THE LIVING MACHINE BUILDING FACTORS. 185 



at first seemed to be a homogeneous body, and 

 was looked upon as a chemical compound of 

 high complexity. If this were true its properties 

 would depend upon its composition and would be 

 explained by the action of chemical forces. Such 

 a conception would have quickly solved the prob- 

 lem, for it would reduce living properties to 

 chemical powers. But the conception proved to 

 be delusive. Protoplasm, at least the simplest 

 form known to possess the fundamental life prop- 

 erties, soon showed itself to be no chemical com- 

 pound, but a machine of wonderful intricacy. 



The fundamental phenomena of life and of 

 protoplasm have proved to be both chemical and 

 mechanical. Metabolism is the result of the 

 oxidation of food, and motion is an instance of 

 transference of force. Our problem then re- 

 solved itself into finding the power that guides 

 the action of these natural forces. Food will 

 not undergo such an oxidation except in the 

 presence of protoplasm, nor will the phenomena of 

 metabolism occur except in the presence of living 

 protoplasm. Clearly, then, the living protoplasm 

 contains within itself the power of guiding this 

 play of chemical force in such a way as to give 

 rise to vital phenomena, and our search must be 

 not for chemical force but for this guiding prin- 

 ciple. Our study of protoplasm has told us 

 clearly enough that we must find this guiding 

 principle in the interaction of the machinery 

 within the protoplasm. The microscope has told 

 us plainly that these fundamental principles are 

 based upon machinery. The cell division (repro- 

 duction) is apparently controlled by the centro- 

 some ; the heredity by the chromosomes; the con- 

 structive metabolism by the nucleus in general, 



