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 larvae in horse manure — Results with ineffective 

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



No. 



Series A : 

 1.... 



6.... 



Series B : 

 1.... 



Treatment of 8 bushels 

 of manure; 10 gallons 

 used whenever solu- 

 tion was applied. 



Canal larvicide, 1-75 (74 



gallons) 



Canal larvicide, 1-75 (10 



gallons) 



Canal larvicide, 1-75 (12J 



gallons) 



Iron sulphate, 14 pounds 



per gallon 



Iron sulphate, 1 pound 



per gallon 



Iron sulphate, 4 pound 



per gallon 



Control (water onlv) 



do ". 



do 



Sodium c h 1 o r i d , 24 



pounds per ga lion 



Sodium c h 1 o r i d , 1 



pound per gallon 



Copper sulphate, 1 pound 



per gallon 



Copper sulphate, i pound 



per gallon 



Control (water only) 



do 



Larval mor- 

 tality, 1 

 quart sam- 

 ple of ma- 

 nure 2 days 

 after treat- 

 ment. 



Alive. Dead 



28 



110 



5 



4 

 48 

 12 



Num- 

 ber. 

 113 



110 



179 



73 



171 



81 

 146 

 102 



76 



141 



217 



101 



132 

 322 



298 



Per 



cent. 















32.4 







25.0 

 6 

 

 



55.5 



30.0 



67.4 



57.4 

 

 



Num- 

 ber. 

 6 



1 



















15 



127 



221 







100 







Few. 

 100 

 30 



ss 



o3 - 



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 



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 



O *n 



CM - — 



£6 a 



<« 



a 



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 



10.62 



11.25 



10.50 

 6.5n 

 5.00 



4.40 



7.50 



2.75 



7.75 

 7. 75 

 7.50 



1 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 



