244 THEORY AND PRACTICE 



it is called Orthotonos. When the masseter muscles are af- 

 fected it is called Trismus. Both forms are common. The 

 tetanus germ must be associated with other germs in order to 

 set up its infection ; it cannot work alone. 



Semeiology. — The symptoms are clearly diagnostic usually. 

 The 'first thing you will notice is a contraction of the masseter 

 muscles. The muscles will be drawn around the mouth. The 

 animal seems to have difficulty in eating and he secretes an enor- 

 mous amount of saliva. After a few hours he becomes excitable, 

 the nose is extended, the facial muscles twitch and any little dis- 

 turbance excites the animal. The eyeballs are retracted in the 

 orbit and look small. The membrana nictitans is hable to be 

 raised constantly over more or less of the eyeball, and when the 

 head is raised will cover it. An intelligent horseman will no- 

 tice the beginning stiffness of gait. Trismus is usually well 

 marked; after twenty- four or forty-eight hours the development 

 seems to be quite gradual, other times violent, in which case the 

 animal will soon die. The spasms which Vvcre at first in the 

 masseters finally affect the whole body. The dorsal, cervical and 

 gluteal muscles are the most affected. The tail is elevated and 

 it maintains that position and trembles. The respiration is ac- 

 celerated and the nostrils are dilated ; the ears stand like sticks, 

 the limbs are stiff and are straddled ; locomotion is very difficult ; 

 flanks are tucked up ; ribs are tightly drawn, due to contraction 

 of the intercostals. As the pain becomes intense, the animal 

 sweats profusely and is very excitable. The spasms come on 

 from time to time and between times the muscles relax a little, 

 but not enough to cause much hope. The action is spasmodic. 

 During a spasm the gluteal muscles often shoot out behind like 

 a eoose in flig^ht, and the action throws the animal to the floor 

 and he cannot rise until the muscles relax. An animal usually 

 does not rise after going down on account of the stiffness of the 

 legs ; he is unable to get them under him enough to get up. The 

 recumbent position and being unable to rise increase the fre- 

 quency and severity of the spasms. The spasms are easily 

 brought on, — a rat or loud talking or the presence of a stranger 

 may be the cause. The saliva is ropy, the pulse grows hard ; the 



