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.
The incubation period for scarlet fever is about 12 hours to seven days. Risk factors for scarlet fever include overcrowding, especially with children age 5 to 15 years old and the communal use of utensils, towels, or other substances.