Progress was not at a standstill during this time, however, but, on the contrary, chemical precipitation of sewage and purification by the application to land were striving with each other for supremacy. Up to that time, the important part that bacteria play in the reduction of organic matter was not understood, and instead of affording every advantage for the decomposition and fermentation of organic matter under the least objectionable conditions, the principal efforts of those interested in the problem were to prevent or put off as long as possible the septic action of sewage. It was not until so late as the year 1880 that attention was turned toward the possibility of the micro-organisms in sewage. In that year Dr. Mueller took out a patent endeavoring to utilize the micro-organism in sewage for the purpose of purification. According to Dr. Mueller's views, "The contents of sewage are chiefly of organic origin, and in consequence of this an active process of decomposition takes place in sewage through which the organic matters are dissolved into mineral matters, or, in short, are mineralized, and thus become fit to serve as food for plants. To the superficial observer, however, it is chiefly a process of digestion, in which the various, mostly microscopically small, animal and vegetable organisms utilize the organically fixed power for their life purpose. "The decomposition of sewage in its various stages is characterized by the appearance of enormous numbers of spirilla, then of vibrios (swarming spores) and, finally, of moulds. At this stage commences the reformation of organic substance with the appearance of chlorophyl-holding protococcus." About the same time, December, 1881, the account of Mouras's automatic scavenger was published in France. Mouras had been working and experimenting along the same lines as Dr. Mueller, and the result was an apparatus consisting of a closed vessel or vault, with a water seal which rapidly changed excrementatious matter into a homogeneous fluid, only slightly turbid, and holding the solid matters in suspension in the form of scarcely visible filaments. The principle claimed for his automatic scavenger by Mouras was that animal dejecta within themselves contained all the principles of fermentation necessary to liquefy them.