176 LIFE AND DEATH. 



a great affinity for oxygen. It absorbs it so greedily 

 that the gas cannot remain in a free state in its 

 neighbourhood. Living protoplasm, therefore, exer- 

 cises a reducing power. But it does not absorb 

 oxygen in this way for its own advantage ; oxygen 

 is not absorbed, as was supposed thirty years ago, to 

 supply fuel wherewith to burn the protoplasm. The 

 products are not those of its oxidation, of its own 

 disintegration. They are the products of combustion 

 of the reserve-stuff which is incorporated in it. 

 These substances have been supplied to it from 

 without, like the oxygen itself, with the blood. This 

 was proved by G. Pfltiger in 1872 to 1876. The 

 protoplasm is only the focus, the scene, or the 

 factor of combustion. It is not its victim, it does 

 not itself furnish the fuel. It works like the chemist, 

 who obtains a reaction with the substances that are 

 given to him. 



As for the reducing power of protoplasm, A. 

 Gautier in 1881 and Ehrlich in 1890 have given fresh 

 proofs. A. Gautier in particular has insisted that the 

 phenomena of combustion take place, so to speak, 

 outside the cell, and at the expense of the products 

 which surround it ; while on the contrary the really 

 active and living parts of the nucleus and of the 

 cellular body, work protected by the oxygen, as in the 

 case of anaerobic microbes. 



This result is of great importance. Burdon Sander- 

 son, the late learned professor of physiology at the 

 University of Oxford, has not hesitated to compare 

 it to the discovery of respiratory combustion by 

 Lavoisier. There is no doubt some exaggeration in 

 the comparison ; but there is, on the other hand, no 

 less exaggeration in supposing that it is not of great 



