34 PRACTICE OF EQUINE MEDICINE. 



What is meant by aetiology ? 



It is that division of general jjnt^iologt/ that treats of the cause 

 of disease ; or, it is the condition under wliich disease arises, or the 

 agents through which disease is produced. 



How may causes be divided ? 



We may divide causes into predisposing and exciting; they may 

 also be divided into internal and external. 



What are predisposing causes ? 



They are certain influences or conditions of the animal body 

 which disposes it to the action of disease by the application of some 

 exciting factor, and may be inherited or acquired. 



Define exciting causes. 



Exciting causes are those circumstances and agents which may 

 excite disease by operating on an already predisposed body. 



What is included under internal or intrinsic causes ? 



Internal or endopathic causes include heredity, age, pi'cvioics 

 disease, dreed or variety, temperame?it, idiosyncrasy, or diathesis. 



The external or exopathic causes include what ? 



External or extrinsic causes include atmospheric influences, 

 temperature (extreme heat or cold), faulty diet, luorJc, defective 

 sanitary conditions, mechanical causes. 



Define semiology or symptomatology. 



Symptoms are the language of diseased nature ; symptoms and 

 signs are such alterations in the healthy functions as give evidence 

 of the existence of a diseased condition or perverted function. 



Why do we study symptoms ? 



We study symptoms to enable us to make a diagnosis or pi'og- 

 nosis, and to be able to treat. 



Symptoms are how divided ? 



Symptoms may be divided into objective and subjective. 



Define each. 



Symptoms are said to be objective when evident to the senses of 

 the observer ; subjective, when felt and complained of by the patient. 



Symptoms are also general or local, idiopathic or sympathetic 

 (secondary), premonitory (precursory) or commemorative. 



