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.Furthermore, the appropriate dose for treating the children effec-tively could only be estimated for the serum produced at Koch s Institute,and these doses could not be applied either to sera coming from elsewherein the German Reich or from outside Germany.25The problems were now clearly posed, and Ehrlich aimed to solve themusing immunological theory based on chemical laws applied to medicineand supported by mathematics.Ehrlich received backing for his serologicalwork from the Prussian Ministry of Science and Education (Ministerialrat impreußischen Kultusministerium), thanks to the support of the prominent andpowerful Councillor, Friedrich Althoff (1839 1908).26 Previously, Ehrlichhad never received any official post in Koch s Institute, presumably becauseof his being Jewish,27 and when the control station for therapeutic sera(Controlstation für Heilsera) opened in the Institute in 1895, it was entrustedto Koch s assistants August Wassermann and Hermann Kossel and not toEhrlich, who was appointed deputy head of the department.28 But in 1896,at Althoff s instigation, Ehrlich became head of the new Institute for SerumResearch and Serum Testing (Institut für Serumforschung und Serumprüfung)located in Steglitz in the suburbs of Berlin.29 The main function of the insti-tute was the testing of sera, but it also enabled Ehrlich to focus on laboratoryresearch into diphtheria.Ehrlich was now able to work on his own method and theory of serumstandardization and develop the set of practices that constituted the originalversion of Wertbestimmung.After only a year, Ehrlich presented his ground-breaking achievements in a now classic study, The Assay of the Activity Cay-Rüdiger Prüll 17of Diphtheria-curing Serum and Its Theoretical Basis.30 The starting pointfor his research was the practical problem that the dose of diphtheriaserum administered to patients was often far too weak, so that repeateddoses had to be given to the same patient.This widespread problem was amystery since the phials of serum only left the manufacturers after havingsuccessfully passed a test of their efficacy.Ehrlich also experienced thisapparent loss of strength with his own test serum, which served as the basisfor checking the samples from the various companies.Normally, a specificamount of diphtheria toxin could be neutralized by 0.23 cubic centimetresof this test serum, but Ehrlich noticed that the potency of both toxin andserum decreased over time.The determination of the neutralization pointstarted to lose its former meaning, presenting the challenge of developingnew standards to evaluate the efficacy of diphtheria antitoxin samples.31From the beginning, this challenge was twofold.First, using mathematics,Ehrlich had to find a practical way of correlating the amounts of antitoxinsand toxins that could neutralize one another.He also wanted to determinewhy the serum samples lost their potency, which would require rethinkinghis theory of immunization.Ehrlich started with the pragmatic side of the research, checking andimproving all the measures aimed at conserving the samples.To avoid thedeleterious influences of water, oxygen, light and heat, Ehrlich adoptedBehring s method of storing the serum as a dry powder and inserting thepowder into vacuum tubes.32 The second step was to standardize the serum,and for this Ehrlich turned once again to goats for the antitoxin, withimmunization experiments conducted on guinea pigs.The method used atthe time was to introduce a specific amount of toxin into a guinea pig andthen inject a sufficient amount of test serum to neutralize the toxin so thatthe animal would survive at least four days.This method proved unsatisfac-tory as it depended too much on the researcher s subjective evaluation ofthe animal s condition.In his search for a more reliable method, Ehrlichfocused on the death of an experimental animal as the most objectivecriterion on which to base the evaluation of the efficacy of diphtheria sera.Reviewing his old experiments, he decided that the single lethal dose oftoxin would form a reliable starting point for his evaluations.33 He definedthis lethal dose as the amount of toxin that killed a 250 gram guinea pigwithin four days, and developed an elaborate method for precisely deter-mining this quantity.He selected a batch of diphtheria serum capable ofneutralizing one hundred lethal doses of toxin, and tested 11 samples ofdiphtheria toxin (each from a different origin) against the standardizedserum, using guinea pigs.Then, he successively added poison from thesample under test until he arrived at the one hundred and first dose, which,based on his theory (assuming a model of serum-toxin neutralization), wasthe amount needed to kill the guinea pig within four days.This enabledhim to find two threshold concentrations for each analyzed sample of 18 Paul Ehrlich s Standardization of Serumdiphtheria toxin [ Pobierz caÅ‚ość w formacie PDF ]
