APPENDIX. 307 



into evacuation pipes of the sewer by special syphons, and 

 help to flash them. This system has been applied to the 

 Hotel de Ville, to the new Guards' barracks, to a certain 

 number of primary schools, and to many private houses. 

 The municipal administration proposes to apply this 

 system to most of the schools, hospitals, and barracks, of 

 which the sanitary condition is at present far from satis- 

 factory. They hope eventually to extend the same system 

 to all private houses, so as to do away with the cesspools 

 a reform already effected in many foreign cities, and 

 notably in Germany. 



F. 



APPENDIX TO CHAPTER V. (p. 172), 



THE SEWERS OF PARIS AND THE PLAIN OF GENNEVILLIERS. 



The water issuing from the main sewer of the city is 

 partly turned into the Seine, partly into the plain of 

 Gennevilliers, and used, by a system of irrigation, for fer- 

 tilizing the soil. There was some fear lest the vegetable 

 mould might be saturated with fertilizing matter, but the 

 presence of a special microbe was ascertained, which re- 

 duces organic matter to its inorganic constituents, and 

 thus adapts them to be absorbed by plants. Schlcesing 

 and Muntz, who have studied this microbe, term it the 

 nitrifying microbe. The same system of sewer-irriga- 

 tion will shortly be applied to another place in the neigh- 

 bourhood of Paris, Acheres, near the forest of Saint- 

 Germain. 



