J.B.andS.M.McKinleyreachedasimilarconclusionina
studyofthedeclineoftenmajorinfectiousdiseasesin the
United
States.Theyshowedthatineverycaseexceptpoliomyelitis
the deathrate had already fallen dramatically (presumably
becauseofimprovedsanitationanddiet)beforeanynewform
ofmedicaltreatmentwasintroduced.Concentratingonthe 40
percentfallincrudemortalityintheUnitedStatesbetween
1910 and 1984, they estimated “conservatively” that
perhaps3.5percentofthefallintheoveralldeathratecanbe
explained through medical interventions for the major
infectiousdiseases.Indeed,giventhatitispreciselyforthese
diseases that medicine claims most success in lowering
mortality,3.5percentprobablyrepresentsareasonableupper-
limitestimateofthetotalcontributionofmedicalmeasuresto
the decline in infectious disease mortality in the United
States.^135
Rememberthat this 3.5percent isa figure forall medical
intervention. The contribution of animal experimentation
itselfcanbe,atmost,onlyafractionofthistinycontribution
to the decline in mortality.
Nodoubttherearesomefieldsofscientificresearchthatwill
behamperedbyanygenuineconsiderationoftheinterestsof
animalsusedinexperimentation.Nodoubt therehavebeen
some advances in knowledgewhich would not have been
attained as easily without using animals. Examples of
important discoveries often mentioned by those defending
animalexperimentationgobackasfarasHarvey’sworkon
the circulation of blood. They include Banting and Best’s
discoveryofinsulinanditsroleindiabetes;therecognitionof