The Author has studied the intradermal reaction on 20 cases of leprosy (13 L and 7 N) by antigens from cultures of acid-fast bacilli, obtained by SOUZA-ARAUJO in the Instituto Oswaldo Cruz ("SOUZA-ARAUJO's leprolins 1, 1a, 3, 5, 5a") and by the lepromin. The experiments were carried out in the "Hospital Colonial São Roque", at the State of Paraná, Brazil. He has observed: 1. That lepromin has produced the same classical results: positive in the nervous cases and negative in lepromatous ones. 2. That SOUZA-ARAUJO's leprolins" and lepromin, were done at th same time, without great malaise to the patients. In two lepers have developped the lepra reaction during the experiments; oe, a little fever, another with fusion of the lepromatous lesions in his skin.