MOLECULAR STEUCTURE AND LIFE PICTET. 211 



In this case it is a momentary death, understand, and destined to 

 be followed after more or le&s delay by a resurrection which brings 

 back into circulation the temporarily inert atoms. It is clear, in 

 fact, that if all cyclised molecules should indeJBnitely persist in that 

 state all life would soon disappear from the surface of our globe, 

 but then all that I have said applies only to organic compounds 

 which form part of the living plant. When a plant dies other 

 agents intervene which proceed more or less rapidly to the destruc- 

 tion of all the molecules and to a general decyclisation. The dead 

 plant forthwith becomes a prize of the microbes of putrefaction, 

 which attack its albumens, and of the oxydizing ferments which 

 bura its cellulose. Or we may substitute the digestive ferments of 

 herbiverous animals, which are equally cyclolitic. Here, as else- 

 where, the vegetable and animal kingdoms are complements one of 

 the other and interdependent, and these same atoms, passing from 

 one to the other in the aggregate of diverse structures, sustain the 

 eternal existence of both. 



Such are the considerations that I proposed to submit to you on 

 the relations existing between molecular structure and life. I have 

 raised only a small corner of the veil that hides the m3'^stery, but 

 I believe I have answered the three questions with which I began, 

 by showing: (1) That the phenomena of life are dependent upon 

 a special structure of the organic molecule; (2) that only the dis- 

 position of atoms in open chains permits the maintenance and the 

 fhanifestations of life; (3) that the cyclic structure is that of the 

 substances which have lost this faculty; and (4) finally that death 

 results, from the chemical point of view, by a cyclisation of the 

 elements of the protoplasm. The serpent which bites its tail, the 

 symbol of eternity among the ancients, might well become, to the 

 modern biological chemist, the symbol of death. 



I have spoken only of plant chemistry. It remains to examine 

 whether my interpretation can apply likewise to the phenomena 

 which take place in the animal organism. But I can not, nor do 

 I wish to, longer tax your patience, for I have already taken too 

 long a time in testing it. 



