An improved embedding method for electron microscopy of lepromata.

Spurr's resin mixture has been found to be the embedding material most suitable for electron microscopic studies of lepromata at present. Like methacrylate, it can penetrate well into foamy structures and the leprosy bacilli within foamy structures. On the other hand, like Epon 812, it is stable against the electron beam and can preserve ultrafine structures. Additionally, we have found that the use of dimethylformamide or dimethylsulfoxide instead of propylene oxide as substituter improves the preservation of the ultrafine structures of leprosy bacilli.