WASTE AND REPAIR. 217 



newal less than that which would have followed the greater 

 inactivity of slumber. We know, too, that when exhausted 

 by labour, sitting brings a partial return of vigour. And 

 we also know that after the violent exertion of running, 

 a lapse into the less violent exertion of walking, results in a 

 gradual disappearance of that prostration which the running 

 produced. This series of illustrations conclusively proves 

 that the rebuilding of the organism is ever making up for 

 the pulling down of it caused by action; and that the effect 

 of this rebuilding becomes more manifest, in proportion as 

 the pulling down is less rapid. From each digested meal 

 there is every few hours absorbed into the mass of prepared 

 nutriment circulating through the body, a fresh supply of 

 the needful organic compounds; and from the blood, thus 

 occasionally re-enriched, the organs through which it passes 

 are ever taking up materials to replace the materials used up 

 in the discharge of functions. During activity the reinte- 

 gration falls in arrear of the disintegration ; until, as a conse- 

 quence, there presently comes a general state of functional 

 languor; ending, at length, in a quiescence which permits 

 the reintegration to exceed the disintegration, and restore the 

 parts to their state of integrity. Here, as wherever there 

 are antagonistic actions, we see rhythmical divergences on 

 opposite sides of the medium state changes which equilibrate 

 each other by their alternate excesses. (First Principles, 

 85, 173.) 



Illustrations are not wanting of special repair that is 

 similarly ever in progress, and similarly has intervals during 

 which it falls below waste and rises above it. Every one 

 knows that a muscle, or a set of muscles, continuously strained, 

 as by holding out a weight at arm's length, soon loses its 

 power ; and that it recovers its power more or less fully after 

 a short rest. The several organs of the special sensations 

 yield us like experiences. Strong tastes, powerful odours, loud 

 sounds, temporarily unfit the nerves impressed by them for 

 appreciating faint tastes, odours, or sounds; but these inca- 



