This competitive renewal application seeks continued support for the operation of a Morphology Core within the Washington University Diabetes Research and Training Center. The Core's long term goal is to support diabetes research by providing light microscopy services to DRTC investigators. This Core has undergone extensive reorganization and reduction in size with the elimination of the electron microscopy services formerly provided by the Core. Three types of services are provided: (1) processing of unstained samples, (2) hematoxylin-losin stains and (3) special stains that include aldehyde fuchsin, giemsa, mason trichrome, oil red O, bielschowsky, reticulum, phosphotungstic acid and PAS.