THE CELL AND PROTOPLASM. 149 



of comprehending the life phenomena in our 

 chemical and mechanical laws. 



But have we thus reduced these fundamental 

 phenomena to an intelligible explanation? It 

 must be acknowledged that we have not. We 

 have reduced them to the action of chemical 

 forces acting in a machine. But the machine 

 itself is unintelligible. The organic cell is no 

 more intelligible to us than is the body as a 

 whole. The chemical understanding which we 

 thought we had a few years ago in protoplasm 

 has failed us, and nothing has taken its place. 

 We have no conception of what may be the 

 primitive life substance. All we can say is 

 that this most marvellous of all natural pheno- 

 mena occurs only within that peculiar piece of 

 machinery which we call the cell, and that it is 

 the result of the action of physical forces in that 

 machine. How the machine acts, or even the 

 structure of the machine, we are as far from 

 understanding as we were fifty years ago. The 

 solution has retreated before us even faster than 

 we have advanced toward it. 



SUMMARY. 



We may now notice in a brief summary 

 the position which we have reached. In our 

 attempt to explain the living organism on the 

 principle of the machine, we are very successful 

 so far as secondary problems are concerned. 

 Digestion, circulation, respiration, and motion 

 are readily solved upon chemical and mechanical 

 principles. Even the phenomena of the nervous 



