349

FLUORINE IN THE DIET AS A FACTOR IN THEPREVENTION OF DENTAL CARIES

By GILBERT J. PARFITT, F.D.S., R.C.S., M.R.C.S., L.R.C.P.British Postgraduate /Medical Federation, Institute of Dental Surgery

Caries can be controlled by the early treatmentof the carious lesion, by alteration of conditionsupon the tooth surface and by dietary meansduring the period of tooth formation.The incidence of dental caries is influenced by

a large number of factors. After the teeth haveerupted, local conditions on the surface of theteeth have the greatest influence, but tooth struc-ture is of considerable importance. Teeth thathave a rough surface texture are more readilyattacked by caries than those presenting a smoothsurface,1, 2 and it has been demonstrated by oneobserver that a rough surface texture of the enamel.is associated with hypocalcification of the deeperlayers of the enamel beneath.3 4 Both conditionsare consideied to be the result of metabolic dis-turbance, usually of dietary origin, during toothformation.

Effect of Calcium and Phosphorus in DietTooth structure is sensitive to metabolic dis-

turbance during tooth formation5 and has beenshown to be affected in animals by dietary means,particularly by alteration of the calcium,phosphorus and vitamin D levels of the diet.Toverud6 carried out a carefully controlled

study in Norway and showed that dental cariescould be reduced in children by dietary controlcarried out over the entire period of tooth forma-tion. This necessitated diet control during theante-natal and post-natal periods up to the timeof tooth eruption.Under the age of five years, the clinical difference

between the dental caries incidence of the con-trolled and uncontrolled groups was remarkable.However, the percentage difference diminishedwith age, as both groups above a certain age showeda similar rate of caries incidence, but in each agegroup those who had undergone diet control hadless dental caries.

Effect of Fluorine in DietEpidemiological studies demonstrate that the

ingestion of a trace of fluorine during tooth for-mation also affects the tooth structure and lowersthe incidence of dental caries. The addition of

fluorine to the diet might, therefore, be a possiblemeans of mass caries control.The first effect of fluorine upon the teeth to be

reported was a white mottling or a brown stainingand pitting of the enamel surface.7 This conditionwas noticed in a large percentage of teeth of peopleliving in certain well-defined localities. Onehundred and forty of such endemic areas werereported in the U.S.A., and Ainsworth,8 in thiscountry, reported upon the mottled teeth foundin the inhabitants of Maldon in Essex. Manyother reports of such areas have come from variousparts of the world.

Ainsworth reported that all the cases showingmottling or staining of the teeth came from withinthree miles of Maldon and that this disfigurementwas not seen in individuals born outside the areaand moving into Maldon above the age of eightyears, the incidence of mottling decreasing rapidlywhen the move occurred above the age of threeyears. He noted that the brown stain firstappeared on the most prorhinent part of theerupted tooth and was then followed by stainingof the most prominent part of the next tooth tobe exposed in the mouth. This suggested anoutside influence or origin of the stain, such asatmosphere or water.The possible causes of such a clinical condition

were considered and the most likely was thoughtto be the presence of some substance in the drink-ing water. The water of the Maldon district wasanalysed and the presence of a higher-than-averageconcentration of fluorine was found.

Similar observations were made in America9and, in a survey of a large number of such areas,no differences other than the fluorine content ofthe water supply could be discovered.

In 1928 Ainsworth also reported a lower dentalcaries experience in both deciduous and per-manent teeth of the Maldon children, althoughthe deciduous teeth showed no evidence of mott-ling. Black in i9i610 and McKay in 1929,11 ayear after Ainsworth's report, noted a decreasedamount of caries in other endemic areas.

