CHAPTER X. 



Nervous system. Cerebro-spinal nervous centre. Cerebrum. Cere- 

 bellum. Isthmus of the encephalon. Medulla oblongata. Spinal cord. 

 Membranes; dura mater, arachnoid, pia mater. Nerves; cranial 

 nerves, spinal nerves, great sympathetic. Functions of the nervous 

 system; functions of the spinal nerves of motion and of sensation; func- 

 tion of the cranial nerves; functions of the spinal marrow. functions 

 of the encephalon ; medulla oblongata, pons Varolii, peduncles of the 

 cerebrum and cerebellum, corpora quadrigemina, pineal gland, optic 

 thalami, cerebrum and cerebellum. Functions of the great sympathetic. 

 Reflex pouter. Nerve force. Memory. 



/ The nervoiis system comprises the cerebrum and cerebellum, 

 ( the spinal cord, and the nerves. It is divided into two por- 

 tions, the one central, and the other external or peripheric. 

 The first has received the name of the cerebro-spinal nervous 

 centre, because it is constituted by the organs which form the 



, encephalon and by the spinal cord. The second is the whole 

 of the nerves proper. Starting from the nervous centre, of 

 which they are the expansion, they are distributed to the 

 whole body. They transmit motive or functional impulses 

 from the nervous centre to every part of the organism; and 

 the impressions of sensibility from the periphery, that is to 

 say from the different points of the body to the nervous 

 centre. 



The cerebro-spinal nervous centre appears in the form of a 

 soft pulpy symmetrical trunk. Its upper portion is an oval 

 enlargement contained within the cranium, and is called 

 ths encephalon or brain. The lower portion is elongated 

 on leaving the cranium in the form of a spindle it is the 

 spinal marrow, and is contained in the vertebral canal. 

 Brain. This is the term commonly applied to all the 



