The House-fly as a Carrier of Disease 159 



"The reason for applying the borax to the fresh manure immedi- 

 ately after its removal from the stable is that the flies lay their eggs 

 on the fresh manure, and borax, when it comes in contact with the 

 eggs, prevents their hatching. As the maggots congregate at the 

 outer edge of the pile, most of the borax should be applied there. 

 The treatment should be repeated with each addition of fresh manure, 

 but when the manure is kept in closed boxes, less frequent applica- 

 tions will be sufficient. When the calcined colemanite is available, 

 it may be used at the rate of 0.75 pound per 10 cubic feet of manure, 

 and is a cheaper means of killing the maggots. In addition to the 

 application of borax to horse manure to kill fly larvas, it may be 

 applied in the same proportion to other manures, as well as to refuse 

 and garbage. Borax may also be applied to the floors and crevices in 

 barns, stables, markets, etc., as well as to street sweepings, and water 

 should be added as in the treatment of horse manure. After estimat- 

 ing the amount of material to be treated and weighing the necessary 

 amount of borax, a measure may be used which will hold the proper 

 arrount, thus avoiding the subsequent weighings. 



" While it can be safely stated that no injurious action will follow 

 the application of manure treated with borax at the rate of 0.62 

 pound for eight bushels, or even larger amounts in the case of some 

 plants, nevertheless the borax-treated manure has not been studied 

 in connection with the growth of all crops, nor has its ' cumulative 

 effect been determined. It is therefore recommended that not more 

 than 1 5 tons per acre of the borax-treated manure should be applied 

 to the field. As truckmen use considerably more than this amount, 

 it is suggested that all cars containing borax-treated manure be so 

 marked, and that public-health officials stipulate in their directions 

 for this treatment that not over 0.62 pound for eight bushels of manure 

 be used, as it has been shown that larger amounts of borax will 

 injure most plants. It is also recommended that all public-health 

 officials and others, in recommending the borax treatment for kill- 

 ing fly eggs and maggots in manure, warn the public against the 

 injurious effects of large amounts of borax on the growth of plants." 



"The amount of manure from a horse varies with the straw or 

 other bedding used, but 12 or 15 bushels per week represent the 

 approximate amount obtained. As borax costs from five to six 

 cents per pound in loo-pound lots in Washington, it will make the 

 cost of the borax practically one cent per horse, per day. And if 

 calcined colemanite is purchased in large shipments the cost should 

 be considerably less." 



