358 MANUAL OF EQUINE MEDICINE. 



rough, and staring. The bowels are irregular ; sometimes 

 constipated, sometimes loose. 



In most instances a peculiar blue line is observed on the 

 gums where the teeth are implanted ; but in the parts be- 

 tween the teeth this line is not present. This symptom is 

 mostly regarded as diagnostic, but sometimes it appears to • 

 be very faint or absent. 



Roaring is a symptom generally present, and is probably 

 to be attributed to a paralytic condition of the nerves supply- 

 ing certain muscles of the larynx {vide ' Roaring '). The 

 muscles often twitch and contract spasmodically. 



Difficulty of locomotion and paralysis, especially of the 

 hind-limbs, are also liable to become developed in chronic 

 poisoning by lead. 



Sometimes the joints become swollen and the flexor 

 muscles of the fore-limbs contracted, probably from paralysis 

 of the extensor muscles of the limbs. 



The animal thus appears to stand on its toes, and when 

 it walks, it seems to knuckle over on the fetlocks. 



The paralysed muscles may undergo atrophic and 

 degenerative changes. 



Diagnosis. — Acute lead poisoning may be mistaken for 

 gastric and enteric disorders, accompanied with paralytic 

 symptoms. 



In lead poisoning, however, the muscular twitchings and 

 fits are more frequent and more distinctive. The tucked 

 up condition of the abdomen, the discharge of saliva, and 

 the grinding of the teeth are also features indicative of 

 poisoning by this substance. 



In the chronic form of poisoning, which may be mistaken 

 for articular rheumatism of a severe type, the paralytic 

 features, the irregular recurrence of muscular twitchings 

 and spasmodic contractions, as well as the ' blue line ' when 

 formed, are sufficiently indicative. 



