200 EQUINE PHYSIOLOGY. 



Sylvius and at the junction of the anterior with the middle third 

 of the surface. The upper part presides over the hinder extrem- 

 ity of the opposite side, the middle over the anterior extremity, 

 and the lower over the face. In front of the latter in man is 

 found the speech centre on the left side. 



The centre for sight is located in the occipital region ; those for 

 smell, hearing and taste in the temporo-sphenoidal region. 



THE SYMPATHETIC SYSTEM. 



This chain of twenty-eight ganglia is sensible after long stimu- 

 lation. 



After section of the cord in the neck, there is increased vascu- 

 larity by paralyzing the coats of the small vessels. 



Functions. — It influences the general process of nutrition 

 and forms the vasomotor system. This sends branches to 

 small blood-vessels, and influences local circulation by vaso-dila- 

 tors and vaso-contractors. 



SPECIAL SENSES. 



TOUCH. 



When a foreign body is brought into cont.ict with the surface, 

 it is appreciated by the nerves of the part as the special sense of 

 touch. 



This sense is located in the skin and al>o on mucous mem- 

 branes for a certain distance. The termination of nerves in the 

 skin has been already noticed. In the hor^.e, with a single digit 

 covered with hard material, the hoof is an imperfect organ of 

 touch, but can estimate solidity and resistance. 



The hp is a well-marked tactile organ, the end bulbs of Krause 

 being very abundant. 



SMELL. 



The sense of smell is very acute in the horse. It has already 

 been sufficiently considered under the anatomical description. 



TASTE. 



Taste enables the animal to detect the flavor of substances. 

 The anterior two-thirds of the tongue preside over the abihty to 

 recognize acids and alkalies, and is supphed by the chorda tym- 



