This depends on the condition of the bill. In normal used condition, they are worth exactly $2. $2 bills dated 1976 and newer are the ones worth face value only. The $3/$4 figure is reasonable for bills dating back to the 1950s.
Klein thought he had, discovered the poison to be due to a disease of the cow. An epidemic of scarlet fever broke out in London in December, 1885, and the outbreak could be traced to the milk supplied by a herd in Hendon.
History of syphilis - History of diagnosis. 1  In 1905, Schaudinn and Hoffmann discovered Treponema pallidum in tissue of patients with syphilis. One year later, the first effective test for syphilis, the Wassermann test, was developed. Although it had some false positive results, it was a major advance in the detection and prevention of syphilis.