FUNDAMENTAL RELATIONS OF ANIMALS 17 



details upon this subject, especially since it is discussed more fully 

 below.^^ 



It might perhaps be urged that animals living together in excep- 

 tional conditions and exhibiting structural peculiarities apparently 

 resulting from these conditions, such as the blind fish,-^ the blind 

 crawfish, and the blind insects of the Mammoth Cave in Kentucky, 

 furnish uncontrovertible evidence of the immediate influence of 

 those exceptional conditions upon the organs of vision. If this, how- 

 ever, were the case, how does it happen that that remarkable fish, the 

 Amblyopsis spelceus, has only such remote affinities to other fishes? 

 Or were, perhaps, the sum of influences at work to make that fish 

 blind capable also of devising such a combination of structural char- 

 acters as that fish has in common with all other fishes, with those 

 peculiarities which at the same time distinguish it? Does not, rather, 

 the existence of a rudimentary eye discovered by Dr. J. Wyman in 

 the blind fish show that these animals, like all others, were created 

 with all their peculiarities by the fiat of the Almighty, and this rudi- 

 ment of eyes left them as a remembrance of the general plan of struc- 

 ture of the great type to which they belong? Or will, perhaps, some 

 one of those naturalists who know so much better than the physicists 

 what physical forces may produce, and that they may produce, and 

 have produced every living being known, explain also to us why 

 subterraneous caves in America produce blind fishes, blind Crustacea, 

 and blind insects, while in Europe they produce nearly blind rep- 

 tiles? If there is no thought in the case, why is it then that this very 

 reptile, the Proteus angumus, forms, with a number of other rep- 

 tiles living in North America and in Japan, one of the most natural 

 series known in the animal kingdom, every member of which ex- 

 hibits a distinct grade^^ in the scale? ^^ 



After we have freed ourselves from the mistaken impression that 

 there may be some genetic connection between physical forces and 



^ See below, Sect. ix. 



^* Jeffries Wyman, "Description of a Blind Fish, from a Cave in Kentucky," American 

 Journal of Science, XLV (1843), 94-96, and XVII (2d ser., 1854), 258-261; Agassiz, "Ob- 

 servations on the Blind Fish of the Mammoth Cave," in ibid., XI (2d ser., 1851), 127- 

 128. 



^ See below. Sect. xii. 



^ [Darwin in Chapter V of the Origin of Species was very specific in disputing Agas- 

 siz on this evidence, employing the example of the eyeless fish as proof of the influence 

 of natural selection through the use and disuse of parts.] 



