A study of the mechanism of action of colchicine on embryos ofMicrohyla ornata.

1. The effect of colchicine on developmental stages ofMicrohyla ornata has been studied. 2. Treatment with colchicine at early neurula stage (stage 14-15) has no effect on development. 3. Treatment with colchicine at early stages of development caused 1. Suppression of gastrulation, 2. Oedema, 3. Microcephaly, 4. Eye defects and 5. loss of pigmentation. 4. The effects of colchicine could be completely reversed by subsequent treatment with cysteine hydrochloride (2.5 μg/ml). 5. The possible modes of action of colchicine have been discussed.