1995;126;1359-1367 J Am Dent Assoc

PH Jacobsohn and RJ Fedran X-ray and its introduction to dentistry

Making darkness visible: the discovery of

jada.ada.org ( this information is current as of August 29, 2008 ):The following resources related to this article are available online at 

http://jada.ada.org/cgi/content/abstract/126/10/1359in the online version of this article at:

including high-resolution figures, can be foundUpdated information and services

http://jada.ada.org/cgi/collection/imagingImaging   : subject collectionsThis article appears in the following

http://www.ada.org/prof/resources/pubs/jada/permissions.aspthis article in whole or in part can be found at:

of this article or about permission to reproducereprintsInformation about obtaining

© 2008 American Dental Association. The sponsor and its products are not endorsed by the ADA.

on August 29, 2008

jada.ada.orgD

ownloaded from

DarkinessVisible:

The Discovery of

X-ray and Its

1 .~~~~~~~1Introduction to

Dentistry

PETER H. JACOBSOHN, D.D.S.;ROBERT J. FEDRAN, R.T.R.

The first radiograph of humananatomy, 1895.

Nov. 8, 1895. Scientist WilhelmConrad Roentgen is at work in hislaboratory in the Bavarian city of

Wurzburg, testing the ability of cathoderays to penetrate a vacuum tube. He de-termines that the rays are too weak topermeate the glass. He is about to end

the experiment when he notices a faint glow rising from a papercoated with barium platinocyanide crystals-a glow that in-creases as he moves the paper closer to the tube and fades com-pletely when he turns off the tube's power supply. Elated andmystified, Roentgen realizes that he has stumbled across a formof energy that neither he nor, likely, the rest of humankind hasever before encountered: energy that is capable of penetratingsolid materials.lA He christens this alien energy "the X-ray" andunknowingly places the world on the threshold of atomicmedicine.

Roentgen's discovery of the X-ray has been ranked in impor-tance with the discovery and development of anesthesia byHorace Wells and William Morton, both dentists, and the discov-ery of microorganisms and their role in disease by the likes ofPasteur and Lister. Today's dentistry would be impossible lack-ing the benefits of Roentgen's scientific devotion-and the per-sistence of C. Edmund Kells, who took Roentgen's discovery andshaped it for use in dentistry. Other European and Amexican pi-oneers made contributions that furthered dental radiography.As dentistry observes the centenary of the X-ray's discovery, itseems fitting to review the lives and work of the men who hadsuch a great impact on how dentists practice today.

JADA, Vol. 126, October 1995 1359

on August 29, 2008

jada.ada.orgD

ownloaded from

_COUVE STODY

THE PATH OF A PIONEER:ROENTGEN'S CAREERAND GREATEST DISCOV-ERY

A nyone tracing thedetails of the X-ray's discoverycould well askwhether it was

brought about by the skill of thediscoverer or an accidental oc-currence.2 Now, 100 years afterthe historic event, we can con-clude that it was both the ge-nius of a scientific investigatorand the right set of circum-stances that introduced theworld to the science of atomicmedicine.

Born on the Lower Rhine andbrought up in the Netherlandsin the middle of the 19th cen-tury, Wilhelm Roentgen led theplacid life of a well-loved onlychild until his teens. At 16years of age, he was expelledfrom school for his involvementin a prank and for refusing todivulge the names of his accom-plices. This act would haunt hisacademic and professional ca-reer, because it barred his wayinto several universities andeventually thwarted some uni-versity appointments that hisinherent abilities otherwisemight have won for him.5

At last, however, he obtaineda long-sought university degreefrom the Polytechnic Institutein Zurich, despite corneal ulcersthat threatened his sight. Hewent on to add a doctorate inphysics to his list of credentials.Then began his struggle for auniversity position-a strugglebecause he was still dogged byhis lack of a high-school diplo-ma. One of his mentors at theinstitute at last helped Roent-gen secure a position as an as-sociate professor of physics atthe Imperial GermanUniversity in Strasbourg.

