NERVOUS SYSTEM. 



211 



interest in their surroundings, do not recognize familiar per- 

 sons, run against obstacles, etc. In feeding they grab the food 

 with the incisor teeth, chew slowly and "languidly," stop 

 without a motive when food is still in the mouth and between 

 the lips. In drinking they plunge their mouth into the water 

 and often ''chew" it. It is hard to make them move, they 

 step around clumsily, won't "get over" when commanded to 



Fig. 51. 



Horse "with chronic hydrocephalus. 



do so ; they are hard to guide when driven, try to stay over 

 on one side ; if badly affected they cannot be used for serv- 

 ice because they do not recognize commands. According to 

 the degree of mental depression we recognize : 



Dullness; 



Somnolency, sleepiness, drowsiness, from which the pa- 

 tient is easily roused. 



Sopor, profound sleep, rousing difficult. 



Coma, complete insensibility. 



A dulling of the psychic functions occurs in ; 



