oo BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE 
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 
On water-free basis 
Soluble in— 
Sample No. 
; Moisture eee eb eee Se ey 8 ol seen erro 
oss at Ash | 
ce Ether Equal 
Ordinary} Purest mixture | 
| petro- petro- Chloro- | of chloro- 
Specific | Specific leum leum form |formand 
gravity, | gravity, ether ether ether 
0.735 0.720 (0.720) 
a 
Powders prepared 
from closed flowers: | Per cent.| Per cent | Per cent | Per cent | Per cent | Per cent | Per cent | Per cent 
1 eee a ee es eu 7. 43 7. 68 9. 38 7 (ACB pares pated) Sis paw en.) 7. 02 6. 81. 
ds at See cape ie Ne WY 3. 42 8. 26 8.59 ML Ere Te ee) ea ete Pee re eee Se eee 
OSE age Non Mee ere eo 8. 28 Te2l pec eA OE ee ce ee ee ir | iret An re 
Eco o105 Oe ae i. 8. 10 Toei! 8. 14 [otis be DE SEG Sa RSF ek See 
CFS ea ae UT Se 6. 16 8. 34 8. 23 yess s Sle ees 35686). 2. tlle ae 
GSa ene os ae Ore Se 7. 41 6. 70 6. 44 4.35 2. 50 2. GL ee ee 
eer ha es tee 6. 95 7.70 6. 46 5. 24 3205 3. 120 TS ee Ce ee 
ee ei et 4. 55 7.77 6. 7 5. 01 2. $3 2. 69sec: 5 2c Pa 
UES ae, 8 Peale SE te 8. 90 6. 65 6. 7. Oe 787 [Eis oF ee 3235) 22 ea ee 
ee ee ie 6. 75 6. 71 Sales renee 2. 83 5. 26 5. Fa 
sh sieaen= ip neare ahd ma 9.85 7.08 7.41 4. 88 PETG: 202-6 oes 2 eee 
2 iss eed SERIES 8. 48 7. 67 6. 59 4. 49 2. 60 22463 5: Se eee 
SB aes eee ee 8. 06 7. 49 6. 12 5. 92 3. 03 2597. Wont ol ese ee 
Minimum_._____ 3. 42 6. 65 6. 12 4,35 2.5 2. 02 * 5.26 5: 14 
Maximum.--__-_ 9. 85 8. 34 9. 38 7. 74 Salo 3. 68 7. 02 6. 81 
Averages. S20 7. 08 Waa2, 7. 30 5. 58 2. 83 2. 86 6. 14 5. 99) 
Commercial powders: : 
Hee SIS ed AGS 8. 33 6. 85 4. 34 DAQR aR aY Soa 1253) SS ee 
De redo de wena fe 7. 76 6. 58 4. 66 3215 le D2) epee baer eee ee 
ee eee re Meurer 9.15 9. 08 UGS: Bilbo 4 |eeeeee 22 oe 2: 647 a ee 
i, US rare baer or mnES 7. 03 8. 37 5. 19 4. 97 2. 48 2 29s ee 2. 834 
| eee ay 5 See 7. 63 8. 14 6. 09 Ay 5DN 2 so eee 5 264 b= eS eee 
(57 ee ee Se 7. 88 6. 83 6. 87 4. 04 3. 03 2. 91 4. 87 5.19 
ete erecen eter pees 11. 79 6. 63 6. 03 4, 29 2. 48 238° Et eee i 
SS ERs Se eet ae 8. 68 7. 36 8. 68 Sala 3. 47 3. 29 6. 03 5. 86 
Oe ee bases 9. 20 6. 94 8. 51 6. 17 3. 09 287 Ss ee eee 3 
LOL LAS eS oe es 6. 70 8. 10 6. 18 3. 52 2.,07,\. S458 ee ee 
TT) ead aie a 8. 62 7.45 4.41 2.41 60. i 2S eS eee 
5 ce IMS TERE Tae 4, 55 10. 89 34 7/ 3. 43 2.79: |b 2 ee ee eee 
Minimum______ 4. 55 6. 63 She 2. 41 1. 60 1. 53 4. 87 2. 83 
Maximum__-_-_-__ 11. 79 10. 89 8. 68 6. 17 3. 47 3. 29 6. 03 5. 86 
Average________ 8.11 7.77 5. 99 4,15 2. 63 2. 56 5.45 4. 63 
