C. Comparative Pathology and Pathological 



Anatomy. 



As human characteristics are illustrated by a comparison 

 between the behaviour of men and that of animals so the 

 pathological side of the question, as well as the anatomical and 

 physiological, must be treated by distinguishing general and 

 special processes. 



By comparative researches of this kind we can determine 

 which pathological changes, both of external and internal 

 origin, are common to man and other animals, and which 

 others are proper to man alone. 



I. General Pathology and Pathological Anatomy. 



Comparative pathology and histology teach us that the 

 foundation of all animal bodies, including man's, is the cell from 

 which the primitive tissues are developed, aggregations of which 

 go to form the different organs and parts of the body. 



Comparative physiology further teaches that the chemical 

 composition of similar cells, tissues and organs in all animals, 

 including man, is practically identical, and that what we know 

 as life is manifested as a chemico-physical process in the cells. 



Further, since disease is only life under altered conditions, 

 consisting of deviations from the average as regards shape, re- 

 lationship or activity, human and animal pathology must be 

 regarded as essentially a cellular process, and the remarkable 

 changes which take place in the diseased cells, tissues or organs 

 must be admitted to be, to all intents and purposes, the same 

 both in man and in animals. Pathologically, this correspond- 

 ence between the two is first noted when we consider the causes 

 of disease. 



The animal body is directly damaged by anything which 



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