The 1840 census was the first that attempted to count Americans who were "insane" or "idiotic". Published results of the census indicated that alarming numbers of black persons living in non-slaveholding States were mentally ill, in striking contrast to the corresponding figures for slaveholding States. Pro-slavery advocates trumpeted the results as evidence of the beneficial effects of slavery, and the probable consequences of emancipation. Anti-slavery advocates contended, on the contrary, that the published returns were riddled with errors, as detailed in an 1844 report by
Edward Jarvis of Massachusetts in the
American Journal of the Medical Sciences, later published separately as a pamphlet, and in a memorial from the
American Statistical Association to Congress, praying that measures be taken to correct the errors. The memorial was submitted to the House of Representatives by
John Quincy Adams, who contended that it demonstrated "a multitude of gross and important errors" in the published returns. In response to the House's request for an inquiry, Secretary of State
John C. Calhoun reported that a careful examination of the statistics by the supervisor of the census had fully sustained their correctness. The returns were not revised. ==Census questions==