INSECT POWDER. 



57 



amount of certain ingredients present in Pyrethrum flowers and stems 

 aids the analyst to determine from the analysis of an unknown com- 

 mercial insect powder whether or not it is adulterated with powdered 

 Pyrethrum stems. 



By the color of the ether extract and by a determination of the 

 nitrogen, phosphoric acid, and crude fiber, together with a micro- 

 scopical examination, the presence of powdered stems in insect pow- 

 der can be shown qualitatively and an approximate determination 

 of the amount of stems can be made. 



Table 36 summarizes all the results for nitrogen, phosphorus pen- 

 toxid, crude fiber, ash, ash insoluble in hydrochloric acid, pentosans, 

 ether extract, moisture, and extraneous material, for stems and the 

 three commercial grades of flowers, of both Dalmatian and Japanese 

 origin. 



Table 36. — Summary of examination of insect flowers and stems. 



Product. 



a 



1 

 2 



O 



1 



O 





<l3 



s 



s 

 ^1 



ll 



a 



1 

 o 



1 

 m 





T ,, , J,) (Min.. 



Per 

 cent. 

 1.61 

 2.01 

 1.813 

 48 



1.53 

 2.09 

 1.759 

 55 



1.53 

 2.09 

 1.784 

 103 



1,40 

 1.75 



1.566 

 18 



1.17 

 1.40 

 1.267 

 104 



0.610 

 1.12 

 .928 

 12 



0.547 

 .960 

 .733 



6 



0.547 

 1.12 



.765 

 18 



Per 



cent. 

 0.620 



.758 

 .680 

 15 



0.591 

 .815 

 .700 

 19 



0.591 

 .815 

 .691 

 34 



0.528 

 .599 



.562 

 4 



0.451 

 .667 

 .532 

 94 



0. 125 

 .411 

 .326 

 12 



0.117 

 .345 

 .192 

 26 



0.117 

 .411 

 .234 

 38 



Per 

 cent. 

 21.46 

 24.70 

 23.11 

 15 



18.65 

 22.89 

 20.81 

 12 



18.65 

 24.70 

 22.09 

 27 



27.20 

 35.85 

 31.02 

 28 



32.39 

 48.79 

 44.38 

 12 



33.54 

 42.98 

 37.69 

 15 



32.39 



48.79 

 40.66 

 27 



Per 



cent. 

 6.03 

 8.58 

 7.18 

 48 



6.12 



8.28 

 7.22 

 55 



6.03 

 8.58 

 7.20 

 103 



6.14 

 7.95 



7.07 

 17 



4.88 

 7.87 

 6.09 

 104 



3.40 

 6.24 

 5.38 

 12 



3.60 

 6.70 

 4.68 

 26 



3.40 

 6.70 

 4.90 

 38 



Per 

 cent. 

 0.19 

 2.03 

 .79 

 48 



0.05 

 .91 

 .23 



55 



0.05 

 2.03 

 .49 

 103 



0.12 

 .74 

 .31 

 17 



0.06 

 1.38 

 .26 

 104 



0.06 

 1.69 

 .95 

 12 



0.09 

 .59 

 .29 

 26 



0.06 

 1.09 

 .50 

 38 



Per 



cent. 



Per 

 cent. 



Per 

 cent. 



Per 



cent. 



Per 

 cent. 



Per 



cent 



Japanese "cl osed" J^i"'-- 

 ^o^ers \f^l- 



























No. samples examined. . 















Dalmatian "closed" J JJ'^L- ■ 



fl^^e-^s lAvf:: 



No. samples examined. . 

 All "closed" flowers (Min 



16.06 



17.75 



16.66 



5 



5.99 

 7.45 

 6.87 

 6 



3.05 

 5.03 

 4.11 

 5 



4.40 

 7.55 

 5.37 

 13 



0.57 

 6.44 

 2.72 

 19 



0.11 

 .75 

 .30 



7 



(Japanese and Dal- -(Max.. 

 matian). .[Ave.. 



























No. samples examined. . 

 (Min 





















4.90 

 6.44 

 5.68 

 4 



4.81 

 9.21 

 6.69 



17 



0.62 

 5.05 

 2.51 

 8 



0.88 

 4.99 

 2.33 

 45 



14 











.39 











81 



No. samples examined . . 



(Min.. 

 "Open" flowers •JMax.. 



No. samples examined . . 



Min.. 



19.98 

 21.72 

 21.11 

 5 



5.09 

 6.60 

 5.81 

 8 



3.50 

 4.70 

 4.06 



8 



4 



0.10 

 .90 

 .47 



9 



Japanese stems < Max. . 



Ave.. 



























No. samples examined. . 



Min.. 



Dalmatian stems <Max.. 



(Ave.. 

 No. samples examined. . 



Allstems(JapaneseandJ?iJ°- ■ 

 Dalmatian) |^^^^;; 



No. samples examined . . 



17.54 

 18.78 

 18.21 

 5 



2.34 

 3.98 

 3.22 



7 



1.53 



2.78 

 1.97 



7 



4.51 

 7.20 

 5.40 

 14 





0.38 

 8.89 

 3.93 



9 



In estimating the amount of stems in an unknown sample, its 

 nitrogen and phosphorus pentoxid contents are compared with the 



