Parte do artigo: Upon arriving at the Oswaldo Cruz Institute, I joined the team of Evandro Chagas, who was engaged in studies on kala azar (visceral leishmaniasis), recently verified in the country, which became the main subject of my first publications at the Institute. In the following year I was assigned to lecture Pathology in a course on malaria. I became so interested in the subject that I started investigating the so called “exoerythrocytic cycle” of Plasmodium, and published several articles, among which one that revealed the initial stages of the parasite before entering the red cells, recognized as a pioneer work by the eminent protozoologist CM Wenyon. Afterwards I returned to the studies on Leishmania, investigating the dissemination mechanism of the newly discovered L. enriettii into the organism of the natural host, the guinea pig. ....