The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1898-05-01
\ RAYS.
A London Surgeon Makes n Very Impor.
tsnt Invention.


tsnt Invention.
London Correspondence Chicago Chron-
iclc.
Mackenzie Davidson. a well-known
~ophthalmic surgeon of this city. has
just invented an apparatus which will
operations. and especially where the
be Of incalculab BILE benefit in surgical
eye is the organ to be operated on. BY
the apparatus the length of a fragment
imoedded In any part of the flesh can
be correctly estimated. it's exact posi-
ton outlined and the depth Of each
extremity correctly determined
The X rays. of course, are of much
value, but surgeons ave come to real
lie they are not quite" so successful in
the diagnosis of foreign substances in
hte human body as was at first sup
posed. The visible effect OF the X rays
Is only a shadow. often ~treacherous and
unreliable. 1t Is not enough for the
surgeons To have a fine 'sciagraph"
indicating that foreign substances exist
I'm the m frame. In order to OPP
crate with complete confidence, one re-
quires to know the size OF the object.
its position n depth from the skin at
any point selected. He needs, i'm fact,
a simple method of exact measurement
and localization.
An opportunity was afforded by Mr..
Davidson to see him uses his apparatus
On two patients the other day. one of
the patients mad been suffering from
an infiamed eye some our months, and
was In danger of losing this organ al
together. Whether a foreign body was
lodged i'm the eye or not was unknown,
and even If this had been ascertained.
the surgeon would not have been in IA
position to operate. knowing neither
where the object lay nor its size and
IIfa la.t In 40 IaHr - .I..
new method of localiZation. and he had
come to undergo MIR. Davidson's pro
cess. The result was that the foreign
body was detected, its exact position
I'm the eye given and the precise depth
at which each of its extremities could
be reached by the operator clearly fore
told. A few days afterward the body
was removed by a surgeon, thus prov
ing the correctness of Mr.. Davidson's
methods. Before this invention the
Roentgen hays had had no place in
ophthalmic work. because no surgeon
would care to operate on the eye with
only an ordinary X-ray picture to guide
him. Mr.. Davidson has already saved
numerous eyes which must otherwise
have been lost. and his method of local
iZation will enable hundreds of eyes To
be saved in the future. OF course the
method lis applicable to all parts of the
body, but it's widest field will be i'm the
direction of ophthalmic work, for the
operator has only To follow Mr.. David
sons methods To be able to diagnose
correctly. to operate successfully and
TO remove the offending substances
with certainty and directness.
Mr.. Davidson's method is to take two
Roentgen photographs on the same
plate-or. In some instances las when 1t
IL desired TO locate a fragment in the
eye) on two separate plates. For each
picture the vacuum tube is shifted into
a different position, so that the result
ing picture shows double images, by
means of which the exact position and
depth Of the bodies to be extracted can
be determined. The apparatus for TAX
ing the photographs has a horizontal
bar, on which is a scale graduated in
millimeters, and on this bar the Crookes
tube is made TO slide up and down. The
patient places the part of his body to
be photographer" on a plate. situated
Immediately under the bar. and when
the tube is shifted for the second eX-
posure its position on the scale is care
fully noted. The plate is developed in
the usual way, and, as before mention
ed. shows everything double.
From the measurements made before
exposing the plates one could, by means
OF a mathematical formulate, or geomet-
rical drawing to "A scale. arrive at a
correct knowledge Of he position of
the foreign body. But this YOU be
a ediou and difficult process. inyolv-
ms long abstruse calculations. MIR.
Davidson's method of localiZation is
simplicity itself. The apparatus con-
tains a horizontal stage and a horizon
tai bar with a scale on il. The mega
tive with the double image upon il il
placed upon the horizontal stage and is
so adjusted that il Is now i'm exactly
the same conditions as II occupied when
being taken. All that is now required
is to trace the path of the Y rays which
produced the negative, and this is how
IL is done:
The distance n each side Of the mid
die point of the scale to which the tube
was displaced being known. two fine
white silk threads are placed at these
spots. Small weights are attached to
one of the ends of each thread. while
the other Is threaded into a fine needle,
which il weighted by being fixed into
small ead weights. i'm shape resembling
a mouse. ON the negative las before
stated) two images OF the foreign body
whatever II may be-are seen. If one
OF the threads Is placed on the point of
the needle in n shadow correctly II
will indicate the path Of the y "a
that produced this shadow. Similarly.
IL the other thread be placed on the
corresponding point of the other shad-
ow, IL follows that the position actually
occupied by the point of the needle in
the flesh OF the patient is precisely
where the two threads cross. BY means
now of a pair of compasses and an up
right square the operator can at once
give the surgeon the exact depth at
which zach of the extremities of the
foreign body can be reached by a YER
teal p~uncture.
Although but a few weeks old. this
discovery Of Mr.. Davidson's has had
great results. and by its application
many patients have regained the use
Of members which they might other
wise rave lost. To ophthalmic SUR
geons. especially. h discovery is Of
great Importance. for they can now To-
cslize foreign bodies In h e eve and
extract them with every certainty Of
success.
Representatives OF the London county
council and various cities on the coasts
OF England and Wales called on the To-
cal government board the other day to
ask for an alteration of the law relat-
ing TO the culture Of oysters and other