THE MAMMOTH CAVE. 85 



eventually obliterated. In the never-ceasing 

 darkness of the Cave, eyes are unnecessary or- 

 gans to the fish that live in its waters. We 

 have every reason to believe that these fish were 

 originally possessed of eyes ; but after their in- 

 troduction into the Cave, and perhaps centuries 

 of existence there, these useless organs grad- 

 ually, through many generations, lost their ori- 

 ginal character, and finally disappeared, only a- 

 trace of the orbit remaining.* 



Some months after our visit to the Cave our 

 attention was drawn to a newspaper article, from 

 an anonymous writer, which we believe originally 

 appeared in the Chicago ''Tribune," August 18, 

 18G7. The writer contended that the permanent 

 inhabitants of the Cave were not only blind, but 

 deaf also. The original letter in the " Tribune"' 

 was entitled "Important Scientific Observations," 



* " Their exclusion from tiie solar beam is well known to pro- 

 duce organic alterations in the visual organs of animals, such as 

 atrophy of the optic nerve, or those portions of the brain (the 

 corpora quadrigemina) more immediately associated with the 

 sight. It is supposed that the blindness observed among fish 

 found in the dark caves of the Tyrol and Kentucky arises from 

 the arrest in the development of the eyes as the result of a con- 

 stant deprivation of light." — Light: its Influence on Life and 

 Health. By Forbes Winslow, M.D., etc., American ed. New 

 York: Moorhead, Simpson & Bond, 18G8, p. 13. 



8 



