抄録
The mamillary body of the mammals always consists of two nuclei, the medial and lateral. The medial nucleus consists of small nerve cells and the lateral nucleus the large nerve cells. In the pigs and dogs, the cell group extends in a belt-like fashion towards the ventral side of the medial nucleus and reaches the lateral nucleus of the mamillary body forming an arch-like structure along the ventral side of the medial nucleus. This cell group is called nucleus inframammillaris. In the silver-impregnated specimen, the size and morphology of the nerve cells are quite similar between the lateral and the inframammillar nucleus, so that the nucleus inframammillaris should be considered to be a part of the lateral nucleus. Inside of the mamillary body, the nerve endings surround the nerve cell in the form of a terminal button. This would definitely indicate that the mammillary body is an interposed gray matter. The medial nucleus of the mamillary body of the Japanese monkey is further divided into the dense dorsal portion and the coarse ventral portion. In the dense portion, the arrangement of the cells is dense and the arrangement of the nerve fibers is complex. Fuse1) found the formation of the cell folds in the medial nucleus of the mamillary body in 5 kinds of monkeys, suggesting an intimate relationship between the nerve fibers entering into and emitting from the mamillary body and the cellular elements in the mamillary body. The observations in the Japanese monkeys tend to support Fuse's concept.
