26 ETHICAL ASPECTS OF EVOLUTION 



evolution, are, in fact, a sure source of retrogression. It 

 has been remarked by Dr. Archdale Reid 1 that species 

 undergo evolution only under adverse conditions, and 

 degeneration only under beneficial conditions . Prof. Ray 

 Lankester, in his short essay on Degeneration? writes to 

 the same effect : Any new set of conditions occurring to 

 an animal which render its food and safety very easily 

 attained seem to lead, as a rule, to degeneration. The 

 habit of parasitism clearly acts upon animal organization 

 in this way. Let the parasitic life once be secured, and away 

 go legs, jaws, eye, and ears ; the active, highly-gifted crab, 

 insect, or annelid, may become a mere sac, absorbing 

 nourishment and laying eggs. And Prof. Geddes : The 

 reversion exhibited by so many species among the higher 

 arthropods from sexual reproduction to more primitive 

 forms of genesis is explained by pointing out that such 

 species are peculiarly situated in obtaining abundant food 

 with little exertion. 3 



Prof. Lankester compares the purely physiological results 

 with what occurs in a higher and more complex level of 

 life, and observes that, in the same way, an active healthy 

 man sometimes degenerates when he becomes suddenly 

 possessed of a fortune, and Rome degenerated when pos 

 sessed of the riches of the ancient world. He might have 

 added that degeneration appears to be no more likely than 

 progression to bring about extinction. We have no reason 

 to believe that parasites are losing ground in the struggle 

 for existence, or that peoples who have been able to establish 

 permanent relations in subordination to a dominant race 

 have forfeited anything of their fitness to survive. 



An examination of the results of artificial selection will 

 confirm the view that increased complexity is no criterion 

 of fitness to survive, and, at the same time, explain why 

 it should not be. It will, I think, be admitted that, whatever 

 results breeders and horticulturists may have secured, 



1 Principles of Heredity, p. 158. 



2 E. Ray Lankester, Degeneration, p. 33. 



3 Evolution of Sex, p. 287. 



