592 



General Symptomatology of Diseases of the Brain. 



from the point of view of diagnosis is far more important, is shown by the move- 

 ments of the animal resembling those of an intoxicated person; staggering for- 

 wards, backwards, or sideways, and finally falling, and there may be swaying 

 movements of the head. The animal appears to be trying to balance itself (figs. 

 80 and 81). During progression the feet are raised up high, in some cases abducted 

 and in others adductod, advanced with a swinging motion and set down heavily. 

 The animal cannot take food or water because the swaying movements of the head 

 in all directions upset any vessel containing food. When the muscles have no equili- 

 brating function to carry out, as for example when the animal is at rest and in 

 many of the movements carried out when the animal is lying down, the symptoms of 

 loss ' of equilibrium which before were pronounced apparently disappear entirely. 

 If the movements are more closely observed even a minimal disturbance of co- 

 ordination may be noticed. 



Bilateral disease of the vestibular nerve may cause symptoms exactly resembling 

 those of cerebellar ataxia. This has been observed in a fowl in which suppuration 

 of the petrous temporal bone extending to the labyrinth resulted from bilateral 

 purulent otitis. In this case the brain was quite free from lesions. 



The convulsions which occur in some cases of disease of the 

 motor areas of the cortex constitute the socalled cortical or 

 Jacksonian epilepsy. In this condition there are tonic-clonic 



Fig. 80. Dog aflected with cerebellar Fig. 81. Dog affected with cerebellar 



ataxia. ataxia. 



(Illustrations made from two photographs, one taken immediately after the other.) 



spasms of the whole body at long and variable intervals which 

 may be accompanied by slight loss of sensibility over a cir- 

 cumscribed area. This loss of sensibility may be absent. The 

 spasms always start in the same group of muscles and gradu- 

 ally spread to neighboring muscles or to the whole body. The 

 lesion is situated in that part of the motor area containing the 

 center controlling the group of muscles in which the spasms 

 start. In a case of staggers we were able to satisfy ourselves 

 that exceptionally a local sjanptom may become an epileptiform 

 attack associated with coma and involving the whole body, espe- 

 cially when the attack always begins in the same group of 

 muscles. 



Spasms occur in the areas supplied by the cranial nerves 

 when the lesions are near the nucleus or nerve root. For exam- 



