326 THE POPULAR SCIENCE MONTHLY. 



our motives, conscious of the portentous change which is taking place 

 in the thought of the world, conscious of the irresistible power which 

 is behind us ! Let us not return railing for railing, but, above all, let 

 us deliver unflinchingly to others the truths that Nature has delivered 

 to us! 



The book of Nature ! shall not we chemists, and all our brother- 

 students, whether they be naturalists, astronomers, mathematicians, 

 geologists, shall we not all humbly and earnestly read it ? Nature, 

 the mother of us all, has inscribed her unfading, her eternal record on 

 the canopy of the skies, she has put it all around us on the platform 

 of the earth ! No man can tamper with it, no man can interpolate or 

 falsify it for his own ends. She does not command us what to do, nor 

 order us what to think. She only invites us to look around. For 

 those who reject her she has in reserve no revenges, no social ostra- 

 cism, no index expurgatoHus, no auto-da-fe ! To those who in purity of 

 spirit worship in her heaven-pavilioned temple, she offers her guidance 

 to that cloudy shrine on which Truth sits enthroned, " dark with the 

 excess of light ! " Thither are repairing, not driven by tyranny, but 

 of their own accord, increasing crowds from all countries of the earth, 

 conscious that, whatever their dissensions of opinion may heretofore 

 have been, in her presence they will find intellectual concord and 

 unity. 







MENTAL OVERWORK. 



By EOBEET FAEQUHAESON, M.D. 



TO hit off the happy medium between over- and under-work is no 

 easy task even to those who have the necessary knowledge, on 

 the one hand, and the liberty to arrange their own scheme of occupa- 

 tion, on the other. But, for one person who is injured by doing too 

 much, I quite believe with Dr. Wilkes that many may be found who 

 are sustaining serious damage from not having enough mental stimu- 

 lus. The listless vacuity in which so many of the well-to-do classes 

 spend their lives, the want of any incentive to exertion, and the ab- 

 sence of any attempt at real thought which the wide-spread prevalence 

 of ready-made opinions in our periodical literature directly encour- 

 ages, must cause more or less degeneration of intellectual power. Un- 

 der these conditions the brain gradually loses its healthy tone, and, 

 although quite equal to the daily calls of a routine and uneventful ex- 

 istence, it is unable to withstand the strain of special sudden emer- 

 gency, and, when a heavy load of work is unexpectedly thrown upon 

 it in its unprepared state, then we see all the worst consequences of 

 what may be called overwork develop themselves. It is no uncom- 