Roentgen, fi-nally havingsettled into em-ployment andhaving givenhis wife of fouryears some-thing of a per-manent home,turned his at-tention to hisresearch. Hisfavorite experi-ments involvedcrystals, whichhe felt hadmany as-yet-unrevealed in-teractions inother facets ofscience. Thisfascinationwould laterprove to be thecatalyst for hishistoric discov- William Conrac

as a scientist cery of the X- career.ray.3

Roentgen's research inphysics gained him a great dealof respect in the academic andscientific worlds, and he madehis way through several univer-sity positions of increasing re-sponsibility. In 1894, he was ap-pointed rector of the Universityof Wtirzburg, a position whosemany administrative dutiesforced him to set aside his re-search work until the autumnof 1895.7 That year foundphysicists throughout Europe-including Roentgen-conduct-ing research experiments in-volving gaseous dischargetubes. They were particularlyintrigued by the multicolor lu-minescence the tubes emittedwhen electrical current was ap-plied to them.The discovery. On a Friday

evening-Nov. 8, 1895-Roent-gen was conducting an experi-

d Roentgen succeeded dramaticallydespite an embattled academic

ment with a new kind of tube,called a Hittorf-Crookes tube, todetermine if the cathode raysproduced in it were strongenough to penetrate its glasswall. If they did penetrate theglass wall, a glow of coloredlight would appear around theoutside of the tube when therays encountered air. In an at-tempt to fully observe the phe-nomenon, he darkened the labo-ratory as much as possible. Tohelp his weakened eyes, he alsocovered the tube with blackcardboard to exclude any lightinterference.1 3-5 He appliedpower to the electrodes andcarefully observed the end ofthe tube but did not notice aglow around the outside of thetube. He concluded that cathoderays were not strong enough topenetrate glass.

As Roentgen was about to

1360 JADA, Vol. 126, October 1995

on August 29, 2008

jada.ada.orgD

ownloaded from

COVER STORY

turn off the power supply to thetube, he noticed a faint glow oflight being emitted by somecrystals ofbarium platino-cyanide applied to a piece ofpaper that lay on a table somedistance from the tube.13-5Knowing that cathode raystravel only about six to eightcentimeters from their source,he moved the crystals closer tothe tube and noticed that theglow grew brighter. As hemoved the crystals farther awayfrom the tube, they becamedimmer. When the current tothe tube was turned off, thebarium platinocyanide crystalsceased to glow.2'3 At this point,Roentgen realized that he wasobserving a new form of energy,a form of energy he knew noth-ing about that had the ability topenetrate solid material. He de-cided to call these rays "X" be-cause of their unknown nature.

In the weeks after his discov-ery, Roentgen was so mesmer-ized by this new form of energythat he totally immersed him-self in unleashing its properties.As he investigated the X-ray, hediscovered that these rays notonly caused crystals to fluorescebut also were capable of pene-trating solid objects. His experi-ments dealing with penetrationof objects included such materi-als as wood, paper, metals-andthe human body, thus openingthe door to the science of diag-nostic radiology.

The first radiographic imageofhuman anatomy ever re-corded was of the hand ofRoentgen's wife. This crude ra-diograph took 15 minutes to ex-pose, and when BerthaRoentgen saw the bones of herhand made visible on the photo-graphic plate, she said it creat-ed in her "a vague premonitionof death."2'3'5

Re oentgen carried outin silence his fever-ish work with themystery energy.Not even his wife

was aware of his historic discov-ery until after he was convincedthat indeed had found a newform of energy. Shortly afterthat November night, however,he did remark to a friend, "Ihave discovered something in-teresting, but I do not knowwhether or not my observationsare correct."

Publication and publicity.Forty days after the experimentin his Wurzburg laboratory,Roentgen announced to his col-leagues and the scientific com-munty the news ofhis discov-ery of this new form of energy.He submitted to the WurzburgPhysical-Medical Society apaper entitled "On a New Kindof Rays, A Preliminary Com-munication." This was the firstof the three classical communi-cations he would write about theX-ray-a cumulative 34 pages

on the characteristics of thisnew form of energy that wouldprove his genius as an inves-tigative scientist.2'3'5

Outside the scientific com-munity, news of Roentgen's dis-covery spread rapidly through-out the world. He found itdifficult to adjust to sensation-alism and publicity, havingnever wanted to be famous butsimply respected by his col-leagues. The fame and honorhis discovery won him led to anoffer of the position of professorand head of the PhysicalInstitute of the University ofMunich.23' He felt he could notrefuse this request, and in 1900,he and his wife made their finalmove.

Roentgen received many hon-ors-not the least ofwhich wasthe change in the name of hisdiscovery from "X-ray" to"Roentgen ray." He was recog-nized with awards from manynations, including, in 1901, thefirst Nobel Prize in physics.His modesty and his determina-

Roentgen's Wirzburg laboratory: an unassuming site for an amazingdiscovery.

