Abstract
Exposure of Dugesia tigrina to 5 X 10-5 M hexanolactone (HL) for 12-20 hrs. produced specific patterns of tissue lesion. Addn. of cysteine or glutathione to the medium antagonized the HL effect as judged by area of lesion, extent ? of repair and survival. Colorimetric and spectrophotometric studies showed the antagonism to be a direct and reversible reaction between R-SH and HL.