Family tree and relation to biographer Edgar Bonjour According to this the historian Edgar Bonjour was the son in law of Kocher A monograph on Kocher s life was written by the well known Swiss historian and son in law Edgar Bonjour 1 While Bonjour 1898 1991 married Dora Kocher 1914 2004 see also Kocher did not have any daughters and the birth date of 1914 makes it more likely that Dora was a grandchild of Theodor Kocher From this document Kocher Dora und Gertrud an ihre Mutter Kocher Berta 1880 1929 it seems that Doras mother was Berta According to the most likely family constelation was Theodor Kocher 1841 1917 Maria Witschi 1841 1921 Arthur Otto 1876 19 salesman prob died between 1925 and 1930 Johann Albert Kocher 1872 1941 doctor and lecturer at the university Albert Theodor Kocher 1870 1950 doctor Berta Lauterburg 1880 1929 Gertrud Kocher 1909 Kocher Gertrud Agnes Friederike 1909 195 Dora Kocher 1914 2004 Edgar Bonjour 1898 1991 while the Nobel biography describes Johann Albert 1872 1941 as oldest son who became his fathers assistant he is also the one that is listed as lecturer at the university and thus it is likely that he was the one helping his father but was not the oldest son