568 KEKVOUS DISEASES. 



a considerable time without moving his jaws. If the animal's legs 

 be placed in a constrained position, he will maintain it, although 

 it would be extremely irksome to him Avere he in health. " A sign 

 which is very characteristic, is dragging the fore legs on the ground 

 when the horse is made to rein back. This is not done by animals 

 which make a difficulty in reining back on account of want of 

 training, or pain in the loins " (Trasbot). The expression and 

 actions are those of stupidity and insensibility to external impres- 

 sions. Sometimes the disease assumes an acutely inflammatory 

 course, which is accompanied by symptoms of excitement and deli- 

 rium. 



TREATMENT, which may consist of strong purgatives (aloes or 

 Epsom salts) and iodide of potassium, is rarely of any use. 



Paralysis of the Face. 



The nerves (the seventh pair) which, on each side of the head, 

 supply the muscles of the lips, nostrils, cheeks, eyelids, and ears 

 with power of movement, on leaving the brain, issue respectively 

 tlirough the canal of the internal ear, and gain the outside of 

 the cheek just below the point of the jaw (Fig. 115, p. 299). They 

 pass, one on each side, along the cheek, close under the skin, to 

 the lips; giving off, during this course, branches to their various 

 muscles. 



SYMPTOMS. — Drooping of the eyelid, inability to fully close the 

 eye, powerlessness to erect the ear, and difficulty of breathing, 

 owing to impairment of the respiratory organs in the throat or 

 chest, are signs of the injury to the nerve being more deeply 

 placed than its point of passage below the joint of the jaw. 

 These nerves communicate with nerves (the tenth pair) which 

 largely influence the action of breathing and of the heart. 

 Difficulty of breathing may be also caused, especially during 

 work, by falling in of the nostrils, owing to the muscles which 

 dilate their opening, being paralysed. If the muscles only of 

 the lips, nostrils and cheek be implicated, we may conclude 

 that the seat of injury is on the superficial course of the nerve. 

 As they are motor nerves (their action being to stimulate muscular 

 contraction) ; arrest of their function through injuiy, will be 

 followed by a continued flaccid condition of the muscles which they 

 supply. The paralysis may be on one side or on both. When 

 the nerve on one side only is affected, the lip will be drawn 

 away from that side, owing to the paralysed muscles not being 

 able to oppose the action of those of the healthy side. If both 



