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to a point d, on the screen, then the point D’ which is the image 
of the foreign body D, will be in the line of vision. We may now 
bring two points P, and P, on a wire to coincide with this line of 
vision. If now the eye is moved to another point, O,, these two 
points P, and P, will no longer be in the line of vision directed to 
d,. If now the wire P,P, be moved parallel with itself so that 
P, touches the new line of vision, then the point P will indicate 
the position of the foreign body. Wherever the eye moves, so long 
as the anticathode follows the movement, the point P, will coincide 
with the image of D’ and is, so to say, closely connected with it. 
We have now only to measure the distance of P, from the screen, 
in order to know with mathematical accuracy, how far D lies behind 
the sereen. This method I have called Metaphanometry. 
We may go even further. Let us suppose D to be a foreign body, 
a bullet for instance. We may place a similar bullet at D’. If now 
we replace the sereen 5 by a plate-glass mirror, we shall see the 
reflected image of the bullet D apparently in the patient's body at 
D, that is in exact coincidence with the bullet in the body, so that 
the surgeon can proceed to operate as if he had the bullet actually 
before him. This method we may call Metasymphany. 
I have come to the above conclusions on theoretical grounds but 
I have convinced myself by simple models and experiments that the 
method holds good in practice. | made my first experiments in 
polyphany and metaphany in Friepricn Dessaver’s laboratory at 
Aschaffenburg, the first symphanator exposure in Prof. WENCKEBACH’S 
laboratory at Groningen. How far the method may prove of service 
in practice,can only be determined by long experience and the 
adaptation of Röntgen instrumentation for the purpose. 
(April 22, 1909). 
