MODES OF DEATH. 121 



SO effective and so useful in balancing the circulation and in 

 restoring the passage of blood through the lungs as the applica- 

 tion of heat to the whole body, frictions, stimulating applications 

 to the extremities, warm clothing, and bandages, in addition to 

 abundance of pure air for the animal to breathe, and that blood- 

 letting frequently affords apparent relief. 



DEATH BEGIXNING AT THE BEAIN. 



Death by coma, or beginning at the brain, is much less com- 

 monly witnessed in the lower animals than death by apncea or 

 by asthenia. Such diseases, however, as parturient and idiopathic 

 apoplexy, cerebral meningitis, and other allied affections, which 

 act upon and destroy the functions of the brain, cause death in 

 this w^ay. Death by coma is also induced by certain narcotic 

 poisons, such as opium, as well as by inordinate quantities of 

 effete materials in the blood, more especially urea and carbonic 

 acid ; by fractures of the cranial walls, the pressure of tumours, 

 abscesses, serum or extravasated blood, and by coagula in the 

 cerebral arteries, obstructing the flow of blood, and causing 

 anaemia of the cerebral mass. 



The symptoms of coma are stupor, insensibility, suspension of 

 voluntary motion, wliich come on sometimes suddenly, as in 

 apoplexy and injuries of the head, whilst in other cases they 

 supervene gradually. The breathing becomes slow, irregular, 

 stertorous ; the instinctive motion of breathing still continues, 

 but all voluntary attention to the act is lost. The feeling of the 

 want of air is still sufficiently strong and powerful to excite, 

 through the medium of the pneumo-gastric and branches of the 

 fifth nerves, the reflex power of the medulla oblongata to sustain 

 the involuntary movements of the thorax ; but at length this 

 fails also, the chest ceases to expand, the blood is no longer 

 aerated, and thenceforward precisely the same internal changes 

 occur as in death by apnoea. — (Watson.) 



Coma ultimately destroys life in the same way as apnoea, 

 with this difference, that in death by apnoea the aeration of the 

 blood and the functions of the lungs cease first — the circulation 

 of the non-arterialized blood destroying the functions of the 

 brain ; whilst in coma the functions of the brain cease first, and 

 in consequence of the loss of nervous power, the movements of 