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.Furthermore, the appropriate dose for treating the children effec-tively could only be estimated for the serum produced at Koch s Institute,and these doses could not be applied either to sera coming from elsewherein the German Reich or from outside Germany.25The problems were now clearly posed, and Ehrlich aimed to solve themusing immunological theory based on chemical laws applied to medicineand supported by mathematics.Ehrlich received backing for his serologicalwork from the Prussian Ministry of Science and Education (Ministerialrat impreußischen Kultusministerium), thanks to the support of the prominent andpowerful Councillor, Friedrich Althoff (1839 1908).26 Previously, Ehrlichhad never received any official post in Koch s Institute, presumably becauseof his being Jewish,27 and when the control station for therapeutic sera(Controlstation für Heilsera) opened in the Institute in 1895, it was entrustedto Koch s assistants August Wassermann and Hermann Kossel and not toEhrlich, who was appointed deputy head of the department.28 But in 1896,at Althoff s instigation, Ehrlich became head of the new Institute for SerumResearch and Serum Testing (Institut für Serumforschung und Serumprüfung)located in Steglitz in the suburbs of Berlin.29 The main function of the insti-tute was the testing of sera, but it also enabled Ehrlich to focus on laboratoryresearch into diphtheria.Ehrlich was now able to work on his own method and theory of serumstandardization and develop the set of practices that constituted the originalversion of Wertbestimmung.After only a year, Ehrlich presented his ground-breaking achievements in a now classic study, The Assay of the Activity Cay-Rüdiger Prüll 17of Diphtheria-curing Serum and Its Theoretical Basis.30 The starting pointfor his research was the practical problem that the dose of diphtheriaserum administered to patients was often far too weak, so that repeateddoses had to be given to the same patient.This widespread problem was amystery since the phials of serum only left the manufacturers after havingsuccessfully passed a test of their efficacy.Ehrlich also experienced thisapparent loss of strength with his own test serum, which served as the basisfor checking the samples from the various companies.Normally, a specificamount of diphtheria toxin could be neutralized by 0.23 cubic centimetresof this test serum, but Ehrlich noticed that the potency of both toxin andserum decreased over time.The determination of the neutralization pointstarted to lose its former meaning, presenting the challenge of developingnew standards to evaluate the efficacy of diphtheria antitoxin samples.31From the beginning, this challenge was twofold.First, using mathematics,Ehrlich had to find a practical way of correlating the amounts of antitoxinsand toxins that could neutralize one another.He also wanted to determinewhy the serum samples lost their potency, which would require rethinkinghis theory of immunization.Ehrlich started with the pragmatic side of the research, checking andimproving all the measures aimed at conserving the samples.To avoid thedeleterious influences of water, oxygen, light and heat, Ehrlich adoptedBehring s method of storing the serum as a dry powder and inserting thepowder into vacuum tubes.32 The second step was to standardize the serum,and for this Ehrlich turned once again to goats for the antitoxin, withimmunization experiments conducted on guinea pigs.The method used atthe time was to introduce a specific amount of toxin into a guinea pig andthen inject a sufficient amount of test serum to neutralize the toxin so thatthe animal would survive at least four days.This method proved unsatisfac-tory as it depended too much on the researcher s subjective evaluation ofthe animal s condition.In his search for a more reliable method, Ehrlichfocused on the death of an experimental animal as the most objectivecriterion on which to base the evaluation of the efficacy of diphtheria sera.Reviewing his old experiments, he decided that the single lethal dose oftoxin would form a reliable starting point for his evaluations.33 He definedthis lethal dose as the amount of toxin that killed a 250 gram guinea pigwithin four days, and developed an elaborate method for precisely deter-mining this quantity.He selected a batch of diphtheria serum capable ofneutralizing one hundred lethal doses of toxin, and tested 11 samples ofdiphtheria toxin (each from a different origin) against the standardizedserum, using guinea pigs.Then, he successively added poison from thesample under test until he arrived at the one hundred and first dose, which,based on his theory (assuming a model of serum-toxin neutralization), wasthe amount needed to kill the guinea pig within four days.This enabledhim to find two threshold concentrations for each analyzed sample of 18 Paul Ehrlich s Standardization of Serumdiphtheria toxin [ Pobierz caÅ‚ość w formacie PDF ]