A first description of the etiology of trachoma was published in 1907. During expeditions to Java to study the transmission of syphilis, Halberstaedter and von Prowazek infected orangutans with conjunctival scrapings from trachoma patients and such agents in conjunctival smears. They called them "chlamydozoa". J. Ritter in 1879 published the first case description of psittacosis, describing a mini-epidemic in which three of seven patients died, and identified the source of infection, determined the incubation period and the nontransmissibility of the disease from human to human. In 1895 the term psittacosis was first applied. In 1893, Nocard isolated a Gram-negative bacterium from parrots dying of psittacosis (Bacillus psittacosis). This organism was subsequently found in human or avian subjects and was later diagnosed as Salmonella. The inconsistent bacteriological findings prompted a search for a filterable virus during the pandemic of 1929-1930. Almost simultaneously, Levinthal (1930), Coles (1930) and Lillie (1930) described small, filterable bodies in infectious material called "Levinthal-Coles-Lillie (L.C.L.) bodies". Bedson first suggested the biphasic development cycle in 1932 after having studied tissues from inoculated mice. In 1935, Burnet and Rountree propagated "the virus" on the chorioallantoic membrane of embryonated chicken.