94 THE MAMMOTH CAVE. 
of the geographical distribution of animals, that 
they were created under the circumstances in- 
which they now live, within the limits over 
which they range, and with the structural pecu- 
liarities which characterize them at the present 
day. But this is a mere inference, and whoever 
would settle the question by direct experiment 
might be sure to earn the everlasting gratitude 
of men of science. And here is a great aim for 
the young American Naturalist who would not 
shrink from the idea of ee his e to the 
solution of one great question.”* 
* It will be seen from the foregoing that Professor Agassiz main- 
tains the opinion that the fish and the crawfish of the Cave, with 
their structural peculiarities, ‘were created under the circum- 
stances in which they now live,” but, as he very frankly adds, 
“this is a mere inference.” 
We have already stated that the inference drawn from our 
own observations and reflections is that these animals were 
originally supplied with the organs of vision; and since the 
above was penned we have noticed that Professor Joseph Jones, 
of Nashville, Tenn., has incidentally corroborated our view while 
treating the subject of Albznesm. Referring to the effects of con- 
tinued darkness upon various animals, Dr. Jones remarks : 
« After extended investigution and examination of thousands 
of living specimens, I have never observed an albino among cold- 
blooded animals. 
‘When this class of animals have been confined in dark caves, 
and excluded from the action of light, they present the appear- 
ance of the albino; and it is probable that, if the negro children, 
