INTRODUCTION. 17 



Death by COma commences at the brain. The sym- 

 ptoms present are, firstly, those due to deficiency of cere- 

 bral energy, loss of sensation and power of voluntary 

 motion, stupor, with slow stertorous breathing, and later 

 the medulla becomes involved, and the respiratory centre 

 ceases to perform its function, and the right side of the 

 heart becomes blocked up with dark blood. Apoplexy 

 causes death in this way. Prolonged artificial respiration 

 may enable the medulla to regain its energy, as when 

 coma results from certain poisons. 



Our prognosis requires especially diagnosis of the patho- 

 logical conditions of the diseased parts, and makes a 

 knowledge of morbid anatomy, sometimes termed intimate 

 PATHOLOGY, a matter of the highest moment. The ana- 

 tomical changes which occur in organs during the progress 

 of disease vary according to the structure of the parts and 

 to the nature of the diseased action. The objects of 

 morbid anatomy are to determine exactly the changes 

 which structures undergo as a result of diseased processes, 

 how those changes are related to each other, how their 

 Causes have operated to produce them, and how they are 

 liable to affect the wellbeing of the animal. The methods 

 of morbid anatomy comprise examination of all organs, 

 tissues, and elements which have been altered by disease. 

 These parts may be procured in many cases from the living 

 animal, but in others only on post-mortem examination. 

 They require to be subjected to all available processes, 

 physical, chemical, microscopical, — indeed, the study of 

 morbid anatomy is but a branch of diagnosis — the exten- 

 sion of its methods as above enumerated. Our determi- 

 nations of the changes which have occurred in an organ 

 are only made in some cases after death, and the infor- 

 mation thus gained must be applied at an earlier stage of 

 future cases. The changes which structures undergo 

 during disease may be in situation, structure, form, and 

 size ; also it seems that in some cases their function may 

 be changed either by increase, decrease, or perversion 

 without appreciable alteration in structural characters. 

 Displacement of elements, tissues, and organs results in 



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