THE HOUSE-FLY 21 



that this material is also impracticable. It does not 

 penetrate a large pile of manure with sufficient ease to 

 reach all of the maggots unless so large quantities are 

 used that the cost becomes prohibitive. Ordinary slaked 

 lime has not proved an efficient destroyer of the maggots. 



J. J. Davis of the University of Illinois, under the direc- 

 tion of S. A. Forbes, carried out some interesting experi- 

 ments in the treatment of manure piles with iron sulphate. 

 This treatment proved so successful in killing the maggots 

 that it seemed possible to make certain recommendations, 

 namely, that a solution of iron sulfate, two pounds in 

 a gallon of water, or two and one-half pounds of dry 

 sulfate would be sufficient for one horse each day. 

 Iron sulfate is so cheap that it would not cost over two 

 cents a horse a day and, in addition, it completely 

 deodorizes the manure. As a basis for this recommenda- 

 tion, it was estimated that the average driving horse 

 produces about fifteen pounds of manure a day, while 

 a working horse might produce twice that amount. But 

 a large part of the manure of the working horse is dropped 

 out-of-doors, so that, perhaps, no more would accumulate 

 for treatment than for a driving horse. 



The storage and removal of manure. It has been 

 shown that flies prefer light, open places in which to breed 

 and that they rarely enter dark rooms to deposit their 

 eggs. It therefore becomes an inexpensive and simple 

 matter to build a dark, well screened room or a tight 

 cement pit in which the manure can be stored for a long 

 time or, if preferred, can be removed once or twice a week. 



Herms describes and illustrates several forms of re- 

 ceptacles for the storage of manure in use in Berkeley, 

 California. He says, "Where only one horse is stabled 



