Since the discovery of the teratogenicity of trypan blue by Gillman, Gilbert, Gilhnan and Spence (1948) the dye has offered a very concise and convenient method for studying teratogenesis in mammals. Dijkstra & Gillman (1960) fractionated the dye and found that the purple component stimulated the endothelial system in rats, thereby raising the speculation that the varied effects of the dye were caused by contamination. According to our previous experiments (1957, 1963) and those of Wilson, Beaudoin & Free (1959) one aspect of the problem has remained fairly constant, namely, the narrow time limit of the maximal effect of the dye and the stability of the pattern of malformations. Wilson and his associates suggest that the teratogenic effect is due to direct access of the dye to the embryo before the visceral yolk-sac is completely formed.

This content is only available via PDF.