Proofs of Erolvtlon. 289 



the forces that lead to industry and thrift, and on to the 

 highest plane of moi'al well-being. 



It teaches the principles of adjustment aiul harnion}- ; it 

 bids us always to take thought for the morrow, and proclaims 

 that love and labor united constitute the " divinity that 

 shapes our ends." It will make the world more generous, 

 kind, and charitable ; more patient, brave and true ; more 

 lunuble. gentle, and unselfish; more noble, virtuous and 

 patriotic. It will do all this because it asserts the great 

 law of mutual duty. Evolution affirms the survival of the 

 fittest. It prophesies even better things to come, than those 

 which we now know. It points toward an ideal of perfec- 

 tion. Its flower and fruitage in life is moral grandeur. 



Admitting its scope and possibilities, as thus portrayed, 

 we are now at the threshokl of the vital question, " Is Evo- 

 lution true ? " For nothing false can be a permanent good. 

 This question must be answered briefly and imperfectly ; 

 for an hour gives time barely to mention the various phases 

 of the great theme. We are compelled to take a hasty view 

 of the broad field, touching only the mountain peaks in the 

 line of proof which establishes the theory of Evolution. 



What is Evolution ? A late writer has tersely defined it 

 as follows : " Evolution is continuous, progressive change, 

 according to certain laws, and by means of resident forces." 

 Evolution is simply growth and change, governed by fixed 

 laws. Its corner stone is continuitij. 



The Essayists who have preceded me have explained to 

 you Solar and Planetary Evohition, as also the Evolution of 

 the Earth as a whole, of Vegetal and Animal Life, of Mind, 

 of Man, of Society, Theology and Morals. It is in the field 

 of Biology, however, that the proofs of Evolution are most 

 abundant and conclusive. To this line of proof I shall 

 mainly confine my attention. But before proceeding to 

 details, it may be well to point out the 



FOUR CxREAT FACTORS OF EVOLUTION, 



on which the entire theory rests. These are (1) The influ- 

 ence of Environment ; (2) The increased use or disuse of 

 organs ; ('^) Natural Selection, or Survival of the Fittest ; 

 and (4) Sexual Selection. The two former are accredited 

 to Lamarck and others, but the two latter are wholly Dar- 

 winian; and running through all is the potent influence of 

 heredity. 