Following these reports, surveys were carriedout to ascertain whether a correlation existed

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350 POSTGRADUATE MEDICAL JOURNAL July I951

between the dental caries experience and thefluorine content of drinking water, and to whatextent fluorine was present in foods and publicwater supplies.Natural Occurrence of Fluorine

Fluorine is widely distributed in nature, beingpresent in measurable amounts in almost everyarticle of diet12',3 and in many water supplies.Surface water contains only a trace of fluorineand most public water supplies utilizing surfacewater contain less than 0.2 parts per million(p.p.m.) of fluorine. A number of public supplies,however, obtain water from boreholes which maycontain an appreciable amount of fluorine shouldfluorine be present in the water-bearing strata.

Fluorine occurs in rocks as fluorspar andapatite and is present in the phosphatic beds andclays which occur in many parts of England.14In these areas, if the drinking water is obtainedfrom boreholes, some of the supplies contain asmuch as 6 p.p.m. of fluorine, as in the Maldondistrict. Public water supplies in England withabove I.0 p.p.m. of fluorine include Chelmsford,Colchester, Maldon, Slough, South Shields andWest Hartlepool, but although these and manyboreholes in Essex and a few isolated supplies con-tain appreciable amounts of fluorine, the majorityof drinking waters in this country contain lessthan 0.2 p.p.mAmount of Fluorine IngestedAn average mixed diet contains from 0.2 to

0.3 p.p.m. of fluorine, which supplies between0.2 and 0.5 mg. of fluorine per day,12, 18 apart fromthat taken in the drinking water. Some articles offood contain above I.o p.p.m. of fluorine, notablycereals, flour and some vegetables; fish maycontain up to as much as 15 p.p.m.The average daily water consumption is be-

tween 2 and 24 pints, but the amount taken byindividuals varies considerably.6, 16 If the fluorinecontent of the water is I.0 p.p.m., i.5 mg. offluorine may be ingested by this means, in additionto that contained in the solid diet. A total amountof 0.8 mg. or more of fluorine per day would beingested by children drinking a water containing0.2 p.p.m., whereas more than double this amountmight be ingested,by those living in a high fluorinearea where the water contains from I.o to 1.5p.p.m. of fluorine.

Absorption of FluorineFluorine in the drinking water is absorbed'l

from the gut more readily than fluorine containedin the food; 80% of water-borne fluorine isassimilated,17 whereas only 60% of fluorine infood is absorbed,l2 the remainder being excreted

in the faeces. The fluorine which becomesabsorbed is excreted in the urine or sweat.

Absorption of fluorine is influenced by thepresence of other substances in the gut, in par-ticular calcium, which when present in sufficientamounts considerably decreases its absorption. Inthis respect it is of interest to note that, duringthe first years of life, when tooth formation isactive, the diet mainly consists of milk, which notonly has a low fluorine content (cow's milk con-taining only 0.07 to 0.22 p.p.m.), but containsa considerable amount of calcium and replaces theconsumption of water. A certain percentage offluorine, however, is even absorbed from calciumfluoride.

Proprietary brands of baby food may containmore fluorine than raw cow's milk, as they aremade up with water which, in some districts, hasa high fluorine content, but the amount of calciumin the diet is high and is admixed with thefluorine-bearing water.At this important period, therefore, not only is

the fluorine content of the diet low, but absorptionis hindered.

Fluorine BalanceIn a study of the fluorine content of the urine,

it was found that, in general, the fluorine contentof the urine was similar to that of the drinkingwater,7. slightly above when the content of thedrinking water was below 0.3 p.p.m. and slightlybelow when the water content was above 1.2p.p.m., but this did not necessarily indicate aretention of fluorine by the body. McClurereported that the amount of fluorine absorbedfrom food, in the various groups studied, wasremarkably constant.The fluorine concentration of the blood is also

proportional to the fluorine content of the drinkingwater.l8 The average fluorine concentration inthe blood of a group of individuals was .o014p.p.m. when the drinking water contained 1.12p.p.m. of fluorine. The highest blood concentra-tion found was o.I p.p.m., one member of eachgroup having this level, which suggested that,although the average blood level of fluorine wasraised by'taking a high fluorine content water, aconcentration of i. I p.p.m. did not produceexcessive blood levels.

