326 LIFE AND DEATH. 



disease, by accident, or of old age. And as disease 

 is an accident, we may naturally ask if what we call 

 old age is not also a disease. 



However that may be, the mortal process, being 

 never instantaneous, has a duration, a beginning, a 

 development, an end — in a word, a history. It 

 constitutes an intermediary phase between perfect 

 life and certain death. 



Necrobiosis. Atrophy. Degeneration. — The process 

 according to the circumstances may be shortened or 

 prolonged. When death is the result of violence 

 events are precipitated. The physical and chemical 

 transformations of the living matter constitute a kind 

 of acute alteration called by Schultze and Virchow 

 necrobiosis. According to the pathologists, there are 

 two kinds of necrobiosis : — that by destruction, by 

 simple atrophy, which causes the anatomical elements 

 to disappear gradually without undergoing appreci- 

 able modifications ; and necrobiosis by degeneration, 

 which transforms the protoplasm into fatty matter 

 into calcareous matter, into granulations (fatty de- 

 generation, calcification, granulous degeneration). 

 There is no disagreement as to the causes of this 

 necrobiosis. They are always accidental ; they ' 

 originate in external circumstances: — the insufficiency 

 of the alimentary materials, of water, of oxygen ; the 

 presence in the medium of real poisons destroying 

 the organized matter ; the violent intervention of 

 physical agents, heat, electricity ; the reflex on the 

 composition of the cellular atmosphere of a violent 

 attack on some essential organ, the heart, the lungs, 

 the kidneys. 



Senescence. Old Age. — In a second category we 

 must place the mortal processes, slow in their move- 



