Dora “Dorchen” Richter (1891 – presumed 1933) was the first known person to undergo complete male-to-female gender reassignment surgery. She was one of a number of transgender people in the care of sex-research pioneer Magnus Hirschfeld at Berlin’s Institute for Sexual

Zinc was identified to be essential in fungal growth of yeast as shown by Jules Raulin in 1869 yet no proof for the need of zinc in human cells was shown until the late 1930s where its presence was demonstrated in carbonic anhydrase and the 1960s where it was ident