Elimination of fluorine from the body is prac-tically complete if the ingestion is not above 4.0to 5.0 mg. per day.'2 No toxic accumulation takesplace below this level, but if water containingbetween I.5 to 3.0 p.p.m. of fluorine is ingestedduring the period of tooth formation, mottlingand staining in a certain percentage of the teeth isproduced, but no bone lesions occur.

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July I951 PARFITT: Fluorine in the Diet 351

ToxicityBone lesions have been described in a few

members of a community whose water supplycontained 6.0 p.p.m. fluorine,19 but many othercommunities drink water containing a higherfluorine content and no bone lesions have beenreported amongst them. Several reports suggestthat well-nourished individuals are able to takegreater amounts of fluorine without showing signsof fluorosis of either teeth or bones.20 It is thoughtthat an ample supply of vitamin C fs of particularimportance. The individuals in which the bonelesions were described were particularly illnourished.19

Ainsworth reported that the eruption of theteeth was apparently delayed in children residingin Maldon,8 and in Colorado Springs21 it is statedthat the late eruption found in that communitymight be associated with the high fluorine contentof the water supply (2.6 p.p.m.); no alterationin the dates of eruption were observed in com-munities using supplies containing under 2.0p.p.m. of fluorine.The toxic effects of substances such as fluorine

depend upon the quantity ingested, the length ofexposure, its elimination from the body and thethe tissue tolerance. Cryolite (Na3AlF6) workersmay absorb up to 30 mg. fluorine daily, the con-centration in the urine reaching up to 43 p.p.m.12Retention of fluorine occurs in the bones of suchindividuals. Excessive concentrations of fluorinein the urine may be demonstrated for as long asseven years after cessation of exposure to cryolitedust.

Fluorine in TeethSeveral investigators have analysed teeth for

their fluorine content.5 Less fluorine was foundin the enamel- than in the dentine, but in eachtissue the amount was related to the fluorinecontent of the water supply.22 When the fluorineconcentration of the drinking water was between0.2 to 0.3 p.p.m. the enamel was found to containo.oI per cent. fluorine and the dentine 0.023 percent., when the water content was I.o to I.i p.p.m.the enamel contained 0.013 per cent. and the den-tine 0.038 per cent., and when the water contentwas 7.6 p.p.m. the enamel contained o.o6 per cent.and the dentine o.I2 per cent. No more fluorinewas found in non-carious than in carious teethfrom the same individual.23

Epidemiological StudiesReduction in caries incidenceAs early as I916, Black'° observed a lowered

caries incidence in areas of endemic fluorosis,and in 1928 Ainsworth7 found that only 7.9 percent. of the permanent teeth of Maldon children

were carious, whereas the average caries incidenceof the permanent teeth of similar groups of childrenin other parts of the country was 13.1 per cent.Caries of the deciduous teeth was also reduced,12.8 per cent. being carious in the Maldon child-rei as compared with the average of 43 per cent.for the whole country. This reduction in dentalcaries, peculiar to the Maldon district, wasattributed to the same cause as that which pro-duced mottling and staining of the teeth.

Dean, in 1938,24 carried out a dental survey ofschool children in two towns in the United Statesand reported that the children of Galesburg,where the water supply contained i.8 p.p.m. offluorine, had a dental caries incidence of one-thirdof that of the children of Quincey, where thewater supply was fluorine-free. A wider surveywas then carried out in 21 cities, 7,0oo childrenbeing examined in all.26 The data showed aremarkably consistent relationship between thefluorine content of the drinking water and thedental caries experience; caries being consistentlyless with increasing amounts of fluorine in thewater supply.The incidence and severity of mottling of the

teeth was also found to be increased with increas-ing fluorine content of the water, but the appear-ance of dental fluorosis was not essential to thelessened dental caries experience, as both themottled and unaffected teeth became equallycarious. A full analysis of the water supplies ofthese communities was carried out, but no cor-relation was found to exist between the incidenceof dental caries and the hardness of the water orthe presence in the water of any substance otherthan fluorine.A low dental caries experience has been reported

