SYMPTOMS 189 



of the dilator of the upper lip, give an abnormal shape to the 

 opening of the mouth. The muscles of the tongue, of degluti- 

 tion and of the larynx are also usually attacked by spasms. 



(3). The extensor muscles of the neck. Contraction ol 

 these muscles cause a stiff, stretched out carriage of the head 

 and " ewe neck." The muscles of the neck become hard and 

 tense to the touch. 



(4). The extensor muscles of the back. Spasms of these 

 muscles are manifested by an extremely hard condition of the 

 muscles of the back, loins and croup. Several conditions may 

 arise. Orthotonvis in which the neck is stretched out and the 

 back and croup are carried horizontally or, opisthotonus in 

 which the head is raised and drawn back and the vertebral 

 column slightly depressed. This is the most common occur- 

 rence. There may be a lateral curvature of the cervical 

 vertebrae which is uncommon and also a convex curvature of 

 the vertebrae which is very rarely observed. The tail, espe- 

 cially in horses, is often raised and occasionally said to be 

 straight with the back. 



(5J. The muscles of the limbs. The spasms in these 

 muscles make the limbs stiff and cause the animal to assume 

 an attitude in which the fore legs are extended forward and 

 laterally and the hind ones backward and laterally. They are 

 bent at the joints onh- with difhculty. The contraction of the 

 muscles of the abdomen gives the animal a tucked up appear- 

 ance and the spasms of the muscles of respiration render 

 breathing difficult. 



Besides the spasms the animal shows an increased reflex 

 irritability and heightened sensibility. These manifest them- 

 selves in excitement, timidity and intensified muscular con- 

 tractions if irritated. Sweating is common especially in severe 

 cases. In mild cases it may be absent. There is usually 

 little or no change in the internal temperature. In fatal cases 

 the temperature is usualh' constantly high toward the last. 

 The high temperature (104° to 106° F) usually continues for 

 some time after death. Bayer has observed in a horse, 24 

 hours before death, a temperature of 102° F ; one and a half 

 hours before death, 105° F ; at the moment of death, 111° F ; 



