. 



the brain. One great difference between the brain of man 

 and of the lower animals is, that it has more of these 

 convolutions. Very intelligent animals have more of 

 them than animals less intelligent. 



6, The medulla oblongata is the lowest portion of the 

 brain. It is just above the great opening in the base of 

 the skull. Through that opening, it is continuous with 

 the spinal cord. 



