In 1905, a Colombian naturalist, Dr. RAFAEL ZERDA BAYON, returning from a scientific mission of exploration through the poorly known territories of the Colombian Caquetà and Putumayo, reported, with a rich harvest of documents and raw materials of plant origin, a liana, haloed with a strange and wonderful legend: the yagê. He isolated from it, by very simple means, a raw alkaloide, to which, for reasons that will be seen later, he gave the unexpected name of telepathin. The interest of this "plant to the prophets" prompted other Colombian researchers to take over from it. G. CARDENAS, in 1923, made it the subject of a short medicine thesis. Ms. GEORGINA Muffoz v. DE SALINAS began a series of interesting psycho-physiological tests to be published soon. Recently Professor BARRIGA VILLALBA of the University of Bogota, with abundant materials, resumed and pushed further the chemical study of yage. He isolated in crystallized state, and first studied the alkaloid of ZERDA BAYON, whose name he changed to the most appropriate yagein. He also discovered a second one he called yagenin. This is the translation of his work published in the Boletin of the Sociedad Colomhiana de Ciencias Naturales de Bogota, March 1925, which we give below.