Gradually pick away the shell at the large end. Note that there are two membranes and an air cell. Strip off the membranes. When sufficient shell and membranes have been removed from the large end, invert the open end of the egg in the salt solution and allow the contents to flow out. Care must be taken not to break the yolk. The embryo, or blastoderm, lies upon the surface of the yolk, which is usually turned with this body uppermost. Separate the blastoderm by cutting around the outside of the area vasculosa. In doing this a small pair of slightly curved scissors is needed. After the embryo, or blastoderm, has been separated, gently float it into a watch crystal with the flat bottom submerged in the salt solution. The watch crystal with its contents may now be gently lifted out. Next remove the vitelline membrane. The vitelline membrane is the delicate transparent membrane covering the blastoderm, The embryo is now ready for study. THE PREPARATION FOR STUDY OF ENTIRE EMBRYOS AND SECTIONS The following processes may be used in killing embryos up to four days, or ninety-six hours, of age. After removing the embryo as described above, spread the blastoderm out in the watch crystal and pipette off the salt solution. Allow it to stand till the edge of the tissue begin slightly to adhere. Then slowly add the killing fluid by aid of a pipette, dropping it on the center of the embryo. The pipette must be held low or the mechanical interference will dislocate the parts. Older embryos are submerged with their membranes intact into the killing fluid. The quantity of fluid should be several times the bulk of the specimen. Kleinenberg’s picrosulphuric acid may be used as a killing fluid. This fluid is a saturated solution of picric acid plus 2 per cent. sulphuric acid, to which is added twice its volume of water. Chick embryos from one to two days old should be left in this fluid from one and one-half to six hours. Embryos from two to four days old two and one-half to six hours. Remove the specimen from the killing fluid, and place it in 70 per cent. alcohol. Change the alcohol every twenty-four hours until the color ceases to come out of the embryo. Preserve in 80 per cent. alcohol. If the specimen is to be mounted whole, transfer it from 80 per cent., then to 50 per cent., then to 35 per cent., and, finally to water. Small embryos should remain in each fluid thirty minutes and large ones sixty minutes.