554 ALEXANDER PEDLER LECTURE 



mechanical principles of insensate forces. To-day that same ' life,' 

 spread among a myriad of individuals, is still flourishing, and shows no 

 signs of decline. It is an important, though superficial, part of the 

 economy of the globe. Its more progressive exponents, elaborating their 

 structural and mechanical diversities, have acquired an enhanced sensitive- 

 ness that has become concentrated into a definite nervous system, and has 

 gradually attained the faculty of intelligence. Being mammals ourselves, 

 vi^e can recognise in our fellow mammals mental capacity and consequent 

 behaviour that appeal to us as comparable with our own ; it is not possible 

 to appreciate the mentality of creatures utterly unlike ourselves, even if 

 such mentality exists. Nevertheless, it seems evident that reception of 

 sensations and response to them become more acute and intelligent with 

 improving brain-structure. Increasing faculties of locomotion stimulate 

 perception, and life becomes less automatic and more emotional. The 

 brain comes to dominate the organism. 



The earliest forms of life must have striven against their physical 

 surroundings, for life is an irritating alien in the inorganic world. But 

 when, by virtue of the faculty of multiplication, living things came to 

 exist in great quantity and congestion, internecine competition was added 

 to environmental problems, and the complicated anarchy of the ' struggle 

 for existence ' began. Structural advantages, or (in later stages) mental 

 superiority, help to bring success to their possessors ; but the struggle is 

 ultimately unavailing. For although the winners may crush, and perhaps 

 even exterminate, the losers in any particular rivalry, the factors that gave 

 them victory ensure their collapse. Unobtrusive types endure, but 

 aggressive and domineering types achieve success and disaster in direct 

 proportion. We can liken the course of evolution to the use of a cylinder 

 of gas. If the gas is allowed to escape slowly under control, it may burn 

 steadily, giving a feeble light, for a long time ; if it all ignites at once, 

 there is a brilliant flash, a crash, and then darkness. Such were the 

 records of Lingula and Productus, or of the Turtles and Dinosaurs. 



Mental acumen is a better means to success than mere structural 

 advantage. The rapid rise and fall of hosts of mammalian types, con- 

 trasting as it does with the considerable stability of the invertebrate fauna 

 during the Cainozoic era, seems a clear illustration of the paradox of the 

 struggle for existence, where the prize is death. 



And so once more we reach the depressing view of the human species, 

 surely the most spectacular and record-breaking winners yet evolved, 

 hastening towards the reward of victory. In so far as it has entered the 

 lists, matching its capacity for selfish greed against the individualism of 

 other animals or of its fellows, the human race is bound by the rules of 

 the competition, and the prize is within its grasp. Man is a supremely 

 successful animal ; such success, whether involving murder or not, is the 

 precursor of suicide. 



There can be no doubt that the introduction of life marked a crisis in 

 the earth's history. Perhaps its significance can be best expressed by 

 the suggestion that to the eternal changelessness of physical laws there 

 was added the eternal changefulness of organic evolution. Bound by the 

 insensitive chains of material environment, living organisms possessed a 

 sort of individuality of which they became increasingly conscious with the 



