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Scientific Proceedings, Royal BuUin Society. 



a close, and these forces; whether originating within the organism 

 and fostered by natural selection or not, owe their development to 

 the activity of the rival organisms. Thus, as the numbers increase, 

 the earlier and more worn individuals are feeling the effects of 

 natural selection bringing abler combatants and competitors into 

 the field, and their rate of consumption of energy is diminishing 

 (point A on the diagram) . This progresses in the successive indi- 

 viduals according as they have been exposed to the ravages of time. 

 Their paths ever turn more and more from the axis of energy, till 



Time. 



Fig.3. Coinnmicing interfennce ofFj-imitive Organisms. 



at length the point is reached when no more energy is available to 

 the older members ; a tangent to the curve at this point is at right 

 angles to the axis of energy and parallel to the time axis. The 

 death point is reached, and however great a length we measure 

 along the axis of time, no further consumption of energy is indi- 

 cated by the path of the organism. Drawing the line beyond the 

 death point is meaningless for our present purpose. 



It is observable that while the progress of animate nature finds 

 its representation on this diagram by lines sloping upwards from 

 left to right, the course of events in inanimate nature — for example, 

 the history of the organic configuration after death, or the changes 

 progressing — let us say, in the solar system, or in the process of a 



