After the experimental removal of the most part of caecum of rabbit, when it is bred over 100 days, the remained portion of the caecum is enlarged distinctly and not only the spiral plicae increases its number but it is partly formed a peculiar caecal-dilatation, projecting against the colon-side. The muscular layer of caecum-wall is generally thickened, especially the epithelium is markedly proliferated. This is a regenerative phenomenon on the caecum of which damaged portion is to be filled and partly regains the characteristic shape of caecum and at the same time shows the systematical changes on the whole caecum-tissue. Consequently it may be admitted that these changes are not merely the regeneration of tissue of caecum but it is a regenerative process as an organ. However, literature on this subject hold the same view that each tissue of intestinal canals of mammalia is independently regenerated but the regeneration of an organ is not acknowledged. Korschelt states in his book that " Die ausgebildeten Wirbeltiere zeigen keine eigentliche Regeneration der einzelnen Abschnitte des Darmkanals. Wenn von einer solchen die Rede ist, handelt es sich nur um den Ersatz von Teilen der Schleimhaut, die sowohl im Magen, wie in den darauffolgenden Darmpartien stattfindet . . . ". On the other hand, the fact shown by my experimental results on mammalia such as rabbit, proved the regenerative process of intestinal canals, and I believe that it is a new information which overthrows the old established view. On the subject of caecumregeneration, Schmalhausen and others have alreacly pointed out that the morphotgenesis of the regenerated organ or tissue is closely connected with the function or its mechanical element, and in case of the regenerative process of rabbit-caecum, its functional relation is undoubtedly the important factor. There are many theories on the caecum-function and caecum of herbivorous animal such as rabbit plays an important role on the digestion and resorption of cellulose as it has been hitherto marked by Tullberg Ustjnzezw Elllenberger and others. Any herbivorcus animal which takes food which is rich with cellulose, posseses the large caecum, and it is a well known fact that Such food taken is stored in the caecum for a long while and sufficient liquid and putrefactive action decompose the cellulose and completely digests. The remained portion of the excised caecum of rabbit partly regains its peculiar cul-de-sac which is physiologically formed as above described, and at least it may be said that the anatomical structure of caecum in which the intestinal contents isolated from the main intestinal canals is stored for a long while which signifies an importance of its function and again a part of the morphological changes in caecum-regeneration is probably a functional adaptation concerning the digestion and resorption of cellulose. Among the intestinal-tissues, the mucous membrane manifests most distinctly its regenerative activity and also the epithelium of mucous membrane on the originally remained portion of caecum is remarkably proliferated. Thus the defect of the caecum-tisseue is compensated by the hypertrophy. Such proliferation is not observed in all the intestinal canals except the caecum alone. Therefore, the epithelium of the caecum appears to monopolize this special function which the small intestines and colon are unable to compensate. </p
