THE CELL AND PROTOPLASM. 135 



definite chemical compound. No such compound 

 has been discovered, 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 

 reduce life to any simpler basis than this com- 

 bination 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 

 then asked whether these fundamental properties 

 were themselves those of a chemical compound or 

 whether they were to be reduced to the action of 

 still smaller machines. The first answer which 

 biologists gave to this question was that assimila- 

 tion, growth, and reproduction were the simple 

 properties of a complex chemical compound. This 

 answer was certainly incorrect. Life activities 

 are exhibited by no chemical compound, but, so 

 far as we know, only by the machine called the 

 cell. Thus it is that we are again reduced to 

 the problem of understanding the action of a 

 machine. 



It may be well to pause here a moment to 

 notice that this position very greatly increases 



