1. The outer surface of eggs should be sterilized with alcohol and 1 mL of albumen removed via the blunt end of the egg using a syringe and 21-gage needle.
2. Eggs can then be windowed by cutting a hole in the top using a scalpel or curved scissors (see Chapters 14 and 16). Avoid pointing the blades of the scissors down into the egg, since this may damage the embryo.
3. Embryos can then be visualized by subblastodermal injection of ink (about 100 pL) using a 25-gage needle. Inject the ink outside the area opaca at a shallow angle, and minimize the size of the hole.
4. Eggs can be resealed with pieces of Sellotape and left at room temperature (or in the incubator) until they are to be used (see Note 1).
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