investigated the action of the venom of this snake on fibrinolysis and blood coagulation. Among his many other contributions to biomedical sciences are the development of a rapid staining for blood smears combining May–Grunwald and Giemsa techniques in 1947 (Rosenfeld staining), the introduction a new treatment for chronic leukemia using personal control of maintenance dosis (1955) and described hementerin, an anticoagulant isolated of a Brazilian species of leech (Haementeria depressa) jointly with Eva Maria Antonia Kelen in 1975. Bradykinin discovery In 1948, as part of a research team at the Instituto Biológico, Dr. Rosenfeld co-discovered, with two other Brazilian physiologists and pharmacologists, Drs. Maurício Rocha e Silva and Wilson Teixeira Beraldo, a new endogenous peptide capable of causing a powerful fall of blood pressure on animal preparations, which they called bradykinin. The substance, a short kinin with nine amino acids only, was detected in the blood plasma of dogs after the addition of venom extracted from the Bothrops jararaca snake, brought by Rosenfeld from the Butantan Institute. The discovery was part of a continuing study on circulatory shock and proteolytic enzymes related to the toxicology of snake bites, started by Rocha e Silva as early as 1939. Bradykinin was to prove a new autopharmacological principle, i.e., a substance that is released in the body by a metabolic modification from precursors, which are pharmacologically active. The discovery of bradykinin led to a new understanding of many physiological and pathological phenomena including circulatory shock induced by venoms and toxins. Ultimately, the extensive study of the origins of its formation in the body, by Sérgio Henrique Ferreira, a noted Brazilian pharmacologist, and others, led to the development of new anti-hypertensive agents in humans, such as captopril, developed by Squibb under the name of Capoten, and still widely used. However, the team of Brazilian scientists, including Rocha e Silva, Beraldo, Rosenfeld and Ferreira never came to enjoy the royalties of such discovery, since they always published in the public domain of pure scientific knowledge. Other activities Dr. Rosenfeld was also an important scientific leader, having been involved in the foundation of the Brazilian Society for the Advancement of Science, in 1949. In addition, he was an accomplished amateur photographer. A part of his photographic collection between 1962 and 1976 has been preserved at the Instituto Moreira Salles. References Kelen EM, & Gastão Rosenfeld (26/07/1912-15/07/1990). Ciência e Cultura 42(12)December 1990 Fan Hui Wen; Aline Solosando;