from many areas where the fluorine content of thedrinking water is high. In this country, Weavercarried out a dental and nutritional survey of thechildren of North and South Shields,26 two townssimilar in many respects, but differing in thefluorine content of the drinking water. TheSouth Shields water is drawn from boreholes inmagnesium limestone and was reported to contain,on an average, between 1.2 and I.8 p.p.m. offluorine, whereas the fluorine content of NorthShields water supply was 0.25 p.p.m. In eachtown 500 children aged five years and a similarnumber aged twelve years were examined. Thecaries experience of both the deciduous and per-manent teeth was. found to be between 50 to 60per cent. lower in South Shields, which is in closeagreement with the findings of.Dean for thisparticular level of fluorine in the drinking water.Weaver found no evidence of delay in the eruptionof the teeth nor any inter-relationship between theincidence of caries, mottling of the teeth and

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nutritional condition. Expressing the differencein caries experience, between the two groups, asa percentage might be misleading, and it was sug-gested that a truer perspective might be given byexpressing the lowered caries experience as a delayin the onset of dental caries. He found that atfifteen years of age the children in South Shielflshad the same average amount of caries as foundin the children of North Shields at 12 years ofage and that this, therefore, could be expressed asa delay of dental caries of three years.

In a survey carried out six years later, Weaver27found the difference in the dental caries experienceof the two groups was not so great as in the firstsurvey and attributed the change to an alterationin diet.Weaver also examined a number of adults in

North and South Shields and, although therewas a difference in the dental caries incidencebetween the two groups, caries increased year byyear at a similar rate, the difference being equiva-lent to a postponement of caries of about fiveyears.28 He also examined children and adultsin West Hartlepool,27 where the water contained2.0 p.p.m. of fluorine, and found that each agegroup showed a lower caries incidence than com-parable groups in South Shields where the watersupply contained 1.6 p.p.m. of fluorine. Althoughthe dental caries was considerably reduced inWest Hartlepool, the amount of mottling of theteeth of the adults was severe.From these surveys it became clear that the

margin between beneficial amounts of fluorine inthe drinking water and amounts that producemottling of the enamel is narrow, and there is alimit to the reduction in caries that can be obtainedon account of the adverse effects on the teethfollowing the ingestion of the higher concentrationsof fluorine.

Hodge29 analysed the data collected by Dean inhis survey of 21 cities and found that, by plottingthe incidence of mottling of the teeth and of cariesagainst the fluorine content of the drinking waterupon a logarithmic scale, the data fell on twostraight lines. The line representing the decreasein caries crossed the line representing the in-cidence of mottling at, or above, the level of Ip.p.m. of fluorine and this point of intersectionmight be called the point of minimal caries withminimal mottling of the enamel.

Mottling of the enamel associated with a fluorinecontent of the drinking water below I.5 p.p.m.is so mild as to be unnoticed unless the teeth arespecifically examined for the condition, and onlyabove this point is the condition unsightly or theincidence high. At the level of i p.p.m. of fluorinethere was no indication that the occasional appear-ance of white flecks on the enamel surface is, in

fact, associated with the presence of fluorine in thedrinking water.

This analysis, therefore, demonstrated that abeneficial reduction in dental caries could beproduced with little or no injury to the enamel.

Ingestion ofFluorine during Tooth Formation

Investigations have been carried out to findat what age ingestion of fluorine produces an effectupon the teeth. For this purpose an examinationwas made of families that had migrated intohigh-fluorine areas30 and of children from com-munities whose water supply had been changed toa higher fluorine level.3' 32

From these studies it was found that the mostsusceptible period was from birth up to the age ofsix or eight years. During this period ingestion offluorine in the drinking water could affect theteeth either as a fluorosis or as a beneficialreduction in dental caries.The extent to which caries was reduced was

shown, therefore, to be dependent upon the lengthof stay and the age at the time or arrival in thehigh-fluorine area. If the child was resident foronly some of these years, certain of the teeth onlywere affected and reduction in dental caries wasnot so marked; the teeth affected being thoseundergoing a particular stage of calcification at thetime. The full effect was obtained only by theingestion of fluorine continuously over the wholeperiod from birth to the time of eruption of theteeth.

