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		Materials and Methods: We will use 36 2-day old chicken embryos at H&H stage 12 for this experiment. We will place twelve eggs into three groups: control, 12.5ug and 25ug of lead acetate. The control group will receive distilled water rather than lead acetate. We will inject 0.1ml of the different concentrations of lead acetate or distilled water into the yolk sac of the 2-day old embryos with a needle and seal the hole with scotch tape. We will incubate the embryos in 37C for two days. After incubation, the chick embryos will be four days old and should be H&H 24. We will remove all 12 embryos from each group (control, 12.5ug, and 25ug) from the shell and yolk sac and observe the development under a dissecting microscope. We will stage the embryos and observe any morphologic malformations of the neural components of the chick embryos, such as the fore-, mid-, and hind-brain.