Hypodermic syringes, for injecting medicines into muscles or veins, were invented in 1848 and, until after World War I, were handmade of glass and metal by skilled craftsmen. They were expensive, delicate, and meant to be reused like any other precision medical instrument. During the 1920s their manufacture became mechanized, to the point where 2 million syringes were produced globally in 1930, making them more available but not more expendable. To the medical officers working in Central Africa at that time, they seemed invaluable but were in short supply.
