816 Comparative Morphology of Chordates 



ized toil of factory, store, and office. Densely populated cities are 

 especially favorable for the development of malignant spots which 

 disseminate vice and crime. In general, they are biologically unhealth- 

 ful. It has already been suggested that man is becoming a slave to his 

 own machines. In several particulars, he faces the dangers of over- 

 specialization. His insatiable thirst for wealth, power, fame, and 

 dominance over his fellows is at the bottom of some of the most serious 

 troubles of his race. Nations, motivated by these passions, become like 

 carnivorous dinosaurs, putting their dependence on brute strength 

 and crushing and devouring weaker nations. 



The history of vertebrates gives man ample reason for confidence 

 that his race will, in one way or another, go progressively onward. 

 Throughout the history, that which was fit has survived as long as 

 environment permitted and, meanwhile, it has given rise to something 

 possessing greater potentialities. Throughout the welter of a reptilian 

 world, certain small obscure quadrupeds lived their unobtrusive lives 

 and survived while their dominant but stupid contemporaries, assisted 

 by a changing environment, fought and starved themselves out of 

 existence. It is possible that the future of primates may contain a 

 parallel episode. By virtue of sheer brute strength and great number of 

 individuals, temporary dominance may be achieved by human groups 

 most of whose individuals are intellectually inferior, intolerant, devoid 

 of altruism, and belligerent. It seems likely that, in the course of time, 

 such mutually antagonistic and unadaptable groups, assisted by the 

 economic consequences of overpopulation, may fight, crowd, and starve 

 themselves out of existence. But meanwhile, living unobtrusive lives or 

 surviving temporarily by retreat, some human minorities constituted 

 of individuals of superior intelligence and finer ideals, esteeming truth, 

 good, and beauty above power, speed, size, and vitiating luxuries and 

 pleasures, will carry forward the main line of evolution. 



The relatively near future of this biologic prospect may seem dis- 

 couraging, or even terrifying, if we have at heart the welfare of genera- 

 tions soon to follow us. There is, however, a possible alternative. Pri- 

 mates owe their present position in the world to the fact that they 

 inaugurated an entirely unique line of specialization. They did it un- 

 intelligently— we know not how, but it proved to be a line along which 

 the highest existing degree of animal intelligence has developed. Having 

 departed from traditional lines of evolutionary specialization, it may 

 be possible for the human primate, using the intelligence which he has 

 acquired, to break the precedent established by earlier vertebrate 

 races which were relatively low in mental capacity. At the present 

 moment, the human race seems to stand at a critical juncture in 

 its history. The crucial question is whether it will go on blindly 



