THE CELL AND PROTOPLASM. 115 



and liquids, each of which has its own chemical 

 composition. The number of chemical compounds 

 existing in the material formerly called protoplasm 

 no one knows, but we do know that they are many, 

 and that the different substances are combined to 

 form a physical structure. Which of these various 

 bodies shall we continue to call protoplasm ? 

 Shall it be the linin, or the liquids, or the micro- 

 somes, or the chromatin threads, or the centro- 

 somes ? Which of these is the actual physical 

 basis of life ? From the description of cell life 

 which we have given, it will be evident that no 

 one of them is a material upon which our chemi- 

 cal biologists can longer found a chemical theory 

 of life. That chemical theory /)f life, as we have 

 seen, was founded upon the conception that the 

 primitive life substance is a definite chemical 

 compound. No such compound has been dis- 

 covered, and these disclosures of the microscope 

 of the last few years have been such as to lead 

 us to abandon hope of ever discovering such a 

 compound. It is apparently impossible to re- 

 duce life to any simpler basis than this combi- 

 nation of bodies which make up what was for- 

 merly called protoplasm. The term protoplasm 

 is still in use with different meanings as used by 

 different writers. Sometimes it is used to refer to 

 the entire contents of the cell ; sometimes to the 

 cell substance only outside the nucleus. Plainly, 

 it is not the protoplasm of earlier years. 



With this conclusion one of our fundamental 

 questions has been answered. We found in our 

 first chapter that the general activities of animals 

 and plants are easily reduced to the action of a 

 machine, provided we had the fundamental vital 

 powers residing in the parts of that machine. We 



