Inventions You Didn’t Know Were Made By Women Modern Syringe In 1899, Letitia Geer invented a one-hand-operated medical syringe. Although syringes existed before that, Letitia’s invention allowed doctors to use just one hand to operate syringes. Previous Next 1 2 3 4 5 6 7 8 9 10 11 12 13 14 2020-03-31 admin Share ! tweet