american eugenics society capital budgeting distributed lag economics equation of exchange eugenics eugenics record office federal reserve bank of st louis fisher equation fisher hypothesis fisher separation theorem great depression herbert hoover inflation inflation rate interest rate investment jack hirshleifer james tobin john maynard keynes joseph schumpeter marginalism mathematical economics mathematics mcmaster university money illusion neoclassical economics nominal interest rate phillips curve price index quantity theory of money real interest rate relative price saugerties schools of economic thought tuberculosis unemployment united states vector space william graham sumner yale university