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THE POPULAR SCIENCE MONTHLY. 



EDITOR'S TABLE. 



DU BOIS-REYMOND ON EXERCISE. 



MAGAZINES are of two kinds: 

 the entertaining kind, which 

 cater to mental laziness, and can be 

 skimmed over without mental effort; 

 and the instructive kind, which con- 

 tain articles that must be read twice. 

 " The Popular Science Monthly," from 

 the start, has furnished a considerable 

 proportion of articles so weighted with 

 valuable thought as to require concen- 

 tration of mind and often careful re- 

 perusal to grasp and assimilate their 

 contents. This has provoked frequent 

 protests on the part of our readers, who 

 have complained that we deviate from 

 the magazine-standard of easy reading, 

 and are not true to our title, which 

 promises a magazine adapted to the pop- 

 ulace. Yes, but to the improvement of 

 the populace! The "Monthly" was 

 started for no other reason than be- 

 cause the standard of our current maga- 

 zines was low too low to reflect the 

 best mental activity of the times. Their 

 aim is to amuse and beguile their read- 

 ers by calling forth the smallest possible 

 amount of mental reaction. "We started 

 because the popular magazines, com- 

 peting downward, shirked vigorous 

 work, and were false to the demands 

 of an age characterized beyond all oth- 

 ers for its intellectual seriousness, and 

 by the magnitude, importance, and prac- 

 tical quality of the questions that are 

 occupying the ablest minds in all coun- 

 tries. These minds can not be followed 

 these questions can not be under- 

 stood without effort on the reader's 

 part. This is the price that must be 

 paid for real knowledge. People can 

 not be amused into mental grasp and 

 vigor, they must be exercised into it. 

 We talk of mental progress, mental ele- 



vation, mental expansion, but these are 

 attainable only on the condition of men- 

 tal exertion. 



We print, in two parts, another of 

 those articles that have to be re-read to 

 get their full import. It is by Professor 

 Du Bois-Reymond, and is on "Exer- 

 cise," so that it is at the same time an 

 illustration and an exposition of our 

 subject. It is a most original and in- 

 structive statement, and will well repay 

 reperusal. 



One of the inevitable effects of the 

 advancement of science in various di- 

 rections is the establishment of new 

 connections of thought which are often 

 most striking and significant. What 

 can Darwinism have to do with exer- 

 cise ? Restricting the term Darwinism, 

 as we must do, to natural selection, 

 Du Bois-Reymond shows that they are 

 very closely related. Viewing organic 

 nature mechanically, the series of living 

 beings has been unfolded during un- 

 limited time by adaptation to new con- 

 ditions, the course of movement being 

 in an ascending scale. " From this 

 point of view, organic nature appears 

 not only as a machine, but also as a 

 self-improving machine." But the law 

 of self-improvement is, that powers and 

 faculties are strengthened and grow by 

 exercise, and are weakened by non- 

 exercise. In the struggle for existence, 

 therefore, those will win and survive in 

 whom exercise has developed superior 

 capacities and resources, while the less 

 exercised and weaker fail and perish. 

 The principle of exercise is thus a kind 

 of motive-power in animal evolution, 

 and, as might be expected, is full of the 

 most important results in the higher 

 spheres of physiological and psychical 

 activity. 



