Course. Diagnosis. 643 



Course. In the majority of cases the disease lasts only a 

 few days, usually two to five, and in many cases death occurs 

 in even a shorter time, while in rare cases the animal may sur- 

 vive for weeks or even months. 



In cases in which the disturbance of consciousness sets in 

 rapidly and in severe form there are frequently focal symptoms 

 also. Both the general and local symptoms increase in severity 

 as the inflammation extends and the local symptoms may also 

 increase in number and their distribution may become more ex- 

 tensive. In such cases death is not long delayed. The general 

 cerebral symptoms and the local symptoms may decrease, or, 

 except in the early stages, disappear. Such a course indicates 

 disease either of the crura or the cerebellum. Obviously such 

 symptoms may cause death in a short time owing to some seri- 

 ous complication or to some portion of the brain essential to 

 life becoming involved. In the few animals that recover there 

 is a tendency to relapses, and according to Dexler this is espe- 

 cially the case in animals that have had hemorrhagic inflamma- 

 tion in the neighborhood of the lateral ventricles. In such cases 

 there is a great likelihood of the recurrence of attacks of mania 

 and staggers. 



Even if a relapse does not occur the animals, as a rule, 

 show permanent sensory disturbances. Evidence of the occur- 

 rence of such cases of encephalitis should be found more fre- 

 quently, and especially in horses that have suffered from stag- 

 gers and at the postmortem of which nothing can be found to 

 account for the staggers. In dogs and in other animals there 

 may persist a tendency to epileptiform fits. In rare cases there 

 are persistent local symptoms which depreciate the value of the 

 animals. There is no doubt that in certain cases of encepha- 

 litis there is complete recovery and this possibly explains the 

 complete disappearance of the severe symptoms observed in 

 some animals affected with distemper or' influenza. 



In the sub-acute forms there is, as a rule, a gradual loss of 

 consciousness, and the cases terminate fatally owing to the fact 

 that the animals take little nourishment. In the liorse there 

 may be relapses of the inflammation from time to time. 



Diagnosis. If general, and what is of more importance, 

 local symptoms of one of the diseases mentioned in the para- 

 graph devoted to etiology are present, and there is no pain of 

 the cranium, diagnosis is easy. In dogs encephalitis due to dis- 

 temper may be diagnosed^ if there are rhythmic spasms of the 

 same groups of muscles. "In cases that appear to be uncompli- 

 cated the appearauce of cerebral symptoms associated with a 

 rise of temperature, acceleration of pulse, and absence of pain 

 over the cranium, raises the suspicion that they are simple cases 

 of encephalitis; suppurative encephalitis is excluded if no pri- 

 mary suppuration can be found in any part of the body and no 

 injury to the cranium can be found. The disease is easily con- 



