Hertwig Oscar, born the April 21st 1849 with Friedberg and dead the October 25th 1922 with Berlin, is a German Embryologiste .

He studied the Médecine with Ernst Haeckel and Karl Gegenbaur. In 1875, it establishes that the Fertilization is the union of the Noyau of a Gamète Mâle with a gamète Femelle. He also worked on malformations of the Embryon S of Vertébré S.