Occurrence of a gomoriphil tuberohypophyseal tract in the dog.

Following the reports of J. L. Pines (1925) and R. Grevi ng (1926) on tractus supraoptico-hypophyseus, a nerve tract running from nucleus supraopticus to the hypophysis, the existence of tractus supraopticohypophyseus and tractus paraventricularis cinereus (tractus paraventriculohypophyseus) communicating the large cellular nuclei of the hypothalamus (i. e, nucleus supraopticus, nucleus supraopticus accessorius, nucleus paraventricularis and nucleus mamilloinfundibularis) with the hypophysis has been demonstrated. The cells forming these nuclei are known to be neurosecretory cells possessing secretory activity and it has also been demonstrated that nerve tracts arising from these cells are gomoriphil neurosecretory pathways (W. B a rgm an n 1949, 1954, E. Scharrer & B. Scharrer 1954). Recent studies have aroused interest on the existence of a nerve tract other than these tracts which arise from the large cellular nuclei, a nerve tract supposed to regulate chiefly the sexual function (G. W. Harris, 1948, H. Spatz 1951). Though the site of the originating cells of the latter is believed to be found in tuber cinereum, no conclusive evidence has been given. Whether the nature of this nerve tract is centrifugal or centripetal, or in what part of the hypophysis this nerve tract terminates are problems still to be investigated. The findings given in this paper on dog have convinced me of the existence of a gomoriphil tract running from tuber cinereum to the hypophyseal area.