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VII. 



THE ABUNDANCE OF LIFE. By J. JOLY, M.A., B.E., Assistant 

 to the Professor of Civil Engineering, Trinity College, Dublin. 



[Read November 19, 1890.] 



"We liad reached tlie Pass of Tre Croci^ and from a point a little 

 below the summit, looked eastward over the glorious Yal Buona. 

 The pines which clothed the floor and lower slopes of the valley, 

 extended their multitudes into the furthest distance, and among 

 the many recesses of the mountains, and into the confluent Val di 

 Mesurina. In the sunshine the Alpine butterflies flitted from stone 

 to stone. The ground at our feet teemed with small black ants, as 

 if the dead needles of the pines had come to life. 



It was a magnificent display of vitality ; of the aggressiveness 

 of vitality, assailing the barren heights of the limestone, wringing a 

 subsistance from dead things. And the question suggested itself 

 with new force: why the abundance of life and its unending 

 activity ? 



In trying to answer this question, the present sketch origi- 

 nated. 



I propose to refer for an answer to dynamic considerations. 

 It is apparent that natural selection can only be concerned in 

 a secondary way. Natural selection defines a certain course of 

 development for the organism ; but very evidently some property of 

 inherent progressiveness in the organism must be involved. The 

 mineral is not affected by natural selection to enter on a course of 

 continual variation and multiplication. The dynamic relations 

 of the organism with the environment are evidently very different 



1 In the Dolomites of South-east Tyrol. So much of what follows was evolved in the 

 course of conversation with my fellow-traveller, Mr. Henry H. Dixon, that I had 

 wished this essay to be a joint one ; but at Mr. Dixon's request, I have undertaken 

 the authorship. 



