i6o THE POPULAR SCIENCE MONTHLY. 



repair the injury, otherwise very slow at healing. In some similar 

 way it must be that a small seed of a plant selects just such ingredi- 

 ents from the soil as shall make it thrive and increase. On these or- 

 ganic powei's of initiation and selection, Lucretius ponders in his great 

 poem, and wonders how it is that different animals the pig, dog, and 

 fowl eat the same food and yet make of it such diverse substance. 

 On a seed's peculiar nature it may follow whether a field shall give 

 its substance to maples or cabbages. Just so a volcanic island's pop- 

 ulation depends, to a large extent, on the first comers on what human 

 tribe first lands there, what seeds and insects are first wafted upon it, 

 and what birds first alight on its shores. Once in possession, the pro- 

 cess of multiplication soon renders occupancy by stray creatures of 

 superior kinds impossible ; and so we have incidentally a case where 

 the best may not be the conquerors and survivors. Mere precedence 

 in time is often of much account. No man shall ever have as many 

 children as Adam. The first poets exhausted the most striking and 

 beautiful similes in Nature, such as now may independently but use- 

 lessly occur to every cultured imagination. The limits of choice in 

 the subjects for invention, authorship, and art, are constantly nar- 

 rowed by the occupation of territory by those who have gone before. 

 Of course, infinite additions to knowledge and achievement are pos- 

 sible, but many efforts suggested by the wants of the time, though 

 quite original, are fruitless simply because they do not happen to be 

 first. 



With respect to the great effectiveness of force, when used largely 

 or totally in initiation, Pi'of. Stewart thinks that intelligence depends 

 on conditions in the organism of unstable equilibrium, and he draws 

 a parallel between the great powers of a human mind and the marked 

 decomposibility of its brain-substance. The particular supremacy of 

 man in Nature is thus traced to a principle which highly characterizes 

 his own frame, and of which he avails himself in his mastery of ex- 

 ternal Nature delicacy of poise in construction rendering lai-ge pow- 

 ers obedient to slight ones. 



Our subject further suggests the importance of leadership among 

 mankind. Heroes have been so unduly praised that a reaction has 

 set in with many thinkers, who would deti-act from their real value. 

 Popular discontent, or a wide-spread spirit of enterprise, often lingers 

 in useless agitation for want of some man a little bolder than the rest, 

 who shall make the first onslaught on tyranny, or captain the first 

 ship that shall set its prow toward the shores of a new world. To be 

 sure, a hero is no more than a representative of the strong feelings of 

 his land and time; yet, without his faith and enthusiasm, perhaps but 

 little more than that of many of his neighboi's, their desires and hopes 

 might never have fulfillment. 



Finally, our theme shows us the immense difficulties in the way of 

 reducing some inquiries of deep interest to exact treatment. If the 



