EQUILIBRATION. 513 



equilibration is suddenly effected), the ordinary balance is 

 by and by re-established: the returning appetite is keen in 

 proportion as the waste has been large; while sleep, sound 

 and prolonged, makes up for previous wakefulness. Kot 

 even in those extreme cases where some excess has wrought 

 a derangement that is never wholly rectified, is there an 

 exception to the general law; for in such cases the cycle 

 of the functions is, after a time, equilibrated about a new 

 mean state, which henceforth becomes the normal state of 

 the individual. Thus, among the involved rhythmical 

 changes constituting organic life, any disturbing force that 

 works an excess of change in some direction, is gradually 

 diminished and finally neutralized by antagonistic forces; 

 which thereupon work a compensating change in the oppo- 

 site direction, and so, after more or less of oscillation, restore 

 the medium condition. And this process it is, which 

 constitutes what physicians call the vis medicatrix na- 

 turce. The third form of equilibration displayed by 



organic bodies, is a necessary sequence of that just illustrated. 

 When through a change of habit or circumstance, an organ- 

 ism is permanently subject to some new influence, or differ- 

 ent amount of an old influence, there arises, after more or 

 less disturbance of the organic rhythms, a balancing of them 

 around the new average condition produced by this addi- 

 tional influence. As temporary divergences of the organic 

 rhythms are counteracted by temporary divergences of a re- 

 verse kind; so there is an equilibration of their permanent 

 divergences by the genesis of opposing divergences that are 

 equally permanent. If the quantity of motion to be ha- 

 bitually generated by a muscle, becomes greater than before, 

 its nutrition becomes greater than before. If the expendi- 

 ture of the muscle bears to its nutrition, a greater ratio than 

 expenditure bears to nutrition in other parts of the system; 

 the excess of nutrition becomes such that the muscle grows. 

 And the cessation of its growth is the establishment of a bal- 

 ance between the daily waste and the daily repair — the 



