Tunisian and French healthcare officials, and organized the Institute such that other medical functions (such as caring for sick patients) would monetarily support the Institute's ongoing laboratory research. Doing so gave him autonomy to run the Institute without relying on public or governmental funds. As the Institute grew more financially stable, Nicolle tackled the diseases and public health concerns that were prevalent in the local region, shared research findings and resources with the Paris Institute, and expanded his scientific writings into a journal called the Archives de l’Institut de Tunis. He also became a key point of contact for the French government when new epidemics arose that required his intervention – such as in the malaria epidemic of 1906 and the cholera outbreak of 1907. During this time, Nicolle also undertook two major projects that would come to define his role in the scientific communitythe discovery of the mode of transmission of typhus (an infectious disease prevalent throughout North Africa and the Mediterranean Basin at that time) and the production of vaccines. Discovery of the vector transmitting typhus Nicolle's discovery came about first from his observation that, while epidemic typhus patients were able to infect other patients inside and outside the hospital, and their very clothes seemed to spread the disease, they were no longer infectious when they had had a hot bath and a change of clothes. Once he realized this, he reasoned that it was most likely that lice were the vector for epidemic typhus. Because studying the transmission of typhus required that the parasite be alive (needed a human host), scientists were only able to study it during epidemic times. However, Nicolle found that the chimpanzee served as a suitable alternate host for this study since it was genetically similar to humans, and in June 1909, Nicolle tested his theory by infecting a chimpanzee with typhus, retrieving the lice from it, and placing it on a healthy chimpanzee. Within 10 days, the second chimpanzee had typhus as well. After repeating his experiment, he was sure of it: lice were the carriers. As Nicolle continued his ongoing research on the disease, he later switched to using guinea pigs as his model organism instead of chimpanzees as they were just as susceptible to infection and were also smaller and cheaper. An important finding from further research showed that the major transmission method was not louse bites but excrement: lice