This study is conducted with the purpose to explore a certain aspects of the metabolism of bacteria by cell-free extracts. First of all a series of experiments have been carried out in order to obtain cell-free extracts of B. typhosa, S(57)S, that have respiratory activity; and the following results have been obtained. 1. Cell-free extracts prepared by ultrasonic and freezing-thawing method have been found to possess low respiratory activity on one or two substrates. 2, No set rules of destruction can be derived from the study of electron-micrographs of B. typhosa, S(57)S, destroyed by ultrasonic radiation and freezing-thawing processes. 3. Cell free extract of B. typhosa prepared by grinding with emery powder has been found to possess strong respiratory activity on lactate, succinate and fumarate.