INSECT POWDER. 



43 



resemble that of chamomilo. This method is somewhat different 

 from that given by them in 1S98 (42), a slight modification of Dur- 

 rant's test in which the extraction of the sample with ether was 

 continued as long as the solvent took up anything, instead of ex- 

 hausting with a specified quantity of ether. This method differs 

 from that published b}^ Fromme in 1 900 only in the time of macera- 

 tion, being two hours instead of one. 



Caesar and Loretz (42) found that insect powder made from closed 

 flowers yielded from 8 to 9.5 per cent of extract, while open or partly 

 open flowers gave 6.5 to 7.5 per cent. They state that the color of 

 the extractions varies from pure yellow, dark yellow, and brownish 

 yellow to gi^eenish yellow, while that prepared from stems is of a 

 dirty-green color, and the residue amounts to only 5.5 per cent. 

 They state furthermore that the insecticidal properties of insect 

 powder are fully represented in the ether extract, and are not due 

 to any alkaloidal bodies that the powder may contain. 



Linke (173) obtained the values shown in Table 20 on six authentic 

 powders. 



Table 20. — Chemical analysis of authentic insect powders and whole flowers (Linke). 





Determination. 



Sample No. 



Moisture 



(loss at 



100-105°). 



Ether 



extract 



(Durrant's 



method). 



Ash. 



Powder: 



1 



Per cent. 

 9.08 

 9.64 

 7.20 

 6.66 

 6.22 

 5.24 



10.72 

 10.36 

 10.76 



Per cent. 

 4.28 

 6.48 

 16.56 

 6.22 

 6.26 

 5.56 



Per cent. 

 7.04 



2 



7.52 



3 



7 64 



4 





5 





6 



6.56 



Whole flowers: 



1 



5.88 



2 . 





6.44 



3 





6.44 









1 6. 80 per cent when shaken continuously for 2 hours. 



In the ash, the presence of iron, manganese, aluminum, calcium, 

 magnesium, sodium, and potassium was shown, but in no instance 

 was chromium found. After evaporating the ethereal solution the 

 residue was dried at 100° C. for one hour before weighing. 



Sattler (238) reports finding lead clu-omate in an insect powder, 

 the ash of which was 6.105 per cent. Wiebelitz (293), 1912, found 

 a lower ash content in two samples of insect powder than that usually 

 reported, namely, 4.7 per cent and 5.1 per cent. Siedler (150), in 

 1912, obtained the results given in Table 21 on pure insect powder 

 and on stem powder. 



