22 LIFE AND DEATH. 



spot must be irremediable, and must necessarily cause 

 death. But if the vital knot be destroyed, and 

 respiration be artificially induced by means of a 

 bellows, the animal resists: it continues to live. It is 

 only the nervous stimulating mechanism of the 

 respiratory movements which has been attacked in 

 one of its essential parts. 



Life, therefore, resides no more in this point than it 

 does in the blood or in the stomach. Later experi- 

 ment has shown that it resides everywhere, that each 

 organ enjoys an independent life. Each part of the 

 body is, to use Bordeu's strong expression, "a« animal 

 in an animal"; or to adopt the phrase due to Bichat, 

 ^' a particular machine withiti the general machine." 



The Vital Tripod. — What then is life, or, in other 

 words, what is the biological activity of the individual, 

 of the animal, of man ? It is clearly the sum total, or 

 rather, the harmony of these partial lives of the 

 different organs. But in this harmony it seems that 

 there are certain instruments which dominate and 

 sustain the others. There are some whose integrity 

 is more necessary to the preservation of existence and 

 health, and of which any lesion makes death more 

 inevitable. They are the lungs, the heart, and the 

 brain. Death always ensues, said the early doctors, if 

 any one of these three organs be injured. Life 

 depends, therefore, on them, as if upon a three-legged 

 support. Hence the idea of the vital tripod. It is no 

 longer a single seat for the vital principle, but a kind 

 of throne on three-supports. Life is decentralized. 



This was only the first step, very soon followed by 

 many others, in the direction of vital decentralization. 

 Experiment showed, in fact, that every organ separated 

 from the body will continue to live if provide'd with 



