JoLY — The Abundance of Life. 



81 



crystallization, would appear as lines sloping downwards from left 

 to right. 



Thus, upon the primitive organism, a time-limit to activity- 

 has been of necessity imposed by the activity of a series of derived 

 units, each seeking energy, and in virtue of its adaptation each 

 more fitted to obtain it than its predecessor. But, whatever our 

 views on this matter may be, we have to recognise a periodicity of 

 functions in the life-history of the successive individuals of the 

 present day ; and whether or not we trace this directly or indi- 

 rectly to a sort of interference with the rising wave of life, or 

 even leave the latter out of account altogether in the origination 

 or perpetuation of death, the truth of the diagram (fig. 4) holds in 



Fig. 4. Life- Waves of a Species. 



so far as it may be supposed to graphically represent the dynamic 

 history of the individual. The point chosen on the curve for the 

 origination of a derived unit is only applicable to certain organisms, 

 many reproducing at the very close of life. A chain of units 

 are supposed here represented: the periodicity is not necessarily 

 ascribable to external forces, but is inherited. 



Drawing the tangent and normal at the beginning and end- 

 ing of any one complete vibration the total energy consumed 

 by the organism during life is the length E on the axis of 

 energy, and its period of life is the length T on the time-axis. 



E 



The mean activity is the quotient — . 



SCIENT. PROC. R.D.S. — VOL. VII., PART I. G 



