-19- 
Extract 
Process of 
Dilution in 
Apprpxima te 
Total 
Kill after 
No. 
extraction 
gin. of root 
dilutions in 
larvae 
24 hours 
gm. of rotenone 
Number 
Percent 
1 
Soxhlet 
1:10,000 
1: 250,000 
268 
100 
acetone 
20,000 
500,000 
290 
95 
40,000 
1,000,000 
386 
92 
80,000 
2,000,000 
205 
80 
2 
Soaked iri 
1:10,000 
1: 250,000 

— 
acetone 
: 20,000 
500 , 000 
271 
98 
40,000 
1,000,000 
286 
85 
80,000 . 
2,000,000 
211 
76 
4 
Soaked in 
1:20,000 
280 
95 
alcohol 
40,000 
286 
90 
80,000 
329 
73 
5& 
Cold water 
1:10,000 
208 
99 
20,000 
216 
100 
40,000 
'"b 
433 
94 
80,000 
290 
51 
6 
Hot water 
1:10,000 
226 • 
100 
20,000 
, 284 
99 
40,000 
, 
346 
86 
80 , 000 
281 
51 
7 
Mixture of 
1:10,000 
208 
93 
acetone and 
20 , 000 
284 
90 
veter 
40,000 
368 
74 
80\000 
228 
46 
15 
F-ure rotenone 
1: 250,000 
292 
92 
dissolved 'i 
.n 
500 , 000 
297 
79 
acetone 
800,000 
213 
70 
. 
1,000,000 
321 
50 
2,000,000 
265 
10 
Check (average from several series of tests) 
880 
The secondary extracts from the alcohol end acetone residues 
ranked ve*v low in toxicity, ^n the other hand, the. -toxicity of 
the secondary extract from the water residue "as practically as 
high at dilutions of 20,000 and 10,000 as were the primary extracts. 
The results of toxicity tests of secondary extracts of derris-root 
residue to mosnuito larvae '"pre as follows: 
