DIGESTIVE APPARATUS. 143 



In h o r s e s the following changes are observed : 



1. In inflammatory swelling of lips and cheeks as well 

 as in paralysis of the cheeks (facial or ?th nerve), horses 

 take up their food with their teeth and experience difficulty 

 in getting it into the mouth. 



?. In cerebral depression they show similar peculiari- 

 ties ; while drinking they may insert the nostrils below the 

 level of the water and "masticate" it. 



3. In tetanus feeding is very laborious ; mastication and 

 suction movements are impossible because the spasmodic con- 

 traction of the masseter muscles has closed the buccal cavity. 



In cattle normal feeding is disturbed in inflammatory 

 affections of the tongue (actinomycosis), this organ often 

 bei oming hard and rigid (woody tongue). Cattle thus 

 affected grab their food like dogs. 



The manner of drinking water must also be 

 observed. Normally only dogs and cats lap their drink. 

 When the facial nerve is paralyzed animals must insert the 

 whole mouth into the water so that they can get it near 

 enough to the pharynx to swallow it. 



c. Mastication. The briskness with which this act is 

 performed bears a direct relation to the palatability of the 

 food and the appetite of the animals ; healthy horses and cat- 

 tle make 60-100 masticatory movements per minute. 



Masticatory movements are conspicuously retarded in 

 cerebral depression, in the course of severe fevers, and in 

 acute and chronic hydrocephalus. The animals cease masti- 

 cating for some time, seem "absent minded," and forget to 

 eat. This often happens while the mouth is full of feed, and 

 pieces of hay and straw sticking out of it. 



Mastication is made difficult in paralysis of the facial 

 nerve; here the food collects in large masses in the lower 

 part of the mouth; it is also observed in tetanus or spasms 

 of the masticatory muscles due to other causes. 



Mastication is impaired and laborious when mechanical 



