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.
Ever since HIV-1 was first discovered, the reasons for its sudden emergence, epidemic spread, and unique pathogenicity have been a subject of intense study. A first clue came in 1986 when a morphologically similar but antigenically distinct virus was found to cause AIDS in patients in western Africa (Clavel et al.cquired immunodeficiency syndrome (AIDS) of humans is caused by two lentiviruses, human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2). Here, we describe the origins and evolution of these viruses, and the circumstances that led to the AIDS pandemic.