XXXII 
PROBLEM OF CAVE BLINDNESS 
RE-EMINENT as man is, compared with 
other creatures, there are few of the deeper 
problems of Natural History which have not a 
practical bearing on human affairs. The touch of 
animate protoplasm makes the whole living world 
kin; and if we knew with certainty how it has come 
about that many cave-animals are blind or have ill- 
developed eyes, we should be able to think more 
clearly in regard to some dwellers in darkness 
nearer home. Let us turn, then, sympathetically 
to the fact of cave blindness, and to some notable 
recent contributions to the evolutionary problem 
which it raises. Dry caves have never more than 
casual tenants, but damp caves harbor many 
creatures—from salamanders to wood-lice—which 
are in the strict sense at home there. The list of 
Troglodytes is more extensive than honorable, for 
leaving out of account the numerous bats and a few 
peculiar mice, which rest in the cave but feed by 
night outside of it, thus making the best of two dark 
worlds, we find that the bulk of the cavernicolous 
fauna is rather weedy. There are few cave-dwelling 
animals of the desperado type that we associate 
with Adullam; most of them are handicapped by 
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