He was arrested twice for his political activities , in 1877 and again in 1878 , but released both times after only a short time in jail .
Thereafter , Plekhanov was forced by the fear of retribution to lead an underground life .
Plekhanov was arrested twice for Plekhanov 's political activities , in 1877 and again in 1878 , but released both times after only a short time in jail .
Thereafter , Plekhanov was forced by the fear of retribution to lead an underground life .