JADA, Vol. 126, October 1995 1361

on August 29, 2008

jada.ada.orgD

ownloaded from

COVER STORY

tion not to reappersonal bene-fit from his dis-covery led himto decline sev-eral of thesetributes, and hedonated hisNobel Prizemoney to theUniversity ofWuirzburg andthe Germanwar effort. As adevoted scien-tist, Roentgenshowed his ap-preciation forthe honors be-stowed uponhim by givingto the world thegift of the X-rayto be used forthe good of hu-mankind; henever patented C. Edmund Kellit. ample of the in

Roentgendied in Munich in 1923.3 Hiswill requested that all his pa-pers dealing with his discoveryof X-ray be destroyed. A meticu-lous scientist to the end, heworried about what might hap-pen if his research notes weretaken out of context by othersnot as exacting as he.

A MACHINE TO TAKE PIC-TURES OF THE TEETH:KELLS AND THE X-RAY INDENTISTRY

I f Roentgen gave of hisscientific genius to bringthe X-ray to the world, C.Edmund Kells gave of hisingenuity, his diligence

and finally his physical healthto bring the X-ray to dentistry.A true dental pioneer, Kellsquickly grasped the potentialfor applying Roentgen's discov-ery to dentistry. Soon after

lIs with some of the female assistants he dared to employ-just one ex-inovations he made in dental practice.

Roentgen announced his discov-ery in December 1895, Kellswent to work to make the capa-bilities of the X-ray available tothe dental profession and there-by forever changed the waydentistry would be practiced.Laying the foundation for

a life of innovation. C. Ed-mund Kells, born in 1856, grewup in Union-occupied NewOrleans during the Civil War.6'7Although living and practicingin New Orleans duringReconstruction, Kells describedhimself in his biography as an"unreconstructed Johnny Reb."7Almost all of Kells' 72 yearswere spent in New Orleans, ex-cept when he went away toschool and during the Civil Warwhen his parents sent him tothe plantation home of friendsbecause "there was no telling

what those ferocious damnYankees might do."6

Kells' father was a prominentNew Orleans dentist, and afterhis high-school years Kells be-came an apprentice in his fa-ther's practice. The senior Dr.Kells was said to have had nosuperior as a prosthodontist,and in his practice he construct-ed many gold dentures.(Vulcanite was not yet avail-able.) One of young Edmund'sresponsibilities in that practicewas to electroplate his father'sdentures with gold. This wasthe beginning of a lifelong inter-est in electricity for the youngerKells.67

In 1876, Kells entered NewYork Dental College and gradu-ated in 1878 with a D.D.S. de-gree. While in dental school,Kells befriended several people

1362 JADA, Vol. 126, October 1995

on August 29, 2008

jada.ada.orgD

ownloaded from

COVER STORY

who worked in the Edison labo-ratory in nearby Menlo Park,N.J. He and his friends wouldoften "hang around" the Edisonlaboratory during their freetime. Here Kells observed someof the early work with electric-ity, including the research onthe first electric incandescentlamps.7The flowering of an active

mind. After finishing dentalschool, Kells returned to NewOrleans, where he would prac-tice dentistry for the next 50years. He developed one of themost extensive and lucrativepractices in the South.68 He alsobecame an inventor and innova-tor, patenting more than 30 in-ventions from 1880 through1922. His active mind found anoutlet in writing as well, and hepublished more than 200 arti-cles and two books on all as-pects of dentistry.

Mt /r any of the devicesKells conceivedwere electricallypowered; in fact,in 1886, he be-

came the first dentist to useelectric street current in hisdental office. A great deal of hiswork focused on improving thepractice of dentistry: the firstelectric mouth lamp, the firstelectric air compressor and thefirst completely electric dentalunit.679"0 However, his ingenu-ity was not totally confined toinnovation in his own field. Heheld patents on a thermostat,an electro-magnetic clutch andengine, an automobile jack, anautomatic window closer, a firealarm and extinguisher and anelevator starter and brake.67 Hedeveloped instruments and de-vices to be used in medicine andsurgery.

