FEBVES, SKIN, AND EYE, 



803 



Fig. 1055.— Lock |aw. { 



When idiopathic, it is probably due to changes of temperature, 

 exposure to cold and wet when the skin is heated, or the presence of 

 irritants inthe stomach and intestines. Any irritation of the nerv- 

 ous system may produce it. When traumatic, it is due to wounds 

 or bruises. 



Symptotks. — The first 

 thing usually noticed is a 

 disinclination to feed, and 

 a straddling gait, due to 

 stiffness in the hind legs. 

 (See Fig. 1055.) An ex- 

 amination of the mouth 

 shows that the jaws can- 

 not be opened. Soon the 

 muscles become rigid, 

 the muzzle is extended, and the tail is slightly straightened. Some- 

 times the contortions of the body are very severe. When the 

 back is arched downward, as in Fjg. 1056, and the head cannot 

 be lowered, the form is termed Ophisthotonos. 



Fig. 1056.— Ophisthotonos. 



Fig. 1057.— Emprosthotonos. 

 ll 



Fig. 1058. — Pleurosthotonos. 