Arnold, however, found no change in dentalcaries experience in a small group of children whofor four years had consumed water, the fluorinecontent of which had been changed from o.Ito 0.7 p.p.m.

Russell33 also reported upon the dental con-dition of a group of children in the town of Mit-chell, whose water supply had been accidentallyfluorinated over a period of eighteen months. Thesurvey was carried out between nine and ten yearsafter exposure. During the eighteen months inquestion the fluorine content was probably main-tained at a level of I.o p.p.m. for a period of sixmonths and at 2.8 p.p.m. for five months; ioper cent. of the children showed a mild degree ofmottling, but no change in the dental cariesexperiencawas observed. The caries rate of theMitchell and of comparative groups of childrenrose continuously with age. Had there been anymarked inhibitory effect, the caries incidencecurves for the Mitchell children would havedeviated at certain ages, but they did not, whichdemonstrated that no alteration in the cariesincidence had occurred and no beneficial effecthad followed this temporary fluorination of thewater supply.

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July 1951 PARFITT: Fluorine in the Diet 353

Ingestion of Fluorine after Tooth FormationIt is generally reported that a reduction in

dental caries is not produced if the ingestion offluorine occurs above the age of six to eight years.Deatherage,4 however, reported a slightly loweredcaries experience in a group of 286 Servicemenwho had lived in high-fluorine areas for varyinglengths of time after their teeth had erupted, andthis suggested that the benefit is not entirelylimited to the pre-eruptive period. A 30 to 40per cent. reduction in dental caries incidence hasbeen claimed following the topical application ofa 2 per cent. aqueous solution of sodium fluorideto the surfaces of the. teeth soon after theireruption.Reduction in Dental Caries in AdultPopulation

Reports of the dental condition of adults whohave spent their entire lives in a high-fluorinearea show that the reduction in dental caries,so clearly demonstrated in children of school age,is continued to a certain degree into adult life.Arnold32 reports that fewer teeth are missing inadults living in Courtland and Bartlett, where thewater contains 5 p.p.m. and 8 p.p.m. fluorine,than in similar individuals living in fluorine-freeareas, and Weaver demonstrated a difference inthe incidence of caries in adults in North andSouth Shields which was equivalent to apostponement of five years.A survey in this country of three high- and three

similar low-fluorine areas35 demonstrated a dif-ference in caries experience of adults to be equiva-lent to a delay of ten years. A reduction in carieswas observed in children under the age of fiveyears. A very considerable reduction in dentalcaries extending throughout childhood and intoadult life appears, therefore, to follow the ingestionof fluorine-bearing water during the period oftooth formation from birth to six or eight yearsof age.Fluoridation of Public Water SuppliesAs many public water supplies contain less

than o.25 p.p.m. of fluorine, the possibility ofadding fluorides to the water to maintain the levelat, or near, I.0 p.p.m. has been considered, andin the United States and Canada four experimentalschemes have been in operation for three or fouryears.36 Preliminary reports show between 25per cent. and 45 per cent. reduction of caries indeciduous teeth and between 20 per cent. and30 per cent. in permanent teeth.The full effect of introducing fluorine into the

water supply cannot be assessed in less than 15years, by which time children born in the areawill have reached an age when a number of per-

manent teeth have erupted and have been exposedto the possibility of carious attack.A number of local authorities in the United

States have considered it unnecessary to await theresults of these experiments, and 70 cities arealready adding fluorides to their water suppliesand Ioo others are preparing to do so. Thevarious methods and the cost of water fluoridationhas been described by Bull.37