Of particular note was his in-

vention of a suction apparatusfor the irrigation and aspirationof fluids during surgery. Thesuction apparatus replaced theold technique of mopping thesurgical wound with sponges."Dr. Rudolph Matas ofNewOrleans, oneof the world'smosstytrenowned sur- 7 _7*°7geons, later s' grpaid tribute to -mIiKells": "The becamesuction appa-ratus is suffi- A0 uencarcient to im- ta denmortalize thename of Dr. C.Edmund bKells. He haswon the eter-nal gratitude of every workingsurgeon in the world."" Thisfruit of Kells' creativity becamea major advancement in mod-ern surgery.

Bringing the X-ray to den-tistry. The year 1896 saw Kells'greatest accomplishment: he be-came the first American dentistto take dental radiographs of aliving subject.89"4 He also wasthe first to exhibit a dental X-ray apparatus at a dental meet-ing, thereby opening new vistasfor the dental profession.'4

Soon after the announcementof the discovery of the X-ray byRoentgen in December 1895,many physics laboratories inthe country began their own ex-periments and demonstrations.Tulane University in NewOrleans was one of these.Professor Brown Ayres ofTulane University gave an earlyexhibition that Kells attended.7The following report of thatdemonstration appeared inKells' autobiography, "ThreeScore Years and Nine," pub-lished in 1926:

"Being interested, as I was,in electrics of all kinds, whatmore natural than that thisphenomenon should interest meextremely?" he wrote. "Well, itdid. Knowing Professor Ayresintimately, I suggested that I

would like amachine withwhich to try to

1896 saw take picturesatest ac~ of the teeth.

uent: he This aspect in-

hefirst terested himalso. With

LIeJIst to Professoriiradio-Ayres' aid I

was not longaUli:viug7 in getting a~~Ct. ~ Tesla Coil and

an improvedCrookes tube,

both having been specially de-signed for X-ray work.

"Just when I received thisoutfit and just when I took myfirst dental skiagraph [the term"skiagraph," from the Greekmeaning "shadow picture," wasin frequent use during Kells'day] I cannot say because Ihave no record of it. In the'Transactions of the SouthernDental Association' there is re-ported my X-ray clinic given inAsheville in July 1896 and I re-member full well that I had hadthe apparatus several monthsbefore giving this clinic and haddeveloped a method of takingdental skiagraphs. Thus I musthave begun this work in Aprilor May, 1896. I say 'developed amethod' because a method hadto be developed. No one hadtaken, as far as I know, anydental pictures of living sub-jects and the whole technic hadto be worked out by myself."7

Kells' initial radiographicwork was not done with pa-tients. His first subject-likelythe first person in America to

JADA, Vol. 126, October 1995 1363

on August 29, 2008

jada.ada.orgD

ownloaded from

COVER STORY

have a dental X-ray taken-washis female dental assistant. (Infact, Dr. Kells was the first den-tist in the South with thecourage to employ a youngwoman as an office assistant.Eventually, Kells would havefive female assistants in his of-fice.6"2'5) Kells also devised afilm holder made of vulcanite tohold the film in the patient'smouth, as well as equipment toaid in developing X-ray film.7

Kells became a vigorous pro-ponent of the use ofX-rays indental practice. In a presenta-tion before the National DentalAssociation in 1919, he stated,"The time is now here when it isfully recognized that the gener-al practitioner of dentistry isnot fully capable of renderinghis patients the very best ser-vices unless his equipment in-cludes an X-ray machine."He opposed the diagnosis of

dental disease by anyone otherthan dentists. In his day, it wascommon for physicians orroentgenolo-gists whowere lookingfor foci of in- W tfection to take adental X-rays, 1then refer the 'patient to adentist fordental extrac- Xtions without i aconsulting thedentist aboutdental pathol-ogy. Underthis system,many teethwere needless-ly extracted; this appalledKells, who felt that tooth con-servation was of the utmost im-portance. Kells took the positionthat while physicians androentgenologists should be able

Dr. Jacobsohn ishead, Dhiision of

Oral andMaxillofaclalSurgery, MarquetteUniversity School ofDentlstry,Mllwaukee 63233.He also Is prosident,American Academy

:Mr. Fedran Is a radi-

:ology teaching tech-*nologst and radiolo-

:gy clinic supervisor,:Marquette:Univeraity SchoIof

:Dentistry,Milwaukoe.

of the History of to take dentalDentlaty. Addra X-rays, theyreprint requesta to

Dr. Jacobsohn. were not al-ways able tocorrectly diag-

nose dental lesions depicted onthe film and, therefore, such di-agnosis should be made by adentist. Furthermore, he ad-vised that physicians refer suchpatients only to a dentist for di-agnosis and that dentists refuseto operate solely on a physi-cian's instruction.14

