Abstract: A novel method for determining the teratogenic potential of an agent of unknown teratogenic effect is described. This novel method comprises the steps of providing a plurality of artificial embryos, chronically exposing the embryos to varying concentrations of test agents, observing the exposed embryos over time to estimate a minimum teratogenic concentration of the test agent required to interfere with the development of the embryo, and comparing the minimum teratogenic concentration to a minimum adult reference concentration of the test agent which is toxic to normal adults. In this manner, the teratogenic potential of the test compound is indicated by the degree of difference between the teratogenic and adult reference concentrations.

Abstract: A system and apparatus for the growth of hydrozoa, e.g. hydra is disclosed which comprises a tank having a fluid medium therein for the growth of the hydra and pump means for recycling and filtering the medium. Temperature control and oxygenation apparatus may also be provided. In a preferred embodiment, the tank has a roughened surface for the attachment of hydra thereto so as to form a stable resident population of hydra. When it is desired to remove a quantity of hydra for an experiment, they can be dislodged from the surface by means of, e.g., a razor blade and collected, by means of the recycle current, on a net disposed in the current path.