ABSTRACT
The evolution of knowledge of medical protozoology and the history of the basic discoveries in free-living and parasitic amebas can be divided into specific periods of time, giving the reader an overall historical perspective of the events leading to our present state of knowledge. The evolution of this knowledge is patched with provocative ideas, exciting theories, innovative hypotheses, and startling discoveries which are significant examples of human curiosity. These advances in knowledge, positive accomplishments, and achievements stimulated studies and new discoveries, leading to the clarification of the role played by free-living or amphizoic amebas in human and animal infections. A fortuitous animal inoculation test which, for the first time, revealed the pathogenicity of a Limax ameba and the production of meningoencephalitis in the laboratory animals. Fatal human cases discovered with histopathological features similar to those produced by Limax ameba in the laboratory animals. Isolation of amebas from the fatal human cases.
