122 AGRICULTURAL BACTERIOLOGY. 



there has been an attempt made in recent years to utilize the 

 material in sewage for fertilizing the soil. Sewage farms have 

 been established in large numbers in the last twenty -five years, 

 the design of which is to make use of this waste product. On 

 these farms the sewage is distributed over the fields by proper 

 conduits and the contents of the sewage thus restored to the 

 soil for the use of crops. Upon the fields thus irrigated vari- 

 ous garden crops are raised. For a time great claims were 

 made for these sewage farms. The returns seemed to indicate 

 an increased yield and an actual utilization of this waste prod- 

 uct. Large numbers of such sewage farms were organized in 

 England and in continental Europe. The great cities of Paris 

 and Berlin have established enormous sewage farms in their 

 neighborhood to use their sewage. Berlin in particular has 

 many thousands of acres under such cultivation. These great 

 sewage farms near Paris and Berlin have undoubtedly been 

 very successful. 



But at the present time one hears little in regard to this 

 method of utilizing sewage, and sewage farms are not increas- 

 ing. Theoretically the plan is ideal since it puts back into the 

 soil a waste product. But practically it is only under special 

 conditions that it is successful and many of the sewage farms 

 are run at a loss. The reasons for this are chiefly the follow- 

 ing : The organic matter in the sewage is not in condition to 

 be utilized by plants. It must first undergo the process of 

 decomposition and nitrification. If too much sewage is applied 

 to the soil the bacteria cannot take care of it and the soil 

 becomes clogged. Hence to procure good results a large 

 amount of land is required. It is usually stated that an acre 

 of land will take care of the sewage of only about fifty per- 

 sons. Hence it is only where there are large tracts of sandy 

 soil near a city, as is the case around Berlin, that sewage farm- 

 ing can be practical. Again, the manurial value of sewage, at 

 best, is small on account of its extreme dilution. Crops can 