Administration of Fluoride in TabletsAlthough fluorine is absorbed appreciably less

from food than from water, there is some absorp-tion of fluorine from bone meal, cryolite andcalcium fluoride in the gut,16 and it has beensuggested that, in order to administer the necessaryamount of fluorine to children during the periodof tooth formation, tablets containing a fluorideshould be taken by the individual instead of sub-jecting the entire community to a water containinga high-fluorine content. Strean and Beaudet38investigated the effectiveness of fluoride-contain-ing tablets in reducing dental caries and claimedsome success, but other investigators have foundno reduction in dental caries following their use.This method of giving fluorine, therefore, is stillin the experimental stage, but has the disadvantagethat reliance has to be placed on the patient totake the prescribed number of tablets over aconsiderable length of time.

Laboratory Investigation of Fluorine Contentof TeethThe clinical evidence that the fluorine present

in the dentine and enamel is derived from systemicingestion during the period of tooth formation isconfirmed by animal experiments and by the factthat unerupted teeth show evidence of fluorosis.

Administration of sodium fluoride to rats byinjection demonstrated that a high fluorine intakeaffects the odontoblast cells, the formation of thedentine matrix, and also the calcification of theenamel and dentine. Such effects were consider-ably greater when the animals were placed ona low calcium, rachitic diet and, in addition, anuncalcified zone appeared in the tooth substancecorresponding in position to the line of develop-ment at the time of injection.39 This particularreaction did not take place when the animals werefed on a normal diet or on a high calcium rachiticdiet.

Analyses of enamel and dentine have demon-strated that the teeth of individuals born in high-fluorine areas contain considerable amounts offluorine. Electron microscopy of such teeth showthat the etched surface of the dentine and enamelhave a finer structure than is normally seen,40and electron diffraction and X-ray diffraction

D

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354 POSTGRADUATE MEDICAL JOURNAL July 1951

studies show that the fluorine present in the teethis in the form of a fluorapatite.Mechanism of Caries Reduction by Fluorine

There are several possible mechanisms by whichthe ingestion of fluorine may reduce dental caries.It may interfere with the acid-producing mech-anisms of the oral bacteria or increase the resistanceof the tooth structure to acid attack, or interferewith proteolysis.

Sodium fluoride affects the metabolism of orallactobacilli41 and inhibits acid production fromglucose in concentrations from I.o to Ioo p.p.m.However, the actual number and growth of thelactobacilli is not greatly affected. Salivary lacto-bacillus counts are found to be only slightly lowerin high-fluorine areas.42, 43The presence of fluorine ions inhibits cellular

oxidation and also inhibits carbohydrate fermenta-tion by inactivation of enolase.44 Fluorine entersinto complex compounds with calcium, mag-nesium, manganese and iron and in concentrationsof ioo p.p.m. many of these metals present in themolecules of enzymes or in the substrate becomebound to fluorine and a number of enzymesystems necessary to bacterial activity are whollyor partially inhibited.

Enolase is the most sensitive enzyme and theonly one likely to be affected by the concentrationsof fluorine found in the mouth. It is thoughtthat the presence of fluorine in the oral cavity inconcentrations of I.o p.p.m. introduced in foodand water is unlikely.to have any marked effect onthe carious process.The fluorine content of the saliva is increased

by ingestion of fluorine in the drinking water, 4p.p.m. giving rise to an average salivary level ofo.I6 p.p.m. of fluorine.46 This concentration isnot sufficient to interfere with bacterial activityand clinically it was found that the concentrationof fluorine in the saliva had no relation to dentalcaries experience. A concentration of fluorine isfound to occur beneath the enamel surface, andHodge and Sognnaes46 suggested that the fluorinebound in combination with enamel may giverelatively high local concentrations of fluorine.This might inhibit the bacterial activity or theenzyme processes which are believed to dissolvethe protein and calcified material of the toothsubstance, but presumably the combined fluorinewould have to be released before it could be madeavailable and some destruction of the tooth sub-stance would necessarily have already occurred.Fluorine may combine with the organic material

