The lysosomal cycle has been studied in the primary cultures of corneal epithelium infected with type I herpes virus. Immediately after the infection, the lysosomal system develops. There is a great dispersion in the morphometric analysis of the lysosomal particles. They represent a heterogeneous population with regard to their size. The number of lysosomal particles increases very rapidly during the first hours after the herpetic infection. Finally many cells become round and die.