Oscar Hertwig

Oscar Hertwig was a German zoologist and professor who also wrote about the theory of evolution in c. 1916, over 55 years after Charles Darwin's book The Origin of Species. He was the elder brother of zoologist-professor Richard Hertwig (1850–1937).The Hertwig brothers were the most eminent scholars of Ernst Haeckel from the University of Jena. They were independent of Haeckel's philosophical speculations but took his ideas in a positive way to widen their concepts in zoology. Initially, between 1879–1883, they performed embryological studies, especially on the theory of the coelom (1881), the fluid-filled body cavity. These problems were based on the phylogenetic theorems of Haeckel, i.e. the biogenic theory, and the "gastraea theory".