Borneo, the geographical center of the Indonesian world, appears also to be the district in which these instruments are most popular. The _ampallang, palang, kambion_, or _sprit-sail yard_, as it is variously termed, is a little rod of bone or metal nearly two inches in length, rounded at the ends, and used by the Kyans and Dyaks of Borneo. Before coitus it is inserted into a transverse orifice in the penis, made by a painful and somewhat dangerous operation and kept open by a quill. Two or more of these instruments are occasionally worn. Sometimes little brushes are attached to each end of the instrument. Another instrument, used by the Dyaks, but said to have been borrowed from the Malays, is the _palang anus_, which is a ring or collar of plaited palm-fiber, furnished with a pair of stiffish horns of the same wiry material; it is worn on the neck of the glans and fits tight to the skin so as not to slip off. (Brooke Low, "The Natives of Borneo," _Journal of the Anthropological Institute_, August and November, 1892, p. 45; the _ampallang_ and similar instruments are described by Ploss and Bartels, _Das Weib_, Bd. i, chapter xvii; also in _Untrodden Fields of Anthropology_, by a French army surgeon, 1898, vol. ii, pp. 135-141; also Mantegazza, _Gli Amori degli Uomini_, French translation, p. 83 et seq.) Riedel informed Miklucho-Macleay that in the Celebes the Alfurus fasten the eyelids of goats with the eyelashes round the corona of the glans penis, and in Java a piece of goatskin is used in a similar way, so as to form a hairy sheath (_Zeitschrift für Ethnologie_, 1876, pp. 22-25), while among the Batta, of Sumatra, Hagen found that small stones are inserted by an incision under the skin of the penis (_Zeitschrift für Ethnologie_, 1891, ht. 3, p. 351). In the Malay peninsula Stevens found instruments somewhat similar to the _ampallang_ still in use among some tribes, and among others formerly in use. He thinks they were brought from Borneo. (H.V. Stevens, _Zeitschrift für Ethnologie_, 1896, ht. 4, p. 181.) Bloch, who brings forward other examples of similar devices (_Beiträge zur Ætiologie der Psychopathia Sexualis_, pp. 56-58), considers that the Australian mica operation may thus in part be explained.