864 DEATH. 



to fix an exact time at which we say the body is dead. We can, however, 

 fix no such exact time to the death of the individual tissues. They are not 

 mechanisms, and their death is a gradual loss of power. In the case of the 

 contractile tissues, we have apparently in rigor mortis a fixed term by 

 which we can mark the exact time of their death. If we admit that after 

 onset of rigor mortis recovery of irritability is impossible, then a rigid 

 muscle is one permanently dead. In the case of the other tissues we have 

 no such objective sign, since the rigor mortis of simple protoplasm manifests 

 itself chiefly by obscure chemical signs. And in all cases it is obvious that 

 the possibility of recovery, depending as it does on the skill and knowledge 

 of the experimenter, is a wholly artificial sign of death. Yet we can draw 

 no other sharp line between the seemingly dead tissue whose life has flickered 

 down into a smouldering ember which can still be fanned back again into 

 flame, and the handful of dust, the aggregate of chemical substances into 

 which the decomposing tissue finally crumbles. 



Moreover, the failure of the heart itself is at bottom loss of irritability, 

 and the possibility of recovery here also rests, as far as is known at present, 

 on the skill and knowledge of those who attempt to recover. So that, after 

 all, the signs of the death of the whole body are as artificial as those of the 

 death of the constituent tissues. 



