INTRODUCTION. 49 



What symptoms are furnished by the extremities and 

 the surface of the body ? 



Normally, these have a warm, genial sensation to the sense of 

 feel, and variations of the temperature of these in disease are of 

 major importance. 



In inflammatory processes the ears, the legs, and the surface 

 of the body may be cold — may be deathly cold, as it is termed. 



If they keep cold for a length of time, it is an indication of 

 trouble of a grave nature. 



If there is also present what is called a " cold sweat," the life 

 is in danger. 



DIAGNOSIS. 



What is understood by the term diagnosis? 



This is a branch of general pathology, and comes from the 

 Greek dia, meaning " through," and gignosko, meaning " I know " 

 — I know through, or a looking through, or a thorough knowledge. 



It is the art of discriminating one disease from another, or 

 the discovery of disease by means of its symptoms. 



What use is diagnosis? 



We make a diagnosis in order to enable us to prognose, and 

 also to treat the various diseases. 



What is understood by a direct diagnosis? 



It is a diagnosis made when the morbid condition is revealed 

 by a combination of clinical signs, or some one or more pathog- 

 nostic symptoms. 



What is a differential diagnosis ? 



It is the art of discovering the disease which is present by a 

 careful comparison of its symptoms with those of other diseases 

 which may closely resemble it. 



What is understood by a diagnosis by exclusion ? 



It is the proving of the absence of all diseases which might 

 give rise to the symptoms observed, except one. In other words, 

 it is a negative proof. 



PROGNOSIS. 



What is understood by a prognosis ? 



This is another division of general pathology, and comes from 

 the Greek pro, " before," and gignosko, meaning " I know " — " I 



