INTRODUCTION". 45 



Diseases are spoken of as comvuaiicable and non-communicable. 

 The communicable are divided into two classed — the specific, as 

 glanders and small-pox, and the septic, as erysipelas. Communica- 

 ble diseases are those that have existed in an animal body before. 



The non-communicable diseases are caused by morbific agents 

 which do not come from an animal body, but have their origin in 

 a place or thing, as malarial fever, yellow fever in the human sub- 

 ject. 



Contagion spreads how ? 



Principally by absolute contact with the poison, by inoculation, 

 by food or water, through excreta, by stable utensils, etc. 



Define a sporadic disease. 



It is one that occurs in isolated cases — that is, where a disease 

 of an infectious or contagious nature manifests itself in one animal. 



What is an enzootic disease ? 



This term comes from the Greek en, " in," and zoon, " an 

 animal." 



It is where a number of cases occur in a limited locality, due 

 to the same cause. 



Define an epizootic disease. 



It comes from epi, " upon," and zoon, " an animal." It is a 

 disease that is widely spread over a community. 



What terms in human medicine describe similar con- 

 ditions ? 



The terms endemic and epidemic. 



Define a panzootic disease. 



This is a disease that is infectious or contagious, and spreads 

 from one country to another. 



What is a zymotic disease ? 



This is a disease of a contagious nature, but produced by the 

 action of a ferment. 



