DICTIONARY OF THE VETERINARY ART. 261 



present, are ultimately and surely pernicious. The true plan 

 is to give antispasmodics. (See Antispasmodics.) 



Nares. The nostrils. 



Necrosis. The mortification and separation of a portion 

 of dead bone from the other parts of the bone. 



Nephrotics. Medicines that act on the kidneys. 



Nerves. We have already observed that the brain consists 

 of two portions : one large, called cerebrum, and one small, 

 called cerebellum. There are three pairs, or columns, of 

 nervous matter proceeding from the brain, through the back 

 bone, or spinal column : these disperse themselves into 

 branches and twigs, and are distributed over the system. 



By a great number and variety of experiments upon living 

 animals, Dr. Bell and others have proved beyond dispute, that 

 the nerves of the anterior (towards the belly) columns are 

 distributed to all the voluntary muscles, and designed to pro- 

 duce voluntary motion ; that those of the posterior, or 

 towards the back, are distributed to all the sensative tissues, 

 and designed to convey to the brain all the impressions 

 derived from the presence of external objects. These two 

 arrangements are styled the nervous system of external rela- 

 tion. By similar experiments it was discovered that the two 

 lateral or side columns of nervous matter are distributed to 

 the muscles concerned in the act of respiration. 



Lastly, seated principally among the thoracic and ab- 

 dominal viscera, there are large quantities of nervous matter, 

 having only slight connection with the sensative and mo- 

 tive nerves. This system has many knotty appearances, from 

 the union and distribution of its fibres ; these are again dis- 

 tributed to different parts. These are called plexuses, and the 

 whole structure is called the sympathetic nerve. It is some- 

 times named the nerves of nutrition. 



Dr. Curtis observes, " It has long been a subject of inquiry 

 what is the modus operandi of nervous action. Some have 

 supposed that the nerves are solid cords that vibrate, like the 

 strings of musical instruments; others, that they are sheaths 

 containing a subtile fluid, that darts through them as electricity 



