The 24-hour rhythm of cellular division is preserved in symmetrical cornea by inflicting corneal burns in the morning. However, the average values of mitotic coefficients during the whole experiment appear to be lower than in the cornea of normal animals. The infliction of burn in the evening has no effect on the character of the 24 hour rhythm. However the general level of mitotic activity is much higher. A stable depression of the tempo of cellular division was noted in the injured cornea.