458 FUNCTIONAL NERVOUS DISEASES 



short duration, from two to ten minutes. The time elaps- 

 ing between the attacks is variable. The prodromal symp- 

 toms are anxiety, staring expression, increased respiratory 

 movements, and sometimes slight twitching of the muscles. 

 When occurring in pigeons the number affected should be 

 noted to determine whether or not an infectious disease is 

 causing it. 



Diagnosis. A differential diagnosis should be made be- 

 tween vertigo and epilepsy. The main differential feature 

 is the absence of convulsions in vertigo. The symptom 

 vertigo is not so difficult to determine, but its causes may 

 remain quite obscure. 



Prognosis. Should not be considered very favorable as the 

 cause is hard to determine. Individual attacks of the dis- 

 ease usually do not cause any serious disturbance barring 

 accidents and injuries. 



Treatment. During an attack of vertigo the animal should 

 be placed in a comfortable, quiet place and protected from 

 injury. Following the attack the examination should be 

 directed to find out the underlying cause and treatment 

 applied accordingly. When the condition occurs in pigeons 

 as a contagious disease, the entire premises should be dis- 

 infected after the removal of all affected birds. Individual 

 treatment in these cases is unsatisfactory. 



EPILEPSY. 



Definition. Epilepsy is a disease of the central nervous 

 system which is characterized by convulsions occurring at 

 irregular intervals, the subject usually being unconscious 

 during the attack. 



Etiology. The cause of primary true epilepsy is unknown 

 although it is regarded as being hereditary; at least the 

 offspring of epileptic parents are markedly predisposed to 

 the disease. This has been observed in man as well as in the 

 domesticated animals. 



Pathology. No postmortem lesions of any kind have 

 been observed either in animals or man which would account 

 for the disease. 



Symptoms. In epilepsy the attacks come on suddenly, 

 the. animal performing uncontrollable movements. This is 



