THE FIRST GERMAN MUNICIPAL EXPOSITION 819
grease contained in it may be extracted and refined, according to the process exhibited by Cassel.
Street-cleaning and garbage removal. For promoting cleanli- ness and healthfulness in the city the cleaning of streets and removal and disposal of sweepings and garbage occupy a posi- tion second in importance to drainage and sewerage only. Street-paving should also be mentioned just here, not only because thorough cleansing is possible only where there is good pavement ; but also because a properly constructed pavement is an integral part of the drainage system, leading away the rain- water, etc., and preventing the contamination of the ground with disease germs. Street-cleaning aids the work thus begun by street-paving and, further, prevents the contamination of the air by the dissemination of the disease-breeding foulness of the streets. Recognizing the importance of this branch of municipal activity, the Germans have given careful study to the problems presented and have developed a science of street-cleaning. The cleaning of the streets formerly was and in some cities still is, more or less in private hands; but this does not mean that the cleaning was left to private initiative, for regular times for clean- ing and regular rules to be followed were enforced. Disadvan- tages recognized in this system, however, have led to a gradual municipalization of the work. Street-cleaning as undertaken by the German municipalities is a business, not a charity, be it understood.
Promptness and thoroughness in doing the work, and relative saving of time and money, are some of the advantages of cen- tralized municipal street-cleaning. A central bureau does the office work and has general direction of the whole department. For the practical execution of the work the city is divided into districts. In charge of each district is a superintendent with a force of workmen organized into "gangs" and "flying columns." Each district has a central depot in which are the office of the district superintendent, and housing for the various implements, tools, sprinklers, sweepers, collecting wagons, carts, etc. Uni- forms or, at least, uniform caps are provided for all connected with the work. In Dresden the general director of the depart-
