THE VITAL ORDER 



and valves is a pump that forces the blood through 

 the system, but a pump that works itself and does 

 not depend upon pneumatic pressure — a pump in 

 which vital energy takes the place of gravitational 

 energy. The peristaltic movement in the intestines 

 involves a mechanical principle, but it is set up by 

 an inward stimulus, and not by outward force. It 

 is these inward stimuli, which of course involve 

 chemical reactions, that afford the motive power for 

 all living bodies and that put the living in another 

 order from the mechanical. The eye is an optical 

 instrument, — a rather crude one, it is said, — but 

 it cannot be separated from its function, as can a 

 mere instrument — the eye sees as literally as the 

 brain thinks. In breathing we unconsciously apply 

 the principle of the bellows; it is a bellows again 

 which works itself, but the function of which, in a 

 very limited sense, we can inhibit and control. An 

 artificial, or man-made, machine always implies an 

 artificer, but the living machine is not made in any 

 such sense; it grows, it arises out of the organizing 

 principle that becomes active in matter under con- 

 ditions that we only dimly understand, and that we 

 cannot reproduce. 



The vital and the mechanical cooperate in all 

 our bodily functions. Swallowing our food is a 

 mechanical process, the digestion of it is a chemical 

 process and the assimilation and elimination of it 

 a vital process. Inhaling and exhaling the air is a 



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