Sight in Savages. 181 
mistake which eye specialists and writers on the 
eye make is that they think too much about the 
eye. When they affirm that the conditions of our 
civilization are highly injurious to the sight, do 
they mean all the million conditions, or sets of 
conditions, embraced by our system, with the 
infinite variety of occupations and modes of living 
which men have, from the lighthouse-keeper to the 
worker underground, whose day is the dim glimmer 
of a miner’s lamp? ‘‘ An organ exercised beyond 
its wont will grow, and thus meet increase of 
demand by increase of supply,” Herbert Spencer 
says; but, he adds, there is a limit soon reached, 
beyond which it is impossible to go. This increase 
of demand with us is everywhere—now on this 
organ and now on that, according to our work and 
way of life, and the eye is in no worse case than 
the other organs. There are among us many cases 
of heart complaint ; civilization, in such cases, has 
put too great a strain on that organ, and it has 
reached the limit beyond which it cannot go. And 
so with the eye. The total number of the defective 
among us is no doubt very large, for we know that 
our system of life retards—it cannot effectually 
prevent—the healthy action of natural selection. 
Nature pulls one way and we pull the other, com- 
passionately trying to save the unfit from the 
consequences of their unfitness. The humane in- 
stinct compels us; but the cruel instinct of the 
savage is less painful to contemplate than that 
mistaken or perverted compassion which seeks to 
