666 



Gid. 



The following are some of the forced movements observed: 



Movements in circles, the circles varying in size. As a rule, the 

 diameter of the circles decrease in size until tinally the animal goes 

 round and round on a very small space, and then loses its balance and 

 falls down. Exceptionally, the circles described remain the same size 

 for a. long time, and even get larger, until the animal finally stands 

 still. 



Rotation movements. In these the animal rotates alwut one fore 

 or hind foot as a fixed point with the head and neck dropped. 



When animals press forwards the head is in most cases sunk do^^^l 

 on the breast, and the legs are lifted high ; but exceptionally, the head 

 is bent over backwards and the animals stumble and fall down. 



In animals that fall backwards, the head is bent backwards; and 

 there are tonic spasms of the muscles of the neck. 



Rolling is only rarely observed and lasts only for a short time. 



Falling on the side is somewhat more frequently seen. (For the 

 diagnostic importance of these movements, see page 670.) 



In many cases only certain groups of muscles are involved 

 in tlio toiiio-clonir spasms (Jacksonian epilepsy), but in others 



they liegin in the same 

 group of muscles, but ex- 

 tend to the rest of the body. 

 In the somewhat more 

 advanced cases, there may 

 be appreciable yielding on 

 pressure of the roof of the 

 cranium, and it is usually 

 over the frontal or parietal 

 bone that this can be felt. 

 If there is a complete re- 

 moval of bony tissue from 

 the place, there is actual 

 fluctuation. Pressure on 

 such places sometimes 

 causes the animal to col- 

 lapse, or there may be mus- 

 cular spasms or epilepti- 

 form seizures. The soft area does not always mark the position 

 of the cyst, for, as Hutyra & Marek have shown it may be found 

 on the opposite side (fig. 92). Percussion of the area not rarely 

 gives a more hollow sound than the surrounding parts that have 

 not undergone a process of thinning. 



In the final stage of the disease, the animals are very ema- 

 ciated and lie motionless on the ground, respond to no stimuli, 

 take neither food nor water, and finally die, the respiration 

 having become of the Cheyne-Stokes type. 



In cattle the onset of the disease is marked by loss of appe- 

 tite, dullness, gradually progressive giddiness, and blankness 

 of expression. The neck may be extended or even rigid. There 

 is a tendency to collapse, the head may be supported upon the 

 manger, held obliquely or it may show pendulum movements. 



Fiff. 94. Gid. 