of the tooth substance and this might profoundlyaffect proteolysis.A further explanation of the mechanism of the

reduction of dental caries is that the tooth sub-stance is rendered less readily soluble in acids bythe presence of fluorine. Should dental caries,therefore, be intimately connected with acid des-truction of the tooth substance, the presence ofthe less readily soluble fluorapatite might explainthe lowered caries incidence. Clinical findingspoint to the presence of fluorine in the toothsubstance itself as being the important factor andthe latter explanation is possibly the more tenable.

Partial Control of Dental Caries by Ingestionof Fluorine

Fluorine is not present in foods in sufficientamounts to give any beneficial effect from ingestionand the few articles of diet which contain largequantities of fluorine cannot be taken to theexclusion of other foods. Addition of fluorine tothe common food substances is not practicableas the dosage is not under control, for varyingamounts of the food might be consumed by dif-ferent individuals; nor would the food substancenecessarily reach those most likely to derivebenefit from it. But the presence of naturallyoccurring fluorine in the. drinking water in con-centrations of I.o to 1.2 p.p.m. has not only beendemonstrated as harmless but as causing a con-siderable reduction in dental caries. The artificialintroductionof fluorine into the drinking waterby addition of fluorides, as carried out in so manydistricts in the United States of America, wouldappear to be a most valuable measure in the controlof dental caries.

SummaryThe natural occurrence of fluorine, the amounts

ingested in food and water, its absorption andexcretion is outlined.

Epidemiological studies upon dental caries in-cidence of communities using water suppliescontaining various amounts of fluorine aredescribed.A considerable reduction in dental caries-

experience with increasing amounts of fluorinepresent in the drinking water has been found,together with a rise in the incidence of mottledteeth, the earliest sign of a fluorosis. The possiblemechanisms of the reduction of dental caries bythe ingestion of fluorine and of mass control ofdental caries are discussed.

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4MELLANBY, M. (I937), Brit. Dent. J., 62, I7.bLEICESTER, H. M. (1949), 'Biochemistry of the Teeth,' pub.

by Henry Kimpton, London.'TOVERUD, G. (1949), Brit. Dent. J., 86, 191.

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(aries and Fluorine,' 53-73.

WOMEN IN MEDICINE: THE EARLY YEARSBy MAY THORNE, O.B.E., M.D., F.R.C.S.I., L.S.A.

A hundred years ago a stirring began to be feltby a few women both here and in America thatthey should be able to prepare themselves to enterthe medical profession. Elizabeth Blackwell wasthe first woman in America who, about i850,made up her mind to study medicine. She hadno idea at that time of the difficulties that stoodbetween her and qualification, but by dint ofattending a few lectures here and there, by makinguse of every scrap of experience, by reading andby the help of a few physicians who sympathizedwith her in her ambition, she, after some years ofhard struggle and disappointing work, managedto present herself for examination at the Universityof Geneva in the State of New York, passed andbecame a qualified physician.

In England a few years later Elizabeth Garretthad similar ambitions. She met with similartrying experiences, but she, too, persevered in anindomitable way. She had the friendship of someof the leading medical men, who gave her sym-

pathy, though they could give her little help;but she got a little teaching and experience hereand there and made the best possible use of it.After some years she learned that the Society ofApothecaries of London admitted, to their licenceto practise medicine, students who held thecertificate of a practical apothecary. She becameapprenticed and subsequently qualified as anapothecary, and in I865 applied for admission topresent herself at the final examination. She wasadmitted to the examination, passed and was thusthe first woman in England legally qualified topractise as a physician of medicine. The Societywas apparently horrified at what it had done, andat once took steps to alter its regulations foradmission to the examination, by making a rulethat in future, certificates of instruction from arecognized medical school must be presented byall candidates for the final examination. Thisregulation prevented any other woman from pre-senting herself for the final examination.

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