Which preposition to use with koch

on Occurrences 2%

By J.C. PETERS, M.D. Dr. Koch on the Cholera. Malaria.

in Occurrences 1%

Such a case was a Frenchman named Canarie (and the colour of his face, upon admission, did not belie his name), who had been treated for blackwater fever by the great Koch in Uganda many years before, and had been warned by him against big doses of quinine.

Which preposition to use with  koch