We developed a technique that permits the use ofserial 5cctiwis (7-20 .tm) from a single fixed piece of bone tissue for immunofluorescence, measurement of fluorescent bone labels, enzyme histochemistry, and general staining. This technique combines modifications ofpreviously established methods with perfusion ofthe polymer polyvinylpyrrollidone (PVP) to improve sectioning, and produces reliable sections with good preservation of both hard and soft tissues. The combination of techniques from several workers, the use of perfusion with a polymer to inaease the sectionability of the bone, and the addition of a gelatin adhesive on top of pressure-sensitive adhesives represent a significant improvement over previously described methods. The sections obtamed are usable for immunocytochemistry, general staini Supported in part by grants from 3M Company and The University of Minnesota Graduate School.