DESTRUCTION OF FLY LARVAE IN HORSE MANURE. 



11 



manure. The number of bacteria was noticeably reduced, varying 

 inversely with the strength of the solution used. The amounts of 

 water-soluble nitrogen were materially lowered in the iron-sulphate- 

 treated manure, depending on the amount of iron sulphate employed. 

 The iron sulphate evidently acts as a precipitant for some of the 

 water-soluble nitrogen compounds. The ammonia was fully doubled, 

 due possibly to the reduction of alkaline reaction, two of these three 

 samples showing *a faint acidity. Iron sulphate blackened the 

 manure and deodorized it, as noted by Forbes. On the whole, we 

 find iron sulphate less effective as a larvicide than Forbes's experi- 

 ments seem to indicate. It is important, however, to note that the 

 amount of iron sulphate used by Forbes was much greater than that 

 used in these tests. 



Table I. — Destruction of fly larvw in horse manure — Results toith ineffective 

 larvicides — Gage experiments at Arlington, Va., summer of 1913. 



No. 



Series A : 

 1.... 



Series B : 

 1.... 



Treatment of 8 bushels 

 of manure; 10 gallons 

 used whenever solu- 

 tion was applied. 



Canal larvicide, 1-75 (7§ 



gallons) 



Canal larvicide, 1-75 (10 



gallons) 



Canal larvicide, 1-75 (12£ 



gallons) 



Iron sulphate, 1 J pounds 



per gallon 



Iron sulphate, 1 pound 



per gallon 



Iron sulphate, 4 pound 



per gallon 



Control (water only) 



do 



do 



Sodium c h 1 o r i d , 2\ 



pounds per gallon 



Sodium c h 1 o r i d , 1 



pound per gallon 



Copper sulphate, 1 pound 



per gallon 



Copper sulphate, \ pound 



per gallon 



Control (water onlv) 



do. 



Larval mor- 

 tality, 1 

 quart sam- 

 ple of ma- 

 nure 2 days 

 after treat- 

 ment. 



Alive. Dead 



Num 

 her. 

 113 



110 



179 



73 

 171 



81 

 146 

 102 



76 



141 



217 



101 



132 

 322 



298 



Per 



cent. 

 











32.4 







25.0 

 

 

 



55.5 



30.0 



67.4 



57.4 

 

 



Num 



ber. 



6 



1 



















15 



127 



221 







100 







Few. 

 100 

 30 



ss 



Mil- 

 lions. 

 3,700 



2,600 



1,600 



700 



970 



2,890 

 5,200 

 6,000 

 5,100 



648 



4,070 

 3,060 

 4,800 



Per 



cent. 

 0.73 



.61 



,53 



1.05 



.67 



.76 

 .84 

 .68 

 .65 



.51 



Water extract. 



In per cent 



of total 



nitrogen. 



Per 



cent. 

 35.62 



34.43 



32.08 



10.48 



16.42 



22.37 

 26.19 

 25.00 

 18.46 



32.94 



28.67 



9.71 



14.93 

 23.45 

 21.11 



2 fco 



° a 



Per 



cent. 

 6.58 



3.93 



3.96 



5.05 



6.72 



6.84 

 2.62 

 3.09 

 2.46 



7.65 



3.78 



3.78 



2.40 

 2.55 

 2.08 



C.c. 

 12.00 



5.50 



5.75 



1.50 



J 0.62 



U.25 



10.50 

 6.5Q 

 5.00 



4.40 

 7.50 

 2.75 



7.75 



7.75 

 7.50 



Acidity. 



SODIUM CHLORID (TABLE SALT) 



The results of two cage experiments with manure treated with 

 sodium chlorid are given in Table I, Series B, Nos. 1 and 2. The 

 corresponding control cages are numbered 5 and 6. The average 



