264 CURVATURES AND MOVEMENTS, ETC. 



not only the structures and phenomena recorded in this com- 

 munication should be recognised as in accordance with the 

 principles of organisation, but also that the generalisation of 

 these structures and phenomena, as apparently determined 

 by the law of the equiangular spiral, should be found to 

 supply the requirements of these principles. 



36. The principle involved in the gain of time provided 

 for repose after functional activity in organic structure is still 

 further illustrated by an arrangement in organic joints, first 

 indicated in my former communication on this subject. All 

 organic joints consist of at least two articular couples, or of 

 two articular combinations. The two couj^les or two com- 

 binations are so arranged that during the full action of the 

 joints — i.e., during the performance of its two opposite move- 

 ments — the one couple or combination performs the work 

 during the first half of the first movement and the last half 

 of the second movement, while the other couple or combina- 

 tion performs the work during the last half of the first move- 

 ment and the first half of the second movement. The effect of 

 this arrangement is, that each of the two couples or combina- 

 tions is alternately in action and out of action. While the 

 one couple or combination is doing work and undergoing de- 

 terioration, the other couple or combination is relieved from 

 functional activity, and engaged in its own necessary repara- 

 tion — that is, in its own nutritive actions. 