Kells' practice involved allaspects of dentistry, including

exodontia,which was a

:B prominent fea-ture of most

iiNt ~~dental prac-tices. In fact,the first dollar~fl he made in hispractice wasfor removing a

'~ tooth for a veryprominent

4. Confederategeneral. Kellsbecame an in-

tt,be..¢ -e, <.;novator in thefield of oralsurgery. After

introducing X-ray into his prac-tice, Kells began to X-ray all im-pacted and missing third mo-lars-"whereupon," he wrote,"the faulty methods formerlyused for their removal were

made manifest and I devisedthe operation of cutting thecrown in two and removing thetooth in sections."7

he costs of pio-T* *neering. Many pio-

neers who ventureinto uncharted wa-ters with their new

discoveries and innovations paya high price for their genius.Frequently, the danger of theirwork is not recognized immedi-ately or does not manifest itselfuntil years later. So it was withEdmund Kells.

The hazards of excessive ra-diation exposure not yet beingappreciated, Kells and otherswho used X-ray in the earlyyears had no qualms aboutusing a technique known as"setting the tube." Variations inthe quality and character of theX-ray were produced by a rheo-stat. The setting technique re-quired that the operator hold afluoroscope in one hand andplace the other hand betweenthe fluoroscope and the X-raytube. The rheostat on the X-raymachine was then adjusteduntil the bones of the hand ap-peared on the fluoroscopescreen and the operator wassatisfied that proper penetra-tion had been achieved. Everytime the operator "set the tube,"his hand was exposed to the X-ray for several seconds. The cu-mulative effects of this repeatedexposure were not recognizedfor a number of years.

In Kells' case, approximately12 years passed with no unto-ward effects. Eventually, how-ever-in about 1914-the fin-gers and back of his left handsuccumbed to radiation-inducedcancer. During the next 14years, Kells underwent morethan 40 operations, the last of

1364 JADA, Vol. 126, October 1995

on August 29, 2008

jada.ada.orgD

ownloaded from

COVER STOBY

which involved amputation ofhis arm. On May 7, 1928, unableto grapple any longer with thecancer that had claimed severalorgans and was causing him in-tense agony and suffering, Kellstook his own life in his dental of-fice.

Shortly before his death, hewrote his last article from a hos-pital bed in New York. In it werethe following remarks: "Do Imurmur at the rough deal the

fates have dealt me? No, Ican't do that. When I think ofthe thousands of suffering pa-tients who are benefited everyday by the use of X-ray I can-not complain. That a fewshould suffer for the benefitsof the millions, is a law of na-ture."'"

Kells died as he had livedwith concerns for the better-ment of his profession and thealleviation of suffering.

CONCLUSION

The discovery of X-ray 100years ago ranks high on the listof scientific discoveries, havinghad a major impact on the im-provement of health care deliv-ery. As a diagnostic tool, the X-ray plays a preeminent role inthe armamentarium of both thephysician and the dentist. Themen who pioneered the discov-ery of X-ray and its introductioninto medical and dental practice

JADA, Vol. 126, October 1995 1365

on August 29, 2008

jada.ada.orgD

ownloaded from

COVER STORY

are, in large part, responsiblefor the high quality of healthcare we enjoy today. Healthcare providers and the publicthey serve are forever indebt-ed to Roentgen, Kells and allthe others who worked-oftenat personal peril-to make itall possible. The occasion ofthis centennial year gives usan opportunity to rememberthem and to thank them. .The photographs on p. 1359-61 and p.

1367 are reprinted from Glasser PO.Wilhelm Conrad Rontgen, 1931.Heidelberg, Germany: Springer-Verlag.

1. Fortier AP, Glover JA Jr. Origins ofdental radiography. In: PW Goaz, SCWhite, eds. Oral radiology: principles andinterpretation. St. Louis: Mosby;1982:1-17.

2. Glasser 0. Wilhelm Conrad Roentgenand the early history of the Roentgen rays.Springfield, Ill.: Charles C Thomas;1934.

