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.
Scarlet fever is caused by an infection with group A streptococcus bacteria (usually strep throat). The bacteria make a toxin (poison) that can cause the scarlet-colored rash that gives this illness its name. Not all streptococci bacteria make this toxin and not all kids are sensitive to it.