subsequent attacks of the same, or a different disease. An individual may
suffer from an attack of pneumonia that so weakens the disease-resisting
powers of the lungs as to result in a tubercular infection of these organs.
In the horse, one attack of azoturia predisposes it to a second attack. One
attack of an infectious disease usually confers immunity against that
particular disease. _Heredity_ does not play as important a part in the
development of diseases in domestic animals as in the human race. A certain
family may inherit a predisposition to disease through the faulty or
insufficient development of an organ or group of organs. The different
species of animals are affected by diseases peculiar to that particular
species. The horse is the only species that is affected with azoturia.
Glanders affects solipeds, while black leg is a disease peculiar to cattle.


QUESTIONS

1. What is disease?

2. How are diseases classified? Give an example of the different classes.

3. What is a predisposing cause? Exciting cause?

4. Name the different predisposing and exciting causes of disease.




CHAPTER II

DIAGNOSIS AND SYMPTOMS OF DISEASE