INSECT POWDER. 
Table 2. — Physiological examination of insect powder. 1 
23 
Product. 
Commercial powder ground from wild flowers 
Commercial powder ground from Montenegrin closed flowers. . . 
Commercial powder ground from Dalmatian half-closed flowers . 
Commercial powder ground from Dalmatian open flowers 
Commercial powder 
Commercial powder ground from open Dalmatian flowers 
Commercial powder ground from closed Dalmatian flowers 
Commercial powder ground from closed Montenegrin flowers. . . 
Commercial powder 
Powdered closed flowers grown at Korneuburg, 1913 
Powdered half-open flowers grown at Korneuburg, 1913 
Powdered closed flowers grown at Korneuburg, 1914 
Powdered half-open flowers grown at Korneuburg, 1914 
Powdered open flowers grown at Korneuburg, 1914 
Powdered stems grown at Korneuburg, 1914 
Time required. 
Mini- 
mum. 
Min. 

1 
2 
5 
2 


3 
1 




3 
Sec. 
40 
04 
00 
03 
50 
20 
45 
40 
52 
20 
54 
45 
40 
40 
05 
Maxi- 
mum. 
Min. Sec. 
Average. 
Min. Sec. 
1 09 
i 50 tests were made on each sample. 
In testing the action of insect powder against various insects Smith 
(263) and many other entomologists used different brands of com- 
mercial insect powders. Their results were comparative, as they 
were without samples of known purity, and their experiments are 
without value in showing the presence of adulterants. 
MICROSCOPICAL METHODS. 
There has been much divergence of opinion as to the value of a 
microscopical examination of an insect powder in determining its 
genuineness. For instance, Jelliffe (148) concludes that "the 
microscope is the only possible means for detecting the presence of 
powdered stems in insect powder." On the other hand, Beringer 
(29), after examining genuine insect powder and the powder made 
from the flowers of the Hungarian daisy, says, " Microscopically no 
difference could be detected between the two powders." Howie 
(139) states that he finds chemical methods more exact and trust- 
worthy than microscopical ones for detecting added fustic, chrome, 
and turmeric. Again, in discussing Kirkby's (156) paper, he says 
that he has little faith in microscopical observation for ascertaining 
the value of an insect powder, the physiological test with the black 
beetle being the best. 
For recognizing the presence of certain adulterants, as for instance 
starch or starch-bearing materials, the microscopical examination 
is of great value, but in the powdered state flowers oi certain of the 
Composite closely allied to Pyrethrum are so similar to insect flowers 
as to render their detection difficult. Again, although an adulterant 
can usually be detected qualitatively by the microscope, no exact 
quantitative method has as yet been devised for its determination. 
