102 Termination of Disease. 



oxygen and output of carbon dioxide, it is essential to accept as 

 causes of death of primary importance, various lesions and func- 

 tional disturbances of the hind brain, the heart and the lungs. 

 These parts are therefore spoken of as the atria mortis. Inhibi- 

 tion of their functions may be a direct result of chemical, me- 

 chanical or electrical influences (as from poisons which destroy 

 or paralyze the nerve cells, concussion, the action of lightening), 

 or may indirectly follow a wide variety of factors interfering 

 with tissue nutrition, metabolism and gaseous interchange (anse- 

 mia, albuminous waste, closure of respiratory passages, elevation 

 or depression of body-temperature, reflex palsies). The more 

 important modes, therefore, by which this or that disease may 

 induce death, are : 



1. Cessation of cardiac action, caused by toxic or reflex nerv- 

 ous paralysis of the cardiac ganglia, fatigue and degeneration of 

 the cardiac muscle, cardiac rupture, complete obstruction to the 

 escape of blood from the cardiac chambers (formerly known as 

 e.ritus lethalis per syncopeni, (tw-koitthv, to strike together). 



2. Asphyxiation, from interference with intrapulmonary 

 respiratory interchange of gases, obstruction of the lungs or upper 

 respiratory passages, compression of these tubes, spasm or palsy 

 of the respiratory muscles, diaphragmatic rupture (exitus lethalis 

 per suffocationem). 



3. Mednllary Paralysis, or paralysis of the respiratory centre 

 in the medulla oblongata, from circulatory interference at the 

 base of the brain, influence of toxic substances upon the nerve 

 cells, concussion of the brain or reflex influences (exitns lethalis 

 per apoplexiain, d-n-owXricraei.i', to strike down). 



4. Hceniorrhage, from rupture of important vessels, or ex- 

 travasation of large amounts of blood into the somatic and 

 visceral cavities. 



5. Exhaustion, from inanition or consumption (diminished 

 nutrition and exaggerated metabolism, accumulation of fatigue 

 products and poisonous metabolites, auto-intoxication). 



These modes of death may, of course, complicate each other 

 and may be mutually causative of each other (as when haemor- 

 rhage induces ischsemia of the heart and coronary vessels, with 

 the result of cardiac cessation and at the same time the symptoms 

 of suffocation, due to an anaemia of the medulla). Senile debility, 

 more or less complicated by various diseases, is also to be re- 

 garded as a cause of death (senile marasmus, from ^apaiveiv, to 



