As everyone knows, the final goal of morphological and immunohistochemical studies in our biological or medical fields is that all findings examined in animal experiments should reflect the physiologically functional background. Therefore, the preservation of all original components in targeted cells and tissues of animals is necessary for describing the functional morphology of living animal organ s . It has been generally accepted that morphological findings of various animal organs were easily modified by stopping their blood supply, because of ischemia or anoxia . There had been a need to develop a new preparation technique for freezing the living animal organs in vivo and then obtaining their acceptable morphology and also immunolocalizations of original soluble component s in functioning cells and tissues. We have already developed the “in vivo cryotechnique ” (IVCT) not only for their morphology, but also for immunohistochemistry of many soluble components in various living animal organs [6–9]. All physiological processes of them were immediately immobilized in the vitreous ice by IVCT, and every component in the cells and tissues was maintained in situ at the time of freezing. Thus, the ischemic or anoxic artificial effects on them could be minimized by the newly developed IVCT. Our specially designed liquid cryogen system with or without a cryoknife has totally solved the morphological and immunohistochemical problems which are inevitable by the conventional preparation methods at a light or electron microscopic level [6, 8]. The IVCT has been found to be extremely useful to arrest transient physiological processes of cells and tissues and also to maintain their intra- and extracellular components in situ, such as rapidly changing signal molecules, membrane channels, and receptors, as described before [8, 9].