[. Bead before the Academy April 2, 1897.1 
EXPERIMENTS WITH X-EAYS UPON THE BLIND. 
BY DBS. H. L. HILGAKTNEB AND EJ E. NOKTHKUP. 
Since the experiments made by Hertz upon electric radiation, verifying 
the theory of Maxwell that induction is propagated in time, thereby dem- 
onstrating the existence of an ether, no scientific discovery has given rise 
to such widespread popular - interest and extensive experimentation as 
Roentgen’s remarkable chance revelation of the existence and the strange 
properties of the radiation from a Crooke’s vacuum tube. Though physi- 
cists and physicians all over the world have been actively engaged in 
striving to add to the facts first set forth by Roentgen in his original pa- 
per, very little indeed has been added to our knowledge of the X-rays 
beyond what was given in this paper, now a little over a year old, which 
announced their discovery. 
Though X-ray myths and theories are rife, physicists do not yet know 
what these rays are, nor have their proper relations to other well known 
phenomena as yet been pointed out. Things which are mysterious and 
not understood are generally assumed to possess hidden potencies which 
they do not possess. Many have looked to the X-rays hoping to find in 
them an agency for exciting vision in the totally blind. Reports of some 
very remarkable results of X-ray experiments upon the blind have, from 
time to time, appeared in the daily press .and occasionally in the scientific 
journals. A letter from Dr. Louis Bell to the editor of The Electrical 
World, which was published in this journal December 12, 1896, stimu- 
lated the authors, especially in view of the extraordinary claims made in 
the letter, and the abundant material at our disposal, to carry on some 
experiments which should either verify or contradict the statements 
which came under our notice. 
Dr. Bell claimed that his subject, a totally blind man, in whom blind- 
ness was due to paralysis of the optic nerve, was able to plainly distin- 
guish the flickering of the Crooke’s tube. A metal sheet cut off this vision 
entirely, and the subject was able to see a hunch of keys, the fingers, etc., 
shadowed upon the illuminated surface of the tube. Dr. Bell says that 
“the interesting feature of the experiment was this: a sheet of cardboard 
cut off vision as completely as the metal, and the subject could see forms 
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