Ivan Romanovich Tarkhanov (Russian: ???? ????????? ????????) or Ivane Tarkhnishvili (Georgian: ????? ???????–?? ???????????, ??????-???????; June 1846 – September 1908) was a Georgian physiologist and science populariser from the Tarkhan-Mouravi noble family.
He led the Department of Physiology at the Academy of Military Medicine from 1877 to 1895 and authored a slew of articles on physiology for the Brockhaus and Efron Encyclopedic Dictionary.
Among his numerous contributions was the discovery of the skin galvanic reflex (1889).
However, Tarkhnishvili's most significant contribution was the discovery of the influence of X-rays on the central nervous system, animal behavior, the heart and circulation, and embryonic development (1896-1903).
Indeed, these works have given rise to a new field in science as Radiobiology.