DISEASES OF THE NERVOUS SYSTEM. 319 



co-ordinated functional activity of the neuro - muscular 

 mechanism — i. e., of the nerve-centers, nerves, and mus- 

 cles. In a fit or convulsion this is not the case; the 

 movements are irregular, purposeless, and generally ai-e 

 injurious, and always wasteful of the energies of the 

 animal. 



Epilej>tiform convulsions are due to an irregular dis- 

 charge of the nerve-cells, which are in a highly unstable 

 condition ; they are independent of the will, occur during 

 unconsciousness, are not dependent on a stimulus from 

 without, but usually on no stimulus that we are able to 

 trace, or else upon some tumor, etc., of the brain. 



They occur unexpectedly, last a variable period, the 

 spasms are usually either of the nature of one prolonged 

 muscular contraction {tonic), or from the first or following 

 on the other variety they consist of alternate contraction 

 and relaxation {clonic). The dog usually froths at the 

 mouth, and may bite the tongue. Epilepsy may be heredi- 

 tary, or due to injuries to the head which have resulted 

 from severe concussion, new growths, to the irritation of 

 worms, etc., though it is better to speak of the disturbance 

 in such cases as convulsions which may be epileptiform in 

 character and reflex, as they certainly are when due to 

 teething and worms. 



Fits, then, may arise from teething, from worms, indi- 

 gestion, and a variety of causes, such as exhausting dis- 

 eases, nursing puppies to the point of debility, or the virus 

 of certain diseases, as distemper. 



Treatment— Dm'mg the fit nothing can usually be 

 done but to prevent the animal injuring himself as far as 

 possible, and from escaping when deranged mentally. If 



