INSECT POWDER. 



39 



results with the physiological test because of the difference in size, 

 health, etc., of the insects. In good samples of insect powder the 

 ether extract varies between 5 and 9 per cent." 



Dietze (70), of the firm of J. D. Riedel, Berlin, records numerous 

 tests on insect powders (Table 15). He used powder ground by 

 himself from closed flowers, and also commercial powders. Dietze 

 prefers petroleum ether to ordinary ether as a solvent, as the former 

 takes out the " active principle only," whereas ordinary ether extracts 

 a number of other substances at the same time. In most cases the 

 ether extract is more or less green, and has a less powerful odor than 

 the petroleum-ether extract. Table 16 shows the results obtained 

 upon various adulterants of insect powder. 



Table 15. — Chemical analysis of insect -powder {Dietze). 





Determination. 





Moisture 



(loss at 



100°). 



Ash. 



On water-free basis. 



Sample No. 



Soluble in— 





Ether. 



Ordinary 

 petro- 

 leum 

 ether. 



Purest 

 petro- 

 leum 

 ether. 



Chloro- 

 form. 



Equal 

 mixture 





Specific 



gravity, 



0.735. 



Specific 

 gravity, 

 0.720. 



of chloro- 

 form and 

 ether 

 (0.720). 



rowders prepared 

 from closed flowers: 

 1 



Per cent. 

 7.43 

 3.42 

 5.51 

 8.10 

 6.16 

 7.41 

 6.95 

 4.55 

 8.90 

 7,23 

 9.85 

 8.48 

 8.06 



Per cent. 

 7.68 

 8.26 

 8.28 

 7.37 

 8.34 

 6.70 

 7.70 

 7.77 

 6.65 

 6.75 

 7.08 

 7.67 

 7.49 



Per cent. 

 9.38 

 8.59 

 7.27 

 8.14 

 8.23 

 6.44 

 6.46 

 6.78 

 6.78 

 6.71 

 7.41 

 6.59 

 6.12 



Percent. 

 7.41 



Per cent. 



Per cent. 



Per cent. 

 7.02 



Per cent. 

 6.81 



2 









3 













4 













5 



7.74 

 4.35 

 5.24 

 5.01 

 5.78 

 5.01 

 4.88 

 4.49 

 5.92 





3.68 

 2.61 

 3.12 

 2.69 

 3.35 

 2.83 

 2.02 

 2.46 

 2.97 







6 



2.50 

 3.15 

 2.93 







7 







8 







9 







10 





5.26 



5.17 



11 



2.76 

 2.60 

 3.03 





12 







13 













Minimum 



Maximum 



Average 



Commercial powders: 

 1 



3.42 

 9.85 

 7.08 



8.33 

 7.76 

 9.15 

 7.03 

 7.63 

 7.88 

 11.79 

 8.68 

 9.20 

 6.70 

 8.62 

 4.55 



6.65 

 8.34 

 7.52 



6.85 

 6.58 

 9.08 

 8.37 

 8.14 

 6.83 

 6.63 

 7.36 

 6.94 

 8.10 

 7.45 

 10.89 



6.12 

 9.38 

 7.30 



4.34 

 4.66 

 7.28 

 5.19 

 6.09 

 6.87 

 6.03 

 8.68 

 8.51 

 6.18 

 4.41 

 3.72 



4.35 

 7.74 

 5.61 



2.98 

 3.15 

 5.12 

 4.97 

 4.52 

 4.04 

 4.29 

 5.17 

 6.17 

 3.52 

 2.41 

 3.43 



2.50 

 3.15 

 2.99 



2.52 

 3.68 

 2.86 



1.53 



5.26 

 7.02 

 6.14 



5.17 

 6.81 

 5.99 



2 









3 





2.64 

 2.29 

 2.64 

 2.91 

 2.38 

 3.29 

 2.81 







4 



2.48 





2.83 



5 







6 



3.03 

 2.48 

 3.47 

 3.09 

 2.07 

 1.60 

 2.79 



4.87 



5.19 







8 



6.03 



5.86 



9 





10 







11 









12 

















Minimum 



Maximum 



Average 



4.55 

 11.79 

 8.11 



6.63 

 10.89 



7.77 



3.72 



8. 68 

 5.99 



2.41 

 6.17 

 4.15 



1.60 

 3.47 

 2.63 



1.53 

 3.29 

 2.56 



4.87 

 6.03 

 5.43 



2.83 



5.86 

 4.63 



