2OO 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-dilators and vaso- 

 contr actors. 



SPECIAL SENSES. 



TOUCH. 



When a foreign body is brought into contact 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 also on mucous membranes 

 for a certain distance. The termination of nerves in the skin has 

 been already noticed. In the horse, with a single digit covered 

 with hard material, the hoof is an imperfect organ of touch, but 

 can estimate solidity and resistance. 



The lip 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 ability to 

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



