JoLY — The Abundance of Life. 



79 



On this diagram a reproductive act, on the part of the organism 

 is represented by a line which repeats the curvature of the parent 

 organism originating at such a point as P in the path of the latter 

 when the rate of consumption of energy has become constant. 

 The organism A has now ceased to act as a unit. The products 

 of fission each carry on the vital development of the species along 

 the curve B, which may be numbered (2), to signify that it repre- 

 sents the activity of two individuals, and so on, the numbering 

 advancing in geometrical progression. The particular curvature 

 adopted in the diagram is, of course, perfectly imaginary ; but it 

 is not of an indeterminable nature. Its average course for any 

 species is a characteristic of fundamental physical importance, 

 regarding the part played in nature by the particular organism. 



Time. 



Fig. 2. Life- Curves of Fri??tiiive Organistns. 



In figure 2 is represented the path of an imaginary primitive 

 multicellular organism before the effects of competition produced 

 or fostered its mortality. The lettering of figure 1 applies ; the 

 successive reproductive acts are marked Pi, Pg ; Qi, Q2, &c., in the 

 paths of the successive individuals. 



The next figure (fig. 3) crudely illustrates the origination of 

 death in organic history, that is death by animate environmental 

 causes. I have called this " interference," for whatever hypothesis 

 we make as to the origin of death, the fact itself is evidently the 

 result of opposing forces bringing the activity of the organism to 



