There are many problems affecting microscopy in Xenopus. Xenopus oocytes and embryos are fragile and lack connective tissue. They are also full of yolk platelets, which prevents frozen sectioning because the yolk crystallizes and tears the sections. In addition, the yolk autofluoresces, making whole-mount immunocytochemistry possible, but difficult due to background from out-of-focus fluoresecence. All of these problems can be solved through confocal microscopy. Optical sectioning eliminates the need for manual sectioning and makes background fluorescence and autofluorescence negligible. It is still difficult to image the deep structures within the embryo, but thick wax sections can be cut and confocal microscopy again applied.