Oct. 15,1917 
Manganese in Insect Flowers 
81 
Table II .—Analyses of Chrysanthemum cinerariaefolium. Average of all determina¬ 
tions, including many not reported in Table I a 
Description. 
Manganese. 
Nitrogen. 
Phosphoric acid 
Japanese stems. 
Per cent. 
0.0123 
. 0077 (n) 
• 015s (9) 
. 0096 (13) 
Per cent. 
0.928 (12) 
* 733 (61) 
1.813 (48) 
i- 759 ( 55 ) 
Per cent . 
0. 326 (12) 
. 192 126) 
. 680 (15) 
. 700 (19) 
Dalmatian stems. 
Japanese closed flowers. 
Dalmatian closed Flowers. 
Japanese open flowers. 
Dalmatian open flowers. 
. 0076 (13) 
1. 267 (104) 
• 532 (94) 
a The numbers in parentheses indicate the number of samples on which the determination in question 
was made. 
It is seen that a high manganese content is accompanied by an in¬ 
creased amount of nitrogen and phosphoric acid rather than the reverse. 
From the above results we may conclude that the determination of 
manganese in an insect powder is worthless for ascertaining whether it 
has been adulterated with pyrethrum stems. In a rough way a large 
amount of manganese indicates a product of Japanese origin, but the 
variation in the content of manganese is so great in pyrethrums from the 
same country that this test can not be applied with certainty to deter¬ 
mine the geographic origin of an insect powder. In other words, the 
determination of manganese in a sample of insect powder supplies little 
or no useful information with respect to its purity, and Unger's method 
is shown to be valueless. Furthermore, the amount of manganese ab¬ 
sorbed by plants of C. cinerariaefolium is so small as not to affect ap¬ 
preciably the ratio between the nitrogen and phosphoric acid of the stem 
and of the flowers. 
SUMMARY 
(1) Quantitative data are presented on the manganese content of 
stems, "open” flowers, and "closed” flowers of Chrysanthemum cinerari¬ 
aefolium of both Dalmatian and Japanese origin. 
(2) It is shown that the manganese content of both stems and flowers 
varies so much and is so little different in these two parts of the plant 
as to render valueless any method for estimating the amount of powdered 
stems in an insect powder from a determination of its manganese content. 
(3) Pyrethrum of Japanese origin contains more manganese than that 
from other countries, owing presumably to the high manganese content 
of the volcanic soils of Japan. 
(4) An increase in the manganese content of pyrethrum is accompanied 
by a slightly higher nitrogen and phosphoric-acid content. 
