Effect of vinblastine sulfate on the growth and histologic development of reaggregated hydra

In the presence of vinblastine, the sorting of individual cells proceeded normally but mesogleal formation was delayed. The “embryo” became highly distended and failed to expel a central mass of unused or residual cells as occurs during regeneration of “embryos” that have not been treated with a test chemical. The epithelial cells became vacuolated and failed to maintain their sheetlike arrangement and attachments, although they did begin secretion of basement membrane. Interstitial cells failed to increase in number.