A process and apparatus for rapid, continuous flow histological processing of tissues is disclosed. The steps of fixation, dehydration, clearing and impregnation are performed in less than one hour; this allows a pathologist to evaluate samples shortly after receipt, perhaps while the patient is still in the operating room. Rapid and continuous processing is accomplished by decreasing the thickness of tissue sections, use of nonaqueous solutions composed of admixtures of solutions, solution exchange at elevated temperature and with agitation, and impregnation under vacuum pressure. The patient in surgery is thus provided with point-of-care surgical pathology.