A novel sectioning technique for use in descriptive embryology: Bridging the gap between paraffin and plastic serial sections

A novel sectioning technique for making serial sections for use in descriptive embryology is presented. This technique allows one to obtain good‐quality sections (5‐ to 10‐μm thick) of embryos embedded in plastic, several times faster than with conventional plastic sectioning techniques. Furthermore, this technique can be used to serially section embryos until desired levels are reached. One‐micrometer or thin (50–100 nm) sections can then be cut for study, respectively, by light and transmission electron microscopy. The resolution of cellular morphology in 5‐ to 10‐μm sections is intermediate to that of paraffin and 1‐μm plastic sections, and gross tissue distortions typically present in paraffin sections are absent in plastic sections. Thus, in terms of convenience and section quality, this technique bridges the gap between those routine techniques used for preparation of conventional paraffin and plastic serial sections.