CHAPTER 11. 

 PATHOLOGY. 



Pathology, or more properly, when applied to the lower animals, 

 Zoo-Pathology, is derived from the Greek words JlaOog, a 

 disease, and Aoyo9, a discourse — the doctrine of disease ; and 

 is divided into Geneeal and Special Pathology. 



General Pathology includes — 1st. Etiology, or a knowledge 

 of the causes of disease : 2d. Semiology or Symptomatology, or 

 a knowledge of the morbid phenomena or symptoms by which 

 disease is manifested : Sd. Pathogeny, which deals with the 

 seats or localities of disease : 4th. Nosology — its division and 

 classification : 5th. Diagnosis — the methods by which it is 

 detected — its distinction : 6th. Prognosis — its probable results ; 

 and Morbid Anatomy, including Histology — the method by 

 which the morbid alterations of structure and the elementary 

 constituents of diseased products are discovered. 



Etiology. — The causes of disease, or, in other words, the cir- 

 cumstances which precede it, and to which its occurrence is due, 

 are arranged under three heads, namely — the 2^^'^disjposing, the 

 exciting, and the proximate. 



The term proximate is used to represent the pathological con- 

 dition or essential bodily change on which the symptoms of 

 disease depend ; in fact, the proximate cause has been stated 

 to be the disease itself, and for this reason some writers have 

 expunged the term, and have been content to arrange the causes 

 of disease under the heads predisposing and exciting. Later 

 writers, however, have revived the term, and Dr. Bristowe gives 

 the following illustration : " A woman who has been frequently 

 exposed to the contagion of scarlet fever without taking the 

 disease, becomes at the period of childbirth again exposed, and 

 now suffers from a virulent attack. Here, parturition (which, 



