4 Introduction. 



ing or induration of the liver), occupation of spaces and formation 

 of false membranes by fibrinous material (pleurisy, croup), micro- 

 scopic changes in the cells (karyolysis, fatty infiltration). 

 (2) Chemico-pathological processes: Quantitative and qualitative 

 changes of the chemical constituents of the animal organism and its 

 parts (metabolic faults), as the presence of bile in the blood, albu- 

 men in the urine, uric acid in the joints or abnormal proportion of 

 water in the blood. [Here might well be included, too, the ex- 

 cessive formation or uric acid or its salts, of the faulty carbohy- 

 drate changes of diabetes, the development of faulty types of 

 albumen in the blood and within the cells, the toxic changes of 

 uraemia and other intoxications, those essentially chemical processes 

 which underlie in an important degree the changes produced by 

 infections, as well as a wide group of more or less indefinite meta- 

 bolic diseases.] 



(3) Functional-pathological or symptomatic disturbances (some- 

 times spoken of as dynamic disturbances) : These are faults in the 

 nicety of balance of the various physiological activities of the or- 

 ganism, as the occurrence of convulsions, pain, unconsciousness, 

 labored breathing, diarrhoea or dribbling urine. Functional dis- 

 turbances are usually caused by structural and metabolic faults. 

 Commonly the latter are primary, as in physiological life the effi- 

 ciency, growth and development of the organs are dependent upon 

 the chemical processes of nutrition and metabolism. Our knowl- 

 edge of the morphological and chemical basis of functional de- 

 rangements is, however, incomplete. 



Consideration, description and investigation of pathological 

 variations may therefore be divided into (a) Pathological Morphology 

 or Anatomy, (b) Pathological Chemistry and (c) Symptomatology, 

 together with (d) considerations of the influences under which dis- 

 eases develop, and the actual causes of disease (Aetiology: ahia, 

 cause). In the origin of disease some cause is apt to act so as to 

 bring about material changes, chemical and physical, patholo^^ical 

 lesions {Iced ere, to injure) of the component elements and organs, 

 as well as the counteraction or pathological reaction on the part 

 of these same elements and organs, both of which manifest them- 

 selves by functional disturbances (symptoms or signs of disease). 



That phase of pathology which seeks to explain the development 

 of lesions and symptoms constitutes Pathogenesis (7; yheais, de- 

 velopment, beginning) ; that which concerns the observation of 

 the chronological succession of disease-events, the onset, course 