3. Grey V. Roentgen's revolution: the dis-covery of the X-ray. Toronto: Little,Brown;1973.

4. Bushong SC. Radiographic science fortechnologists. St. Louis:Mosby;1975.

5. Glasser 0. W.C. Roentgen and the dis-covery of the Roentgen rays. Amer JRoentgenol Radium Ther 1931;25(4):437-50.

6. Varnado MB. Dr. C. Edmund Kells: asI remember him. Bull Hist Dent1971;19(2):27-33.

7. Kells CE. Three score years and nine.Chicago:published by author, printed byDonnelly;1926.

8. Raper HR. Notes on the early historyof radiodontia. Oral Surg Oral Med OralPathol 1953;6:70-81.

9. Gardiner JF. C. Edmund Kells: NewOrleans' gift to dentistry. Bull Hist Dent1981;29(1):2-7.

10. Carr JO. The great radiology debate:the letters of C. Edmund Kells and HowaldR. Raper. Bull Hist Dent 1981;29(2):69-73.

11. Glenner R, Davis A, Barens S. The

American dentist. Missoula,Mont.:Pictorial Histories PublishingCompany; 1990.

12. Asbell MB. Dentistry: a historical per-spective. Bryn Mawr, Penn.:Dorrance;1988.

13. Langland OE, Fortier AP. The contri-bution of C. Edmund Kells: a bibliography.Bull Hist Dent 1971;19(2):34-43.

14. Kells CE. The X-ray in dental prac-tice. J Natl Dent Assoc 1920;7(3):241-72.

15. Franke OC. Wilhelm ConradRoentgen and other X-ray pioneers. BullHist Dent 1983;31(1):11-7.

16. Barr JH, Stephens RG. Pertinentbasic concepts and their applications inclinical practice. In: Dental radiology.Philadelphia: Saunders;1980:27-8.

17. Richman V. Twentieth century scien-tists. Vol. 1 A-E. Gale Research Inc.;1995.

18. Glenner RA. The dental office: a pic-torial history. Missoula, Mont.: PictorialHistories Publishing Company; 1984.

19. Glenner RA. Eighty years of dentalradiography. JADA 1975;90:549-63.20. Morton WJ. The X-ray and its appli-

cation in dentistry. Dent Cosmos1896;38:478-86.

:~~~ ~ ~ ~ ~ ~ W --a I:::--

W~~~ W FM4 kI u I lk"i~~:A *wt Most g-reat dis-

covenes anld.innova-tions, rarel isofonly

one person .ful responsible.While C. Edimund Kells prob-ablymade the getest con-tribution ointoducg theXray to dentistry, the effobrof several other pioneerssh6ould De recognized here.WMaLhof: the first in-

troral radiog .OttoWalkhoff, a dentist inBrunswick Germany, hadbeen working with a profes-sor of chemistry and physicsin research involvingt cathoderas when Roentgen's discov-ery was announced. Withintwo weeks of the announce-ment by Roentgen, Walkhoffcreated an intraoral radio-graph using a glass photo-graphic plat wrapped inblack paper and covered Wtha rubber dam. ;His exposuretimes were 25 minutes. His

radiograph may very well havebeen the: fiist intaoral radio-grapIKoenig:early dental ra-diographe. Wilhelm Koenig, aFIankfurt professor, wa alsoamog the very first to takedental X-rays. In February1896, he made a senres of 14dental radiograhs.

Harrison: a special vacu-um tube. In January 1896,Frank Harrison, a daetist inSheffield, England, reported tothe British MedicalAssociation that he had madea special vacuum tube fbr tak-ing dental radiographs.Harrison was a pioneer in an-other aspect of dental radiog-Iraphy as well: as early as July1896, he became one of thefi rst people to report radiationinjuries.1"8"19Morton: envisionindg the

possibiLlitlies. Wlllam J.Morton was the physician son

of Dr. William T.G. Morton ofBoston, who introducedt etheranesthesia in 1846. Morton,who had been exprmentingwith X-rays, presented hiswork to the New'YorkOdontolqgical SotyinApril 1896. He demonstratedfour intaoral ffilms takenfrom ofhuman skuls and afim plat ofthkeskull of aliving subject. His presenta-tion, which was later pub-lished in The Dental Cosmos,contained these prophetic re-marks:

"The applicatin ofX-raywill, I believe, greatly aid inthe ar of dental surgery.The radigraphs presented toyou here tonight are but afirst step toward takingTpie-tures of the,living teeth.They open out to your vew awondrous fleld for investiga-tion and study and diagnoss.Each errait fang is distinctly

1366 JADA, Vol. 126, October 1995

on August 29, 2008

jada.ada.orgD

ownloaded from