Effects of Colchicine on the Frog in Relation to Ovulation and Early Development

Abstract

Summary and Conclusions

Colchicine was used in concentrations ranging from 1:1000 to 1:1,000,000. It was found to act as a capillary poison, to prevent ovulation when injected into sexually-mature female frogs prior to anterior pituitary stimulation, to prevent cleavage of normal eggs exposed to spermatozoa previously treated with colchicine, to affect gastrulation to such an extent that exo-gastrulae were the rule, to inhibit the appearance of organ anlage when applied just before the normal appearance time, to retard general growth of the larvae to such an extent that cephalic structures were markedly stunted and hatching prevented. The cytological picture was one of many pycnotic nuclei, occasional multinucleated cells, few metaphase figures, and apparent resting stages of mitosis.