OF FUNCTION; OR, HOW WE ACT. 15 



and blended into one. The structure itself is the 

 seat of the power. The very muscles, that contract, 

 decompose ; the brain and nerves themselves, in 

 their decay, originate the nervous force. It is as if 

 the wheels of the steam-engine were made of coal, 

 and revolved by their own combustion ; * or as if the 

 watch-spring, as it expanded, pointed to the hour. 

 HerelT'a broad distinction between all contrivances 

 of ours and living organisms, and this made it the 

 harder to perceive the essential correspondence. For 

 the burning of the coal (an organic substance) to 

 move an iron wheel, differs only in detail, and not in 

 essence, from the decomposition of a muscle to effect 

 its own contraction. Indeed, we are not justified in 

 affirming, absolutely, that there is even this difference 

 of detail. It may not be the very same portion of 

 the muscle which decomposes and contracts ; the 

 power and the mechanism may be as truly separate 

 in the body as in any machine of our own contriving, 

 and only so closely brought together as to defy our 



* The catharine-wheel is an instance of this very thing: 

 and power united. But the firework is not renewed as it decomposes; 

 the " nutrition " is wanting. 



