ThefirstexperimentsonthebiologicalpropertiesofradiumweresuccessfullymadeinFrancewithsamplesfromourlaboratory,whilemyhusbandwasliving.Theresultswere,atonce,encouraging,sothatthenewbranchofmedicalscience,calledradiumtherapy(inFrance,Curietherapy),developedrapidly,firstinFranceandlaterinothercountries.Tosupplytheradiumwantedforthispurpose,aradium-producingindustrywasestablished.ThefirstplantwascreatedinFranceandworkedverysuccessfully,butafterwardsmanufactureswerefoundedinothercountries,themostimportantofwhicharenowinAmerica,wheregreatquantitiesofradiumore,named"carnotite,"areavailable.Theradiumtherapyandtheradiumproductiondevelopedconjointly,andtheresultsweremoreandmoreimportant,forthetreatmentofseveraldiseases,andparticularlyofcancer.Asaconsequenceofthis,severalinstituteshavebeenfounded,inthelargecities,fortheapplicationofthenewtherapy.Someoftheseinstitutesownseveralgrammesofradium,thecommercialpriceofthegrammebeingnowabout$,,thecostofproductiondependingontheverysmallproportionofradiumintheore.
ItmaybeeasilyunderstoodhowdeeplyIappreciatedtheprivilegeofrealizingthatourdiscoveryhadbecomeabenefittomankind,notonlythroughitsgreatscientificimportance,butalsobyitspowerofefficientactionagainsthumansufferingandterribledisease.Thiswasindeedasplendidrewardforouryearsofhardtoil.
Thesuccessofthetherapydepends,ofcourse,onthepreciseknowledgeofthequantityofradiumwhichisused,sothatthemeasurementsofradiumareasimportantforindustryandformedicineasforphysicochemicalresearch.
Consideringalltheseneeds,acommissionofscientificmenofdifferentcountrieswasformedwhoagreedtotakeasabaseaninternationalstandard,formedofacarefullyweighedquantityofpureradiumsalt.Secondarystandardswerethentobepreparedforeachcountry,andcomparedtothebasicstandardbymeansoftheirradiation.Iwasappointedtopreparetheprimarystandard.
Thiswasaverydelicateoperation,astheweightofthestandardsample,quitesmall(aboutmilligrammesofchloride),hadtobedeterminedwithgreatprecision.Iperformedthepreparationin.Thestandardisathinglasstube,ofafewcentimetersinlength,containingthepuresaltwhichwasusedforthedeterminationofatomicweight.ItwasacceptedbytheCommissionandisdepositedintheInternationalBureauofWeightsandMeasuresatSevres,nearParis.Severalsecondarystandards,comparedwiththeprimaryone,havebeenputintoservicebytheCommission.InFrancethecontrolofradiumtubes,bythemeasurementoftheirradiation,takesplaceinmylaboratory,whereanyonemaybringtheradiumtobetested;intheUnitedStatesthisisdoneintheBureauofStandards.