THE VITAL PHENOMENA OF BACTERIA. 51 



of life," oxygen is taken from chemical com- 

 pounds which, in consequence, suffer disinte- 

 gration and rearrangement of their parts. 

 Pasteur observed this phenomenon of anaero- 

 biosis first in fermentations, thereby renewing 

 acquaintance with a process previously known 

 to some alchemists, and described as a " fer- 

 mentatio clausal It is really a question of 

 the decomposition of very unstable bodies, a 

 process resulting from the disturbing influ- 

 ence of molecular movements imparted to 

 these bodies by the substances exciting fer- 

 mentation. 



In the chemical building-up of the body- 

 substance of living things we can distinguish 

 several groups of phenomena : polymerization, 

 a sort of doubling up of a simpler compound ; 

 synthesis, a union of different kinds of simple 

 compounds into one more complex substance ; 

 formation of anhydride, by which new sub- 

 stances arise from a compound through the 

 loss of water ; and reduction or loss of oxygen, 

 which is brought about especially by the 

 entrance of hydrogen into the molecule. The 

 breaking down of organic bodies in and through 

 the action of living things takes place through 

 the loosening of the bonds of polymeriza- 

 tion ; through hydration or entrance of water 

 into the molecule ; and through oxidation. 



