CONSCIOUSNESS AS A VITAL FUNCTION 295 



probable evolutionary history of the animal kingdom, 

 we see that muscle has grown up out of protoplasmic 

 organization of simpler, i.e., less differentiated, sort. 

 Contractility is a function of all protoplasm, but 

 muscle as tissue is a later differentiation. The muscu- 

 lar systems as we see them in the human body are 

 new structures, appearing at a definite stage of 

 animal differentiation, both ontogenetically and phy- 

 logenetically. But they were not fabricated out of 

 nothing. The origin of this new organic pattern is a 

 natural process and the working of the completed 

 mechanism is also a natural activity. 



The evidence is that the organs of the human mind 

 have gradually grown up phylogenetically and onto- 

 genetically in a similar way, by natural process. And 

 the adult working of these organs is similarly a nat- 

 ural process. No mystic forces are involved. Certain 

 combinations of bodily processes (excitation of end- 

 organs, conduction in nerves, etc.) act upon nervous 

 tissue of very special organization (chiefly in the 

 cerebral cortex) whose functions are in part physi- 

 ological processes observable by the ordinary tech- 

 nique of the physiological laboratory (metabolism of 

 tissue, changes in electrical potential, etc.) and in 

 part directly as subjective awareness while the process 

 is in action. 



This is not an "awareness of an awareness," nor of 

 any activity as physiological process (for we do not 

 directly experience nerves as conducting, etc.), nor 



