maggots of the house fly. It is safe to say that on an average many 

 ilionsands of perfect flies issued from it every day, and that at least 

 a hirge share of the flies which constantly bothered the employees in 

 the two buildings mentioned came from this source. 



On the basis of tlie ex})eriments of 18i)7. an attempt was made 

 beginning early in April, 181)8, to prevent the breeding of house flies 

 about the Department by the treatment of this manure pile with 

 kerosene. The attempt was begun early in April and was carried on 

 for some weeks. While undoubtedlv hundreds of thousands of flies 

 were destroyed in the course of this work, it was found by the end of 

 May that it was far from perfect, since used at an economical rate the 

 kerosene could not be made to penetrate throughout the whole pile of 

 manure, even when copiously washed down with water. A consider- 

 able proportion of house fly larva? escaped injury from this treatment^ 

 which at the same time was found, even at an economical cost, to be 

 laborious, and such a measure in fact as almost no one could be 

 induced to practically adopt. 



There remained, however, another measure which nad been sug- 

 gested by the writer in an article on the house fly published in 1895, 

 namely, the preparation of an especial receptacle for the manure, and 

 this was very readily done. A closet G by 8 feet had been built in the 

 corner of the stable nearest the manure joile. It had a door opening 

 into the stable proper, and also a window. A door was built in the 

 outside wall of this closet, and the stablemen were directed to place 

 no more manure outside the building; in other words, to abolish the 

 outside manure pile, and in the future to throw all of the manure 

 collected each morning into this closet, the window of which in the 

 meantime had been furnished with a wire screen. The preparations 

 were completed by the middle of June, and a barrel of chlorid of lime 

 was put in the corner of the closet. Since that time every morning 

 the manure of the stable is thrown into the closet and a small shovel 

 full of chlorid of lime is scattered over it. At the expiration of ten 

 davs or two weeks the gardeners open the outside door, shovel the 

 mauure into a cart, and carry it off to be thrown upon the grounds. 



Judging from actual examination of the manure pile, the measure 

 is eminently successful. Very few flies are breeding in the jn'oduct of 

 the stable Avhich formerly gave birth to many thousands daily. After 

 this measure had been carried on for two weeks, employees of the 

 Department who had no knowledge of the work that was going on 

 were asked whether they had noticed any diminution in tlie number 

 of flies in their offices. Persons in all of the offices on the first floor of 

 the two buildings were asked this question. In every office except 

 one the answer was that a uinrked decrease had been noticed, so that 

 the work must be considered to have hemi successful. 



The account of this remedial work has been given with souie detail 



[Cir. .^5] 



